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A simple example

Imagine there's a small forest behind your house. You can take wood from the forest to build a fire, repair the roof or add extra rooms if you need more space.

If you get greedy and take wood more quickly than the trees can grow back, the forest will get smaller and eventually disappear. But if you manage the forest sustainably, only taking as much as can naturally regrow, you'll enjoy a steady supply of wood forever.

Of course, in the real world, sustainability isn't usually this simple. The most important resources are part of huge, complex systems that are linked in unexpected ways. But the basic idea of staying in balance with nature as it regenerates itself still holds true.

Sustainability as a marketing term

Most people agree that sustainability is a good idea. And because it sounds so positive, companies and governments like to describe things they do as sustainable - even when they're not. It's true that some things are more sustainable than others, but even the most efficient oil-fueled car will eventually run out of atmosphere to pollute.

When you see a product or policy being described as sustainable, ask yourself: could they keep doing this forever without causing any harm? If the answer is no, it's probably not sustainable.

A sustainable system

The truth is, it's actually quite difficult for something to be truly sustainable, especially if it's happening on a large scale. For a long time, societies like ours in the UK have been built around unsustainable ways of doing things. It's not just that everyone's allowed to take more than their fair share - things are often set up so it's impossible not to.

Moving to a sustainable system is the greatest challenge of this century. And we'll only succeed by moving together, with the most powerful taking the lead. That's why Greenpeace mainly targets governments and big companies with its campaigns. By getting them to stop unsustainable practices and write better rules, we can build a green, peaceful world that'll last long into the future.

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What is sustainability? A simple guide to a vital idea

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Most environmental problems come from using natural resources unsustainably. But what does sustainability really mean? Let's find out.

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Sampling Methods: Types, Techniques & Best Practices

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Researchers use a variety of sampling methods and techniques. ✓ Learn how sampling works, best practices, and the best type to use for your next survey.

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The scientific method is a process of research with defined steps that include data collection and careful observation.

Observation

Scientific advances begin with observations. This involves noticing a pattern, either directly or indirectly from the literature. An example of a direct observation is noticing that there have been a lot of toads in your yard ever since you turned on the sprinklers, where as an indirect observation would be reading a scientific study reporting high densities of toads in urban areas with watered lawns.

During the Vietnam War (figure \(\PageIndex{a}\)), press reports from North Vietnam documented an increasing rate of birth defects. While this credibility of this information was initially questioned by the U.S., it evoked questions about what could be causing these birth defects. Furthermore, increased incidence of certain cancers and other diseases later emerged in Vietnam veterans who had returned to the U.S. This leads us to the next step of the scientific method, the question.

Figure \(\PageIndex{a}\): A map of Vietnam 1954-1975. Image from Bureau of Public Affairs U.S. Government Printing Office (public domain).

Question

The question step of the scientific method is simply asking, what explains the observed pattern? Multiple questions can stem from a single observation. Scientists and the public began to ask, what is causing the birth defects in Vietnam and diseases in Vietnam veterans? Could it be associated with the widespread military use of the herbicide Agent Orange to clear the forests (figure \(\PageIndex{b-c}\)), which helped identify enemies more easily?

Figure \(\PageIndex{b}\): Agent Orange drums in Vietnam. Image by U.S. Government (public domain).

Figure \(\PageIndex{c}\): A healthy mangrove forest (top), and another forest after application of Agent Orange. Image by unknown author (public domain).

Hypothesis and Prediction

The hypothesis is the expected answer to the question. The best hypotheses state the proposed direction of the effect (increases, decreases, etc.) and explain why the hypothesis could be true.

OK hypothesis: Agent Orange influences rates of birth defects and disease.

Better hypothesis: Agent Orange increases the incidence of birth defects and disease.

Best hypothesis: Agent Orange increases the incidence of birth defects and disease because these health problems have been frequently reported by individuals exposed to this herbicide.

If two or more hypotheses meet this standard, the simpler one is preferred.

Predictions stem from the hypothesis. The prediction explains what results would support hypothesis. The prediction is more specific than the hypothesis because it references the details of the experiment. For example, "If Agent Orange causes health problems, then mice experimentally exposed to TCDD, a contaminant of Agent Orange, during development will have more frequent birth defects than control mice" (figure \(\PageIndex{d}\)).

Figure \(\PageIndex{d}\): The chemical structure of TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin), which is produced when synthesizing the chemicals in Agent Orange. It contaminates Agent Orange at low but harmful concentrations. Image by Emeldir (public domain).

Hypotheses and predictions must be testable to ensure that it is valid. For example, a hypothesis that depends on what a bear thinks is not testable, because it can never be known what a bear thinks. It should also be falsifiable, meaning that they have the capacity to be tested and demonstrated to be untrue. An example of an unfalsifiable hypothesis is "Botticelli's Birth of Venus is beautiful." There is no experiment that might show this statement to be false. To test a hypothesis, a researcher will conduct one or more experiments designed to eliminate one or more of the hypotheses. This is important. A hypothesis can be disproven, or eliminated, but it can never be proven. Science does not deal in proofs like mathematics. If an experiment fails to disprove a hypothesis, then we find support for that explanation, but this is not to say that down the road a better explanation will not be found, or a more carefully designed experiment will be found to falsify the hypothesis.

Hypotheses are tentative explanations and are different from scientific theories. A scientific theory is a widely-accepted, thoroughly tested and confirmed explanation for a set of observations or phenomena. Scientific theory is the foundation of scientific knowledge. In addition, in many scientific disciplines (less so in biology) there are scientific laws, often expressed in mathematical formulas, which describe how elements of nature will behave under certain specific conditions, but they do not offer explanations for why they occur.

Design an Experiment

Next, a scientific study (experiment) is planned to test the hypothesis and determine whether the results match the predictions. Each experiment will have one or more variables. The independent variable is what scientists hypothesize might be causing something else. In a manipulative experiment (see below), the independent variable is manipulated by the scientist. The d ependent variable is the response, the variable ultimately measured in the study. Controlled variables (confounding factors) might affect the dependent variable, but they are not the focus of the study. Scientist attempt to standardize the controlled variables so that they do not influence the results. In our previous example, exposure to Agent Orange is the independent variable. It is hypothesized to cause a change in health (likelihood of having children with birth defects or developing a disease), the dependent variable. Many other things could affect health, including diet, exercise, and family history. These are the controlled variables.

There are two main types of scientific studies: experimental studies (manipulative experiments) and observational studies.

In a manipulative experiment, the independent variable is altered by the scientists, who then observe the response. In other words, the scientists apply a treatment. An example would be exposing developing mice to TCDD and comparing the rate of birth defects to a control group. The control group is group of test subjects that are as similar as possible to all other test subjects, with the exception that they don't receive the experimental treatment (those that do receive it are known as the experimental, treatment, or test group). The purpose of the control group is to establish what the dependent variable would be under normal conditions, in the absence of the experimental treatment. It serves as a baseline to which the test group can be compared. In this example, the control group would contain mice that were not exposed to TCDD but were otherwise handled the same way as the other mice (figure \(\PageIndex{e}\))

Figure \(\PageIndex{e}\): Laboratory mice. In a proper scientific study, the treatment would be applied to multiple mice. Another group of mice would not receive the treatment (the control group). Image by Aaron Logan (CC-BY).

In an observational study, scientists examine multiple samples with and without the presumed cause. An example would be monitoring the health of veterans who had varying levels of exposure to Agent Orange.

Scientific studies contain many replicates. Multiple samples ensure that any observed pattern is due to the treatment rather than naturally occurring differences between individuals. A scientific study should also be repeatable, meaning that if it is conducted again, following the same procedure, it should reproduce the same general results. Additionally, multiple studies will ultimately test the same hypothesis.

Results

Finally, the data are collected and the results are analyzed. As described in the Math Blast chapter, statistics can be used to describe the data and summarize data. They also provide a criterion for deciding whether the pattern in the data is strong enough to support the hypothesis.

The manipulative experiment in our example found that mice exposed to high levels of 2,4,5-T (a component of Agent Orange) or TCDD (a contaminant found in Agent Orange) during development had a cleft palate birth defect more frequently than control mice (figure \(\PageIndex{f}\)). Mice embryos were also more likely to die when exposed to TCDD compared to controls.

Figure \(\PageIndex{f}\): Cleft lip and palate, a birth defect in which these structures are split. Image by James Heilman, MD (CC-BY-SA).

An observational study found that self-reported exposure to Agent Orange was positively correlated with incidence of multiple diseases in Korean veterans of the Vietnam War, including various cancers, diseases of the cardiovascular and nervous systems, skin diseases, and psychological disorders. Note that a positive correlation simply means that the independent and dependent variables both increase or decrease together, but further data, such as the evidence provided by manipulative experiments is needed to document a cause-and-effect relationship. (A negative correlation occurs when one variable increases as the other decreases.)

Conclusion

Lastly, scientists make a conclusion regarding whether the data support the hypothesis. In the case of Agent Orange, the data, that mice exposed to TCDD and 2,4,5-T had higher frequencies of cleft palate, matches the prediction. Additionally, veterans exposed to Agent Orange had higher rates of certain diseases, further supporting the hypothesis. We can thus accept the hypothesis that Agent Orange increasesthe incidence of birth defects and disease.

In practice, the scientific method is not as rigid and structured as it might first appear. Sometimes an experiment leads to conclusions that favor a change in approach; often, an experiment brings entirely new scientific questions to the puzzle. Many times, science does not operate in a linear fashion; instead, scientists continually draw inferences and make generalizations, finding patterns as their research proceeds (figure \(\PageIndex{g}\)). Even if the hypothesis was supported, scientists may still continue to test it in different ways. For example, scientists explore the impacts of Agent Orange, examining long-term health impacts as Vietnam veterans age.

Figure \(\PageIndex{g}\): The scientific method is a series of defined steps that include experiments and careful observation. The steps are as follows: make an observation; ask a question; form a hypothesis that answers the question; make a prediction based on the hypothesis; do an experiment to test the prediction; analyze the results; and report the results. Whether the hypothesis is supported or not supported, the results are still reported. If a hypothesis is not supported by data, a new hypothesis can be proposed.

Scientific findings can influence decision making. In response to evidence regarding the effect of Agent Orange on human health, compensation is now available for Vietnam veterans who were exposed to Agent Orange and develop certain diseases. The use of Agent Orange is also banned in the U.S. Finally, the U.S. has began cleaning sites in Vietnam that are still contaminated with TCDD.

Building on the Work of Others

Only rarely does a scientific discovery spring full-blown on the scene. When it does, it is likely to create a revolution in the way scientists perceive the world around them and to open up new areas of scientific investigation. Darwin's theory of evolution and Mendel's rules of inheritance are examples of such revolutionary developments. Most science, however, consists of adding another brick to an edifice that has been slowly and painstakingly constructed by prior work.

The development of a new technique often lays the foundation for rapid advances along many different scientific avenues. Just consider the advances in biology that discovery of the light microscope and, later, the electron microscope have made possible. Throughout these pages, there are many examples of experimental procedures. Each was developed to solve a particular problem. However, each was then taken up by workers in other laboratories and applied to their problems.

In a similar way, the creation of a new explanation (hypothesis) in a scientific field often stimulates workers in related fields to reexamine their own field in the light of the new ideas. Darwin's theory of evolution, for example, has had an enormous impact on virtually every subspecialty in biology as well as environmental science. To this very day, scientists in specialties as different as biochemistry and conservation biology are guided in their work by evolutionary theory (figure \(\PageIndex{g}\)).

Figure \(\PageIndex{h}\): Understanding the endangered mountain yellow-legged frog through the lens of evolution and genetics has aided its conservation. Image by Iasaac Chellman/NPS (CC-BY).

References

Institute of Medicine (US) Committee to Review the Health Effects in Vietnam Veterans of Exposure to Herbicides. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington (DC): National Academies Press (US); 1994. 2, History of the Controversy Over the Use of Herbicides.

Neubert, D., Dillmann, I. Embryotoxic effects in mice treated with 2,4,5-trichlorophenoxyacetic acid and 2,3,7,8-tetrachlorodibenzo-p-dioxin. Naunyn-Schmiedeberg's Arch. Pharmacol. 272, 243-264 (1972).

Stellman, J. M., & Stellman, S. D. (2018). Agent Orange During the Vietnam War: The Lingering Issue of Its Civilian and Military Health Impact. American journal of public health, 108(6), 726-728.

Yi, S. W., Ohrr, H., Hong, J. S., & Yi, J. J. (2013). Agent Orange exposure and prevalence of self-reported diseases in Korean Vietnam veterans. Journal of preventive medicine and public health = Yebang Uihakhoe chi, 46(5), 213-225.

Attributions

Modified by Melissa Ha from the following sources:

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This section reviews the scientific method and discusses why it is so important to the the process of science. The main steps of the scientific method are observation, question, hypothesis, ...

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A-level Environmental Science 7447 | Assessment Resources | AQA

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A-level Environmental Science 7447 | Assessment Resources | AQA

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A-Level Environmental Science AQA – Revision Content

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A-Level Environmental Science AQA – Revision Content

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Free A Level Environmental Science AQA Revision Content — Study Rocket

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Browse hundreds of lessons for A Level Environmental Science AQA to study for free with assessment questions, text & videos.

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AQA A-Level Environmental Science Revision

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AQA A-Level Environmental Science Revision

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AQA A Level Environmental Science Revision

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Revision notes, past papers and practice questions for AQA A Level Environmental Science, written by our expert team of teachers and examiners.

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This is The Crown Estate Open Data Portal. Here you can access the publicly available information from The Crown Estate's Portfolios.

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World Energy Outlook 2025 – Analysis - IEA

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World Energy Outlook 2025 - Analysis and key findings. A report by the International Energy Agency.

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SPC-EU Deep Sea Minerals Project - Brochures

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SPC-EU Deep Sea Minerals Project, SOPAC, SPC

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In 2001, scientists predicted the Earth would warm by 1.4 - 5.8C by 2100.

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The National Grid is the electric power transmission network for Great Britain

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The rise of wind

Great Britain's exposed position in the north-east Atlantic makes it one of the best locations in the world for wind power, and the shallow waters of the North Sea host several of the world's largest offshore wind farms.

New wind power records are set regularly, and between 6:30pm and 7:00pm on 10th January 2023 British wind farms averaged a record 21.69GW of generation.

About this site

This site is an open source project by Kate Morley. I've published the code on GitHub under the terms of the Creative Commons CC0 1.0 Universal Legal Code. This means I've waived all copyright and related rights to the extent possible under law, with the intention of dedicating the code to the public domain. You can use and adapt it without attribution.

If you'd like to thank me for the time I've spent working on this project, or help me cover the costs of hosting a site that receives over 8,000,000 visits each year, I do accept donations.

The data comes from National Grid ESO's Data Portal, Elexon's Balancing Mechanism Reporting Service, and the Carbon Intensity API (a project by National Grid ESO and the University Of Oxford Department Of Computer Science).

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Shows the live status of Great Britain's electric power transmission network

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GB Renewable percentage of total Generation

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Rich countries today live in a high energy society. These countries have extensive energy infrastructure (like the electrical grid) to give citizens access to energy currencies which provide extensive services that allow them to maintain a high quality of life.

People living in wealthy countries have:

Reliable sources of electricity that turn on whenever they wish and can use functionally as much of this electricity as they like.

Extensive transportation fuels for personal transport and the transportation of goods (like food, clothing, etc.) where there is, once again, functionally as much of these secondary fuels as people would like to buy.

Home heating (and commercial heating) systems that actively control temperatures in buildings within a narrow range, which people can set for their own comfort.

Extensive refrigeration for food preservation

Access to a wide range of goods and services provided by and maintained by the above energy infrastructure. Moreover, the price of energy is usually a small fraction of a household's total expenditure.

All of these provide comfort and economic opportunities. Many of the non-OECD countries are developing infrastructure to create the opportunities available in these wealthy OECD countries. Most notably the BRIC countries are increasing primary energy use quite rapidly.

One grouping of these wealthy countries is the group of OECD countries. The OECD countries contain roughly 1/6th of the world population, but use roughly 1/2 of the primary energy. This means that the more than 6 billion people living in non-OECD countries use roughly the same amount of energy as slightly more than 1 billion living in the OECD countries. See figure 2 for a comparison of their energy use per person (and click the button to see total energy use). To see a map of which countries are in the OECD, please see figure 1.

Figure 2. Primary energy use in OECD (blue) and non-OECD (red) countries. Click the 'per capita' to see total energy use of these countries, see the map in figure 2 for which countries are part of OECD.

References

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Rich countries today live in a high energy society. These countries have extensive energy infrastructure (like the electrical grid) to give citizens access to energy currencies which provide extensive services that allow them to maintain a high quality of life.

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Energy from primary energy sources almost always transformed into different forms to make it easier to use, transport, or store. These forms are called energy currencies. Several authors have introduced the idea of energy currency as a way to think about these useful intermediate forms of energy.

Humans harvest primary energy from nature and eventually turn this energy into an energy service. Primary energy sources include primary energy flows (like solar power) and primary fuels (like raw natural gas). The energy service is what maintains a high energy society (through heating, transportation, etc.). These intermediate forms, energy currencies, are used because they are flexible and transportable energy, which allows moving the energy supply almost anywhere. For example, while it's nice to enjoy sunlight, it doesn't recharge the battery in a cell phone; some energy conversion technology is required to get it into the specific form (and then moved with energy distribution technology, like pipelines or the electrical grid). The form that holds that energy from the energy conversion technology is sometimes referred to as an energy currency. There is always some energy loss when making an energy currency, often due to the second law of thermodynamics.

Electricity, consumer natural gas and gasoline are the most relevant energy currencies, and are derived from primary energy. These energy currencies are easier to turn into useful work than most primary energy is. For example, a lump of coal can be burned for lighting a house, but it's much cleaner (at least for the living room) to burn that lump of coal in a power plant and send the electricity through the grid to the house.

Energy currencies are flexible; they can be used for many energy services. For example, electricity is far more flexible than wind power. When an electric kettle boils water, the water boils no differently whether the electricity came from coal, nuclear, biomass, wind, or hydro. The electricity could have also been used to play a computer game. See more in the article electricity as an energy currency.

This flexibility of use means that, in general, the amount of energy currency that the world uses is growing faster than primary energy use is. In other words, the percentage of energy use that goes to electricity is rising (electricity use is rising faster than energy use). Worldwide, more and more energy is being turned into energy currencies because of how useful they are. Visit the article on trends in energy currencies for more information.

Examples of Energy Currency

Electricity

The most relevant energy currency in society is electricity. Electricity is flexible, easy to use for just about anything, and is made specifically for the transportation and use of energy. Electricity will never run out because the electrons aren't getting used up; they're just carrying energy by moving. More energy can always be put into the same electrons over and over again, and taken out to use for more energy services.

Oil Products

Gasoline, diesel and kerosene are energy currencies as well. While these are not as flexible as electricity, they are an intermediate form of energy that is produced specifically to enable easy use of the stored chemical energy.

Many people are talking about using molecular hydrogen as an energy currency (that's hydrogen as a molecule, rather than hydrogen as an atom), with the thought that hydrogen will become an increasingly important energy currency (and some disagree).

Natural Gas

The idea of an energy currency gets more confusing with natural gas. Natural gas is used with very minimal processing, the distinction between raw natural gas and consumer natural gas isn't talked about much. That being said, raw natural gas still must undergo natural gas processing at a natural gas processing plant. Raw natural gas is extracted from the ground and would be a primary fuel. Consumer natural gas is used for heating or for vehicles that use natural gas to operate. Natural gas is quite flexible and is used for (among many possibilities): electricity generation, home heating, and cooking.

In summary, when extracted from the ground, before it's processed, natural gas (raw natural gas) is primary, but the gas delivered for use by consumers (consumer natural gas) is an energy currency.

Nuclear Fuel

Nuclear fuel is not considered an energy currency even though it is considered a secondary fuel. Nuclear fuel is a secondary fuel because nuclear power plants cannot use raw uranium ore as fuel; the ore needs to be processed into fuel pellets. Nuclear fuel is an intermediate form of energy which makes it easier to use. This form of fuel is quite inflexible; nuclear fuel usually has to be put into a specific type of nuclear reactor, and not just any reactor will do! This means that while an intermediate form, it's not an energy currency, because it provides electricity (and perhaps heat someday) but the nuclear fuel itself is not used to provide energy services (like space heating, transportation, etc.).

For Further Reading

References

1. This drawing was made by Xining Chen for this website in August 2014 and is used with her permission.

2. McMahon, Emperor's New Hydrogen Economy, 1st edition. iUniverse, Inc., 2006

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Energy from primary energy sources almost always transformed into different forms to make it easier to use, transport, or store. These forms are called energy currencies. Several authors have introduced the idea of energy currency as a way to think about these useful intermediate forms of energy.

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A primary energy flow (or within the energy education site primary flow or just flow) refers to natural processes with energy that can be extracted and transformed in a useful way. Primary energy flows include solar radiation shining on the Earth from the Sun, or water flowing downstream in a river. The energy in these primary flows can be harnessed to provide energy services such as home heating, transportation and electrical generation.

Primary energy flows are one of two broad types of energy humans harvest from nature ( primary energy), the other being primary fuels. Just like with primary fuels, most of the energy in the Earth's primary energy flows come either directly from the Sun or indirectly from the Sun (see Earth's energy flow). Primary flows tend to be diffuse (low energy density) which can lead to surprising environmental impacts. It is difficult to compare the energy density or environmental impact of primary flows to fuels (see primary fuel vs. primary flow). When people talk about energy conservation, usually they mean using less of the energy from these primary flows or fuels (see fuel conservation).

Primary energy flows include harnessing wind power, solar power (both photovoltaic and solar thermal), hydropower, wave power, tidal power and geothermal power. Because flows take advantage of energy in Earth's systems, flows tend to replenish their energy supply. This is why flows are usually thought of as renewable, and often sustainable (see renewable and sustainable energy). Despite this, it is possible to use primary flows unsustainably, which has specifically been a problem with geothermal energy.

At the moment energy accounting only keeps track of primary flows that are used for harnessing power for power's sake like generating electricity. There's a fair amount of power taken from primary flows that don't get formally accounted for. For example sailing ships use wind and many ships using tides (which is different from the electrical generation of tidal power). The largest flow used is of course sunlight, and the biggest way that's used is by keeping the Earth at a comfortable living temperature.

The amount of energy from sunlight is enormous, but mostly it goes towards keeping the atmosphere at a livable temperature, evaporating water for the hydrologic cycle and driving wind. Because this total flow of solar energy is thousands of times greater than the total energy use by humans many people advocate for using more solar energy. The difficulty with this energy is that it's delivered over a very wide area (it's very diffuse) and impossible (and expesnive) to catch it all, but it is there.

By formal reckoning, primary flows provide only a small fraction (~5%) of today's primary energy, see figure 1. Almost all of this energy is going into electricity generation. Due to peculiarities of thermodynamics, primary flows generate practically no waste heat (using fuels in a heat engine creates waste heat). All the energy successfully harvested from the primary flow is used for generating electricity (see Betz limit for why not all of the energy can be harvested for wind power). This means that despite being only ~5% of the primary energy, flows make up ~20% of electrical generation, the bulk of which is hydro and with wind being the second largest contributor. Different countries have very different energy mixes, please see electricity generation for a detailed map of where different countries get their electricity from.

Figure 1. Only a small fraction, shown as the extracted pie pieces, of the world's energy comes from primary flows. Most of this energy comes from hydropower, although a small fraction is wind power, solar power, geothermal energy, and tidal power. Since primary flows usually go into electricity, the percent of electricity generated by primary flows is ~20% (still mostly hydro) because flows don't have the same limitations of having a thermal efficiency's that heat engines have and flows are used almost entirely for electricity generation.

Potential confusion

People occasionally confuse energy flows with other concepts that are related:

Electricity is flowing energy, but it is not a flow in this sense. Electricity is produced through energy transformations from primary energy. It's not itself a primary energy form but an energy currency.

Heat is flowing energy. Specifically, it's thermal energy flowing from hot to cold. This is tricky, because there are times when heat can be considered a primary energy source, when taking geothermal energy from the ground. Likewise, when using the Sun's heat, that would be a flow. When something is merely hot and giving off heat, like a fire, that's not a flow.

There are also material flows, which aren't energy at all. This refers to how certain materials, like metals, move through the world's economy. This isn't primary energy, so it's not a flow.

References

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A primary energy flow (or within the energy education site primary flow or just flow) refers to natural processes with energy that can be extracted and transformed in a useful way. Primary energy flows include solar radiation shining on the Earth from the Sun, or water flowing downstream in a river.

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Fuels are dense repositories of energy that are consumed to provide energy services such as heating, transportation and electrical generation. Even though most fuels ultimately get their energy from the sun (see energy conservation) they are usually considered to be a primary energy source. When people talk about energy conservation, usually they mean using less fuel (see fuel conservation).

Almost all, about 95%, of human primary energy comes from primary fuels (as opposed to primary energy flows). These fuels go into power plants, see figure 1, engines, heaters and anything else that humans derive work or heat from. This percentage is slightly different for electrical generation; 85% of the primary energy to generate electricity comes from fuels (as opposed to primary energy flows).

Types of fuel

When a fuel is used, it undergoes some process that leaves it in a form with less energy. This means that most fuels are non-renewable, but may be found extensively enough as to be considered sustainable. Primary flows, like wind, are not considered fuels and are a class of primary energy supply entirely different from fuels - for more information on this difference please visit the page: fuel vs flow.

Primary fuels include nuclear fuels, biofuels and fossil fuels. Often primary fuels are processed to make something chemically distinct from how they were harvested from a natural resource. For example crude oil is a primary fuel that undergoes fractional distillation to become products more useful to the consumer.

Gasoline, kerosene and diesel are also fuels, but are different as they are derived from primary energy sources. These are secondary fuels as opposed to primary fuels. These secondary fuels were processed from the form found as a natural resource and can also be considered energy currencies. Secondary fuels are easier for engines to burn, so are often made from crude oil as a way of getting the most energy out as possible.

Furthermore, fuels like methane, butane and propane are found mixed together in their natural resource (which would be the primary energy source) and are separated during the fractional distillation process.

Hydrogen is a fuel that can be obtained chemically from water or methane (and other sources as well), it is considered an energy currency as it doesn't form naturally in any abundance on Earth.

Fuels vary considerably in energy density, cost, and environmental impact, for example uranium has a significantly higher energy density than fossil fuels but is much more expensive. It is also difficult to compare the energy density and environmental impact of fuels to primary flows due to the nature of how each is utilized.

Different countries have very different energy mixes, please see electricity generation for a detailed map of where different countries get their electricity from. Below is a pie chart showing the world's energy production, with fuels shown as the slices that are not extracted from the graph.

Approximately 95% percent of the primary energy in the world comes from fuels like oil, coal and natural gas (all of which except nuclear fuels produce extensive greenhouse gases when used). Most of the rest of the world's primary energy comes from hydropower, although a small fraction is wind power, solar power, geothermal energy, and tidal power. The amount of electricity that comes from flows increases to about 19% (still mostly hydro) because flows don't have the same limitations of thermal efficiency as heat engines, and flows are used almost entirely for electricity generation.

For Further Reading

References

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Fuels are dense repositories of energy that are consumed to provide energy services such as heating, transportation and electrical generation. Even though most fuels ultimately get their energy from the sun (see energy conservation) they are usually considered to be a primary energy source.

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For most of human history, our ancestors relied on very basic forms of energy: human muscle, animal muscle, and the burning of biomass such as wood or crops. But the Industrial Revolution unlocked a whole new energy resource: fossil fuels. Fossil energy has been a fundamental driver of the technological, social, economic, and development progress that has followed.

Fossil fuels (coal, oil, gas) have, and continue to, play a dominant role in global energy systems.

But they also come with several negative impacts. When burned, they produce carbon dioxide (CO ₂) and are the largest driver of global climate change. They are also a major contributor to local air pollution, which is estimated to be linked to millions of premature deaths each year.

As low-carbon sources of energy - nuclear and renewables - become readily available, the world needs to rapidly transition away from fossil fuels.

This article presents the long-run and recent perspectives on coal, oil, and gas - how much countries produce and consume, where our fossil fuel reserves are, and what role the fuels play in our energy and electricity systems.

Fossil fuel consumption

Global fossil fuel consumption

The burning of fossil fuels for energy began around the Industrial Revolution. But fossil fuel consumption has changed significantly over the past few centuries - both in terms of what and how much we burn.

In the interactive chart, we see global fossil fuel consumption broken down by coal, oil, and gas since 1800. Earlier data, pre-1965, is sourced from Vaclav Smil's work on energy transitions; this has been combined with data published in BP's Statistical Review of World Energy from 1965 onwards.

Fossil fuel consumption has increased significantly over the past half-century, around eight-fold since 1950 and roughly doubling since 1980.

But the types of fuel we rely on have also shifted from solely coal towards a combination with oil and gas. Today, coal consumption is falling in many parts of the world. But oil and gas are still growing quickly.

Fossil fuel consumption: which countries use the most energy from fossil fuels?

We've looked at how much fossil fuel energy is consumed globally. But what about countries? How much fossil energy do they consume?

The interactive chart here shows the amount of primary energy from fossil fuels that is consumed each year.

This is the sum of energy from coal, oil, and gas. In the sections below, we look at each of these sources individually.

Per capita: where do people consume the most energy from fossil fuels?

Looking at energy consumption at the country level is often a strong reflection of population size rather than actual fossil fuel consumption per person.

How do these comparisons look when we adjust for population?

In the interactive chart we see the amount of energy from fossil fuels consumed per person. This is the sum of primary energy from coal, oil, and gas combined.

Across the world, we see that the largest consumers use more than ten times the amount of fossil energy than some of the smallest consumers.

Fossil fuel consumption by type

In the sections above, we looked at the consumption of fossil fuels collectively. But it's important to look at the role of coal, oil, and gas individually - their impacts are not equal. Coal, for example, typically produces more CO ₂ and local air pollution per unit of energy [see our article on the relative safety and impacts of different energy sources].

In the interactive charts here, we show fossil fuel consumption disaggregated by type. This is shown as a stacked area chart - useful for seeing the relative contribution of each; but also as a line chart which allows us to see how the consumption of each is changing over time.

Fossil fuels in the energy and electricity mix

What share of primary energy comes from fossil fuels?

How do fossil fuels fit in within the rest of the energy mix? What share of primary energy comes from fossil fuels?

Around four-fifth of global primary energy comes from coal, oil, and gas. Over the coming decades, we must rapidly reduce this share by displacing them with low-carbon energy sources.

In the interactive chart, we see how this share varies across the world.

What share of electricity comes from fossil fuels?

Electricity is one component of total energy consumption - the other two being transport and heating.

Globally, fossil fuels account for a much smaller share of electricity production than the energy system as a whole.

This interactive map shows the share of electricity that comes from fossil fuels (coal, oil, and gas summed together) across the world. Oil accounts for only a small share of electricity production - most come from coal and gas. The share from coal and gas individually can be found in the sections below.

Coal

Coal production: how much do countries produce?

Which countries produce the most coal? How has this changed over time?

In the interactive chart here we see coal production by country. This has been converted into primary energy equivalents (i.e., terawatt-hours of energy) for comparability across our other data on energy.

Note that this measures coal production, not consumption. Many countries consume energy from coal in their energy supply. However, not all countries have coal reserves to produce this themselves. This therefore measures coal production before trade between countries.

Energy from coal: how much do countries consume?

Fossil fuel production is an important metric - it helps us understand where fossil fuels are being extracted. But we also care about where that energy is being consumed - that tells us what role fossil fuels are playing in the energy system of each country.

This interactive chart shows primary energy consumption from coal across the world. This represents coal production adjusted for trade (so, coal exports are subtracted and imports are added).

What share of primary energy comes from coal?

Coal has been a critical energy source and a mainstay in global energy production for centuries.

But it's also the most polluting energy source: both in terms of the amount of CO ₂ it produces per unit of energy, but also the amount of local air pollution it creates. Moving away from coal energy is important for climate change and human health.

This interactive map shows the share of primary energy from coal worldwide.

What share of electricity comes from coal?

Coal is currently the largest source of electricity globally. For many countries remains the dominant source. But, we also see that others have seen a massive shift away from coal in recent years - the UK is one such example.

This interactive map shows the share of electricity that comes from coal worldwide.

When do countries plan to phase out coal?

Coal is the world's oldest industrial source of energy. It is still a dominant source of energy across the world today - especially within our electricity mix.

But coal is the world's dirtiest fuel - it not only emits the most carbon dioxide emissions per unit of energy, it severely impacts health through air pollution.

Many countries are committing to phasing coal power out of their electricity mix. This map shows countries' pledges to achieve this. Some countries are already coal-free. Some have set to phase it out by 2030, 2040, or later. Some have not yet committed to eliminating it.

Oil

Oil production: how much do countries produce?

Which countries produce the most oil? How has this changed over time?

In the interactive chart here we see oil production by country. This has been converted into primary energy equivalents (i.e., terawatt-hours of energy) for comparability across our other data on energy.

Note that this measures oil production, not consumption. Many countries consume energy from oil in their energy supply. However, not all countries have oil reserves to produce this themselves. This therefore measures oil production before trade between countries.

Energy from oil: how much do countries consume?

Oil production is an important indicator to follow - it helps us understand where it's being extracted, who the main oil producers are, and how this relates to oil reserves. But we also care about where that oil is being consumed - that tells us what role it's playing in the energy system of each country.

This interactive chart shows primary energy consumption from oil across the world. This represents oil production adjusted for trade (so, oil exports are subtracted and imports are added).

What share of primary energy comes from oil?

Oil is the world's largest energy source today. It is the dominant source of energy for the transport sector in particular.

This interactive map shows the share of primary energy from oil worldwide.

Gas

Gas production: how much do countries produce?

Which countries produce the most gas? How has this changed over time?

In the interactive chart here we see gas production by country. This has been converted into primary energy equivalents (i.e., terawatt-hours of energy) for comparability across our other data on energy.

Note that this measures gas production, not consumption. Many countries consume energy from gas in their energy supply. But not all countries have gas reserves to produce this themselves. This therefore measures gas production before trade between countries.

Energy from gas: how much do countries consume?

In the section above we looked at where in the world gas is produced. But, after trade, where in the world is gas consumed?

This interactive chart shows primary energy consumption from gas across the world. This represents gas production adjusted for trade (so, gas exports are subtracted and imports are added).

What share of primary energy comes from gas?

Natural gas has, for decades, lagged behind coal and oil as an energy source. But today, its consumption is growing rapidly - often as a replacement for coal in the energy mix. Gas is a major provider of electricity production and a key source of heat.

This interactive map shows the share of primary energy from gas worldwide.

What share of electricity comes from gas?

Gas is now the second largest source of electricity production globally.

Its contribution is growing quickly in many countries as they substitute it for coal in the electricity mix. From a climate perspective, this transition is positive since gas typically emits less CO per unit of energy. But, we still ultimately want to shift away from gas towards low-carbon sources such as renewables and nuclear.

Gas is now the second largest source of electricity production globally.

Its contribution is growing quickly in many countries as they substitute it for coal in the electricity mix. From a climate perspective, this transition is positive since gas typically emits less CO per unit of energy. But, we still ultimately want to shift away from gas towards low-carbon sources such as renewables and nuclear.

This interactive map shows the share of electricity that comes from gas worldwide.

Fossil fuel reserves

Coal reserves

In previous sections, we examined how much fossil fuels different countries produced or consumed. But where in the world do our existing reserves of fossil fuels remain?

Which countries have the potential to extract and sell them?

In the interactive chart, we see proven coal reserves across the world.

It's important to distinguish reserves versus resources here. "Proven reserves" represent coal that we know with reasonable certainty could be recovered in the future under existing economic and technological operating conditions. In other words, we know it's there, and it would be technologically and economically feasible to extract it.

Reserves represent only some fraction of resources, however; we continue to discover new quantities of coal, and with time more becomes technologically feasible to extract. This means our quantity of reserves changes all the time - not only based on how much we consume, but by how many new resources are 'unlocked'.

Gas reserves

Where in the world do we have gas reserves? Which countries have the ability to extract, consume, and trade?

In the interactive chart, we see proven gas reserves across the world.

It's important to distinguish reserves versus resources here. "Proven reserves" represent coal that we know with reasonable certainty could be recovered in the future under existing economic and technological operating conditions. In other words, we know it's there, and it would be technologically and economically feasible to extract it.

Reserves represent only some fraction of resources, however; we continue to discover new quantities of gas, and with time more becomes technologically feasible to extract. This means our quantity of reserves changes all the time - not only based on how much we consume, but by how many new resources are 'unlocked'.

We look at the difference between reserves and resources in more detail .

Definitions and measurement

Reserves vs. resources: when does a resource become a reserve?

The terms "reserves" and "resources" are often used interchangeably. However, there is an important distinction between the two. The chart explains this distinction visually.

Every reserve is indeed a resource, but not every resource is a reserve. Two requirements determine whether a mineral resource becomes a reserve. The first is the degree of certainty that it exists: the planet likely has many mineral resources that we have not yet discovered. So to be defined as a reserve, we must have either a proven, probable, or possible understanding of its existence. The second criterion relates to the economic feasibility of being able to access and extract the mineral resource. To be defined as a reserve, it must be economically and technologically viable to recover. If the economics are subeconomic (i.e. would result in a net loss) or marginal, a mineral resource is not defined as a reserve.

Whilst the original source of this concept - the American geologist Vincent McKelvey - visualized it as a static box, this transition between resources and reserve classifications is dynamic. As we discover previously unknown resources and develop improved extraction technologies for economic recovery, this reserve box can grow with time (or shrink as we consume them).

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Fossil fuels were key to industrialization and rising prosperity, but their impact on health and the climate means that we should transition away from them.

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Matteo Barbarino, IAEA Department of Nuclear Sciences and Applications

Nuclear fusion is the process by which two light atomic nuclei combine to form a single heavier one while releasing massive amounts of energy.

Fusion reactions take place in a state of matter called plasma - a hot, charged gas made of positive ions and free-moving electrons with unique properties distinct from solids, liquids or gases.

The sun, along with all other stars, is powered by this reaction. To fuse in our sun, nuclei need to collide with each other at extremely high temperatures, around ten million degrees Celsius. The high temperature provides them with enough energy to overcome their mutual electrical repulsion. Once the nuclei come within a very close range of each other, the attractive nuclear force between them will outweigh the electrical repulsion and allow them to fuse. For this to happen, the nuclei must be confined within a small space to increase the chances of collision. In the sun, the extreme pressure produced by its immense gravity creates the conditions for fusion.

Why are the scientists studying fusion energy?

Ever since the theory of nuclear fusion was understood in the 1930s, scientists - and increasingly also engineers - have been on a quest to recreate and harness it. That is because if nuclear fusion can be replicated on earth at an industrial scale, it could provide virtually limitless clean, safe, and affordable energy to meet the world's demand.

Fusion could generate four times more energy per kilogram of fuel than fission (used in nuclear power plants) and nearly four million times more energy than burning oil or coal.

Most of the fusion reactor concepts under development will use a mixture of deuterium and tritium - hydrogen atoms that contain extra neutrons. In theory, with just a few grams of these reactants, it is possible to produce a terajoule of energy, which is approximately the energy one person in a developed country needs over sixty years.

Fusion fuel is plentiful and easily accessible: deuterium can be extracted inexpensively from seawater, and tritium can potentially be produced from the reaction of fusion generated neutrons with naturally abundant lithium. These fuel supplies would last for many thousands of years. Future fusion reactors are also intrinsically safe and are not expected to produce high activity or long-lived nuclear waste. Furthermore, as the fusion process is difficult to start and maintain, there is no risk of a runaway reaction and meltdown; fusion can only occur under strict operational conditions, outside of which (in the case of an accident or system failure, for example), the plasma will naturally terminate, lose its energy very quickly and extinguish before any sustained damage is done to the reactor.

Importantly, nuclear fusion - just like fission - does not emit carbon dioxide or other greenhouse gases into the atmosphere, so it could be a long-term source of low-carbon electricity from the second half of this century onwards.

Hotter than the sun

While the sun's massive gravitational force naturally induces fusion, without that force a temperature even higher than in the sun is needed for the reaction to take place. On Earth, we need temperatures of over 100 million degrees Celsius to make deuterium and tritium fuse, while regulating pressure and magnetic forces at the same time, for a stable confinement of the plasma and to maintain the fusion reaction long enough to produce more energy than what was required to start the reaction.

While conditions that are very close to those required in a fusion reactor are now routinely achieved in experiments, improved confinement properties and stability of the plasma are still needed to maintain the reaction and produce energy in a sustained manner. Scientists and engineers from all over the world continue to develop and test new materials and design new technologies to achieve net fusion energy.

See more information in the following video:

The Future of Fusion Energy

Where do we stand on fusion technology development?

Nuclear fusion and plasma physics research are carried out in more than 50 countries, and fusion reactions have been successfully produced in many experiments, albeit without so far generating more energy than what was required to start the reaction process. Experts have come up with different designs and magnet-based machines in which fusion takes place, like stellarators and tokamaks, but also approaches that rely on lasers, linear devices and advanced fuels.

How long it will take for fusion energy to be successfully rolled out will depend on mobilizing resources through global partnerships and collaboration, and on how fast the industry will be able to develop, validate and qualify emerging fusion technologies. Another important issue is to develop in parallel the necessary nuclear infrastructure, such as the requirements, standards, and good practices, relevant to the realisation of this future energy source.

Following 10 years of component design, site preparation, and manufacturing across the world, the assembly of ITER in France, the world's largest international fusion facility, commenced in 2020. ITER is an international project that aims to demonstrate the scientific and technological feasibility of fusion energy production and prove technology and concepts for future electricity-producing demonstration fusion power plants, called DEMOs. ITER will start conducting its first experiments in the second half of this decade and full-power experiments are planned to commence in 2036.

DEMO timelines vary in different countries, but the consensus among experts is that an electricity-producing fusion power plant could be built and operating by 2050. In parallel, numerous privately funded commercial enterprises are also making strides in developing concepts for fusion power plants, drawing on the know-how generated over years of publicly funded research and development, and proposing fusion power even sooner.

What is the role of the IAEA?

The IAEA has a long history of being at the core of international fusion research and development, and recently started supporting early technology development and deployment

The IAEA launched the Nuclear Fusion journal in 1960 to exchange information about advances in nuclear fusion. The journal is now considered the leading periodical in the field. The IAEA also regularly publishes TECDOCs and outreach and educational material on fusion.

The first international IAEA Fusion Energy Conference was held in 1961 and, since 1974, the IAEA convenes a conference every two years to foster discussion on developments and achievements in the field. See a short film about the history of this conference series

Since 1971, the IAEA International Fusion Research Council has served as a catalyst for establishing improved international collaboration in fusion research.

The ITER Agreement is deposited with the IAEA Director General. Collaboration between the IAEA and the ITER Organization is formalized through a cooperation agreement in 2008, which was expanded and deepened in 2019.

The IAEA facilitates international cooperation and coordination on DEMO programme activities around the world.

The IAEA implements a series of technical meetings and coordinated research activities on topics relevant to fusion science and technology development and deployment, and organizes and supports education and training activities on fusion.

The IAEA maintains numerical databases of fundamental data for fusion energy research, as well as the Fusion Device Information System (FusDIS), which compiles information on fusion devices operating, under construction or being planned around the world.

The IAEA is carrying out a project on synergies in technology development between nuclear fission and fusion for energy production, and on the long-term sustainability - including the handling of radioactive waste - and legal and institutional issues for fusion facilities.

The IAEA is investigating key safety aspects covering the whole lifecycle of fusion facilities, where guidelines and specific reference documents are needed.

The IAEA is supporting a pre-feasibility study of a generic fusion demonstration plant.

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Matteo Barbarino, IAEA Department of Nuclear Sciences and Applications Nuclear fusion is the process by which two light atomic nuclei combine to form a single heavier one while releasing massive amounts of energy. Fusion reactions take place in a state of matter called plasma - a hot, charged gas made of positive ions and free-moving electrons with unique properties distinct from solids, liquids or gases.

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Nuclear Power in the World Today - World Nuclear Association

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There are about 440 commercial nuclear power reactors operable in about 30 countries, with about 390 GWe of total capacity. About 60 more reactors are under construction. Over 50 countries operate a total of about 220 research reactors and a further 180 nuclear reactors power around 140 ships and submarines.

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Have you ever thought about where the energy you use on a daily basis - the energy to charge your phone, turn the heating on and get to school - comes from? Read on to find out how we collect primary energy from all around us.

All of these primary energy sources can be mixed and matched depending on their availability and what we need to use the energy for. The way we mix and match the use of these sources of energy is known as the energy mix.

Primary energy sources are found in nature and have not yet been transformed into more convenient forms of energy. Secondary energy sources are made using primary energy sources, for example electricity is a secondary energy, generated by a number of primary sources. These are more convenient to use in our daily lives.

Fossil fuels Fossil fuels are specific types of non-renewable energy sources. Fossils refer to living organisms such as plants and animals that died hundreds of millions of years ago. The energy these organisms received from the sun through photosynthesis when alive is trapped and stored.

Over time, these organisms sank further and further into the ground, until the pressure and temperature transformed them into the fuels we use today; coal, oil and natural gas.

COAL

Coal

What is it used for? Electricity generation, heat and steel making.

Is it renewable? No, it is a finite fossil fuel.

How do we collect it? Underground mining, after which the coal is taken to a power station and burnt to produce steam, which then turns a turbine to generate electricity.

How much is left? Should last until 2120s if we keep using it the same way we do today.

Is it clean? No, it produces lots of air pollution, as well as the most carbon of all the energy sources.

Quick Fact: The Government recently announced that there will be no more coal-fired power stations by 2025.

OIL

Oil

What is it used for? Transport and manufacturing.

Is it renewable? No, it is a finite fossil fuel.

How do we collect it? Underground drilling to harness the oil, then heating the oil at different temperatures to separate the various types of oil for use in transport or manufacturing.

How much is left? The amount of oil that we can produce using today's technology will last until towards the end of this century if we keep using it the same way we do today. However, with technology developing all the time, as well as undiscovered resources around the world (including off the coast of the UK), oil could last a lot longer than this, past 2100.

Is it clean? No, it emits a large amount of CO ₂.

Quick Fact: Used to make all kinds of products like: medicine, car tires, bubble gum, glasses, and even cosmetics such as perfume and lipstick.

NATURAL GAS

Gas

What is it used for? Heating, cooking, electricity, manufacturing, agriculture, transport.

Is it renewable? No, it is a finite fossil fuel.

How do we collect it? Underground drilling, after then the natural gas can be used for heating and cooking, or transformed into electrical energy in a power station.

How much is left? Should last until towards the end of this century if we keep using it the same way we do today, but as with oil, new technology and undiscovered resources could extend this date even longer.

Is it clean? No, but it does emit the least amount of CO ₂ of all the fossil fuels, and it's clean-burning (meaning it gives off few air pollutants). Like any type of construction, emissions are produced when gas plants are built and during maintenance.

Quick Fact: Natural gas is actually a mixture of gases that can be separated out and used for different things such as propane sold in canisters for camping.

NUCLEAR

Nuclear

What is it used for? Electricity.

Is it renewable? No, although there is a large amount of uranium ore (which is used in nuclear power stations) in Australia and Canada.

How do we collect it? Electricity is generated through nuclear fission, which involves splitting atoms in a chain reaction, releasing heat energy which in turn produces steam. This steam turns a turbine which generates electricity.

How much is left? It is difficult to predict how much uranium is left, though it shows no signs of running out within our lifetime. Some reports state there is over 100 years of uranium that we know of. This also doesn't include other materials like thorium that can also be used in nuclear power stations.

Is it clean? Yes, although there is radioactive waste produced that needs to be safely stored. There are also emissions in the building and maintenance of nuclear power stations, as is the case when building any power stations, turbines and panels.

Quick Fact: It currently accounts for 20% of UK electricity demand, but this might increase to 40% by 2030.

WIND

Wind

What is it used for? Electricity.

Is it renewable? Yes.

How do we collect it? Wind turbines are placed onshore and offshore in suitably windy areas. The wind turns the turbines, generating electricity.

How much is left? Wind will not run out. Successful wind turbines are dependent on how windy the area is, and the bigger the turbine, the more electricity it can generate.

Is it clean? Yes, the only emissions are produced in building and installing the wind turbines, as there are with the construction of any power station or solar panel.

Quick Fact: UK is currently 6th in wind energy global ranking due to its location.

SOLAR

Solar

What is it used for? Heating, cooking and electricity.

Is it renewable? Yes.

How do we collect it? Light energy can be transformed straight into electrical energy by photovoltaic (PV) cells, while thermal (heat) energy can be used to heat our homes and even cook our food.

How much is left? We won't run out of solar energy, but we need to improve how we collect and store it, especially in the UK, where we don't get consistently strong sun. However solar energy can still be collected on cloudy days.

Is it clean? Yes, the only emissions are produced in building and maintaining the solar panels, as there are with the construction and maintenance of turbines and power stations.

Quick Fact: Solar energy could provide more than enough energy to meet the world's needs several times over, if we can find better ways of capturing and storing it.

BIOMASS

Biomass

What is it used for? Heating, electricity and transport.

Is it renewable? Yes.

How do we collect it? Biomass is organic material that absorbs carbon from the atmosphere. It takes many forms, including wood or special crops. It can be burned in power stations to generate electricity, in boilers to generate heat for homes or turned into liquids to fuel vehicles.

How much is left? Biomass is an abundant resource that humans have been using for hundreds of years. It is a renewable source of energy as long as we ensure our sources of biomass are regrown at the same rate they are being used.

Is it clean? It produces carbon emissions, but the carbon footprint of biomass can vary depending on where the biomass comes from and how it is used. In the case of electricity generation, biomass is less carbon intensive than fossil fuels if the wood comes from sustainably managed forests. Land should be sustainably managed, especially for the growth of biomass that will be turned into fuel for transport.

Quick Fact: Burning wood for energy only releases the carbon that the tree removed from the atmosphere when it was growing.

HYDRO

Hydro

What is it used for? Electricity.

Is it renewable? Yes.

How do we collect it? The potential energy of water behind a dam or in a reservoir can be used to generate electricity.

How much is left? Hydro power is a renewable source of energy, so will not run out. The UK is well placed to take advantage of it's water, and has several large hydro plants.

Is it clean? Yes, hydropower is low carbon when up and running. As with all other power plants, carbon dioxide is released when building hydro stations. Dams can affect local wildlife and local communities by changing the natural habitat and availability of water - but these effects are carefully assessed and monitored before and after construction to ensure they are acceptable.

Quick Fact: Hydro power stations can run for 100 years.

GEOTHERMAL

Geothermal

What is it used for? Heating, cooking and electricity.

Is it renewable? Yes.

How do we collect it? Geothermal energy can be found near the surface of the earth, for example geysers and volcanoes, or deeper underground where we can collect it using drilling techniques.

How much is left? Renewable energy so in theory will not run out as long as Earth's core remains hot!

Is it clean? Yes, once it's up and running. Like all other power plants, the construction and maintenance of geothermal power stations emit some carbon.

Quick Fact: The centre of the earth is extremely hot, could be as hot as 6000 degrees Celsius!

TIDAL

Tidal

What is it used for? Electricity.

Is it renewable? Yes.

How do we collect it? The speed and force of the current works with the constant push and pull of the water to turn an underwater turbine, which generates electricity. Tidal turbines can be planted on the seabed, or built into the walls of a tidal lagoon.

How much is left? Tidal energy is renewable, so will not run out. It's highly predictable and reliable, as it depends on the constant gravitational forces of the moon, but it has periods of high and low generation - at high and low tides.

Is it clean? Tidal energy is clean, and to make sure there is no negative impact on the environment, assessments are carried out on the sea bed before machines are installed.

Quick Fact: Estimated that UK could source 50% of Europe and 10-15% of global tidal energy resource once the technology is more widespread.

WAVE

Wave

What is it used for? Electricity.

Is it renewable? Yes.

How do we collect it? Harnessed from the motion of the high pressure waves being pumped from a wave machine that is secured to the sea bed, down a pipeline to the shore, where it turns a turbine and drives a generator to produce electricity.

How much is left? Wave energy will not run out, as water is a renewable source of energy.

Is it clean? Yes, wave energy is clean, and like tidal energy, assessments are made before projects go ahead to ensure any impact on the underwater environment is acceptable.

Quick Fact: It has been suggested that wave power could be successful in the UK if the technology is developed more in order to make full use of this untapped resource. Scotland alone could provide 10% of Europe's wave energy resources.

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Have you ever thought about where the energy you use on a daily basis - the energy to charge your phone, turn the heating on and get to school - comes from? Read on to find out how we collect primary energy from all around us.

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Energy resources - Energy sources - Edexcel - GCSE Physics (Single Science) Revision - Edexcel - BBC Bitesize

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Learn about and revise the different needs for energy and where it comes from with GCSE Bitesize Physics.

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What are the different types of renewable energy?

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What are the different types of renewable energy?

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With the UK and US aiming to reach net zero by 2050, using electricity that comes from renewable sources is essential to help reduce our carbon emissions.

Each type of renewable energy contributes different amounts to our electricity mix, alongside non-renewable energy types such as fossil fuels or nuclear energy.

Find out about the different types of renewable energy sources that we currently use for electricity and how they'll be used in the future to help further tackle climate change.

What is renewable energy?

Burning fossil fuels to create electricity has long been a major contributor in the emission of greenhouse gases into our atmosphere, so these renewable sources are considered vital in the race to tackle climate change.

The most common renewable energy sources

Wind

Wind power is the largest producer of renewable electricity in both the UK and the US. Onshore and offshore wind farms generate electricity by spinning the blades of wind turbine . The turbines convert the kinetic energy of the spinning blades into electric energy by turning a drive shaft and gear box, which is connected to a generator. Electricity is then converted into higher voltages and fed into the national grid. s

Solar

Sunlight is one of the planet's most freely available energy resources, which you'd assume would make it the number one source of renewable energy. But of course, the amount of sunlight we get can vary greatly depending on location, season and time of day.

Solar power generates electricity by capturing sunlight on solar panels in a joint chemical and physical reaction, known as the 'photovoltaic effect' (or PV).

Hydroelectric

Hydro power is created using the movement of flowing or falling water.Hydroelectric power plants are found at dams and generate electricity through underwater turbines that turn a generator. Hydro power also encompasses wave and tidal power, which rely on ocean forces to generate electricity at the mouths of large bodies of water, using similar technology.

Bioenergy

Electricity can be generated when . These fuels are known as biomass and include anything from plants to timber to food waste. Carbon dioxide (COorganic matter is burned as a fuel source ₂) is emitted when bioenergy is made, but these fuel sources are considered renewable because they can be regrown and absorb as much carbon as they emit across their lifespans.

What are non-renewable energy sources?

A disadvantage of non-renewable energy sources is thatthey often take hundreds of thousands of years to form, and have to be extracted from the earth and burned in order to create the energy that generates electricity. They also emit harmful greenhouse gases like CO ₂ when they're burned.

What are the benefits of renewable energy?

Perhaps most importantly, renewables produce little or no harmful emissions when used, so the clean energy they provide will play a crucial role in preventing further global warming. It's why so many of our net zero goals in the future hinge on increasing their use today.

Is renewable energy the same as clean or green energy?

The terms ' green energy ', 'clean energy' and 'renewable energy' are often used interchangeably, but there is a key difference between them.

Clean energy produces electricity without emissions. However, its manufacture or maintenance can sometimes have a 'carbon cost'. For example, natural environments have to be cleared to create hydroelectric plants with a dam, and the work to construct them often creates carbon emissions.

Green energy comes from totally natural sources, which have low or no environmental impact in their creation or use.

They can both be renewable , which essentially means that they come from a source that can't be depleted.

So, while most green energy sources are renewable, not all renewable energy sources are considered green.

Renewable energy in the modern era

By 2020 - Britain's greenest year on record - renewables contributed a whopping 43.1% of the electricity mix, more than natural gas (34.5%) and coal (1.8%). Combined with low-carbon nuclear energy's 16% contribution, a milestone was reached with the nation being largely powered by clean energy for a year.

Last updated: 10 May 2022
The information in this article is intended as a factual explainer and does not necessarily reflect National Grid's strategic direction or current business activities.

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What are the different types of renewable energy?

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Using electricity that comes from renewable sources is essential to help reduce our carbon emissions. Find out about the different types of renewable energy that we currently use how they'll be used in the future to help further tackle climate change.

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WebTrak is a community-facing platform for reviewing airport operations (flight tracks) and noise. Investigate and review real-time and historical airport noise, flights and weather.

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has sufficient energy to affect the atoms in living cells and thereby damage their genetic material (DNA). Fortunately, the cells in our bodies are extremely efficient at repairing this damage. However, if the damage is not repaired correctly, a cell may die or eventually become cancerous. Related information in Spanish (Información relacionada en español).

Exposure to very high levels of radiation, such as being close to an atomic blast, can cause acute health effects such as skin burns and acute radiation syndrome ("radiation sickness"). It can also result in long-term health effects such as cancer and cardiovascular disease. Exposure to low levels of radiation encountered in the environment does not cause immediate health effects, but is a minor contributor to our overall cancer risk.
Visit the U.S. Centers for Disease Control and Prevention (CDC) for more information about possible health effects of radiation exposure and contamination.
Acute Radiation Syndrome from Large Exposures

A very high level of radiation exposure delivered over a short period of time can cause symptoms such as nausea and vomiting within hours and can sometimes result in death over the following days or weeks. This is known as acute radiation syndrome, commonly known as "radiation sickness."

It takes a very high radiation exposure to cause acute radiation syndrome-more than 0.75 (75 in a short time span (minutes to hours). This level of radiation would be like getting the radiation from 18,000 chest x-rays distributed over your entire body in this short period. Acute radiation syndrome is rare, and comes from extreme events like a nuclear explosion or accidental handling or rupture of a highly radioactive source.
View CDC Fact Sheet: Acute Radiation Syndrome (ARS). Learn about protecting yourself from radiation. Learn about radiation sources and doses.
Radiation Exposure and Cancer Risk

Exposure to low-levels of radiation does not cause immediate health effects, but can cause a small increase in the of cancer over a lifetime. There are studies that keep track of groups of people who have been exposed to radiation, including atomic bomb survivors and radiation industry workers. These studies show that radiation exposure increases the chance of getting cancer, and the risk increases as the dose increases: the higher the dose, the greater the risk. Conversely, cancer risk from radiation exposure declines as the dose falls: the lower the dose, the lower the risk.

Radiation doses are commonly expressed in millisieverts (international units) or (U.S. units). A dose can be determined from a one-time radiation exposure, or from accumulated exposures over time. About 99 percent of individuals would not get cancer as a result of a one-time uniform whole-body exposure of 100 millisieverts (10 rem) or lower. ¹ At this dose, it would be extremely difficult to identify an excess in cancers caused by radiation when about 40 percent of men and women in the U.S. will be diagnosed with cancer at some point during their lifetime.

Risks that are low for an individual could still result in unacceptable numbers of additional cancers in a large population over time. For example, in a population of one million people, an average one-percent increase in lifetime cancer risk for individuals could result in 10,000 additional cancers. The EPA sets regulatory limits and recommends emergency response guidelines well below 100 millisieverts (10 rem) to protect the U.S. population, including sensitive groups such as children, from increased cancer risks from accumulated radiation dose over a lifetime.

Calculate your radiation dose.

Learn about radiation sources and doses.

Learn more about cancer risk in the U.S. at the National Cancer Institute.

Learn more about how EPA estimates cancer risk in, EPA Radiogenic Cancer Risk Models and Projections for the U.S. Population, also known as the Blue Book.

Limiting Cancer Risk from Radiation in the Environment

EPA bases its regulatory limits and nonregulatory guidelines for public exposure to low level ionizing radiation on the linear no-threshold (LNT) model. The LNT model assumes that the risk of cancer due to a low-dose exposure is proportional to dose, with no threshold. In other words, cutting the dose in half cuts the risk in half.

The use of the LNT model for radiation protection purposes has been repeatedly recommended by authoritative scientific advisory bodies, including the National Academy of Sciences and the National Council on Radiation Protection and Measurements . There is evidence to support LNT from laboratory data and from studies of cancer in people exposed to radiation. 2,3,4,5

Exposure Pathways

Understanding the type of radiation received, the way a person is exposed (external vs. internal), and for how long a person is exposed are all important in estimating health effects.

The risk from exposure to a particular depends on:

The energy of the radiation it emits.

The type of radiation (alpha, beta, gamma, x-rays).

Its activity (how often it emits radiation).

Whether exposure is external or internal:

External exposure is when the radioactive source is outside of your body. X-rays and gamma rays can pass through your body, depositing energy as they go.

Internal exposure is when radioactive material gets inside the body by eating, drinking, breathing or injection (from certain medical procedures). Radionuclides may pose a serious health threat if significant quantities are inhaled or ingested.

The rate at which the body metabolizes and eliminates the radionuclide following ingestion or inhalation.

Where the radionuclide concentrates in the body and how long it stays there.

Learn more about alpha particles, beta particles, gamma rays and x-rays.
Sensitive Populations

Children and fetuses are especially sensitive to radiation exposure. The cells in children and fetuses divide rapidly, providing more opportunity for radiation to disrupt the process and cause cell damage. EPA considers differences in sensitivity due to age and sex when revising radiation protection standards.

1 National Research Council, 2006. Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2. Washington, DC: The National Academies Press (p. 7).
2 Brenner, David J. et al., 2003 "Cancer risks attributable to low doses of ionizing radiation: assessing what we really know." Proceedings of the National Academy of Sciences 100, no. 24, (pp. 13761-13766).
3 National Council on Radiation Protection and Measurements, 2018. Implications of Recent Epidemiologic Studies for the Linear Nonthreshold Model and Radiation Protection, NCRP Commentary 27. Bethesda, Maryland: National Council on Radiation Protection and Measurements.
4 Shore, R.E. et al., 2018. "Implications of recent epidemiologic studies for the linear nonthreshold model and radiation protection." Journal of Radiological Protection, no 38,(pp. 1217-1233)
⁵ U.S. Environmental Protection Agency, 2011. "EPA Radiogenic Cancer Risk Models and Projections for the U.S. Population." EPA Report 402-R-11-001.

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has sufficient energy to affect the atoms in living cells and thereby damage their genetic material (DNA). Fortunately, the cells in our bodies are extremely efficient at repairing this damage. However, if the damage is not repaired correctly, a cell may die or eventually become cancerous. Related information in Spanish (Información relacionada en español).

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Road transport is the most significant contributor to environmental noise pollution in the EU. EU policies are put in place to reduce exposure to and the harmful effects of noise pollution.

Living close to a road, railway or airport can be more than just a nuisance - at least one in five people in the EU are exposed to long-term noise levels considered harmful to their health. Health issues related to these exposures include annoyance, sleep disturbance, and cardiovascular and metabolic issues. It can also affect children's ability to learn.

In many cities, more than half of the population is exposed to road noise levels above the World Health Organisation guidelines for the day-evening-night period. Many people are also affected by noise from aircraft and railways. Although noise from railways and aircraft has a much lower impact in terms of the overall population, both are significant sources of local noise pollution. As in the case of air pollution and climate change impacts, some communities and social groups might be more likely to be exposed to and affected by noise pollution. The impacts of railway noise could potentially increase in the coming years due to more and faster trains.

Given noise's negative impacts on a large portion of Europe's population, environmental noise has become a significant concern for citizens and policymakers. Noise pollution also affects wildlife. It can cause various physical and behavioural issues in animals and increase their stress.

Reducing noise is a key objective under the EU's Zero Pollution Action Plan and the Environmental Noise Directive (END).

Long-term exposure to noise harms physical and mental health. In Europe, at least one in five is exposed to chronic levels that can cause adverse health effects. Our estimates from the European Union show that:

About 95 million people are exposed to harmful levels of road traffic noise.

At least 20% of the urban population is exposed to levels considered harmful to health. In many cities, this percentage can reach 50% of the urban population.

It is estimated that at least 18 million people are highly annoyed and 5 million are highly sleep disturbed by long-term exposure to noise from transport in the EU.

In addition, it is estimated that long-term exposure to transport noise causes about 11,000 premature deaths and 40,000 new cases of ischaemic heart disease.

The Environmental Noise Directive provides the primary legislative framework for achieving noise reduction in Europe. The directive offers a common approach to avoiding and preventing exposure to environmental noise by reporting noise maps and action plans. This helps to reduce the harmful effects of noise and preserve quiet areas.
The Environmental Noise Directive aims to:

Produce strategic noise maps for all major roads, railways, airports and urban areas using harmonised noise indicators.

Determine how many people are exposed to specific transport noise sources inside and outside urban areas and at large industrial installations inside urban areas.

Adopt action plans based on noise mapping results to help prevent and reduce environmental noise, especially in areas where exposure levels affect human health.

Select and preserve 'quiet' areas to protect the European soundscape.

Apart from this directive, there are other legislative measures that aim to address or control sources of noise by imposing noise limits on certain vehicles or equipment and by restricting their operation.

The levels of noise generated by transport sources are generally too low to cause biological damage to the ear; however, it is well established that long-term exposure to noise above certain levels can lead to non-auditory health effects such as annoyance, sleep disturbance, negative effects on the cardiovascular and metabolic systems, and cognitive impairment in children.

Reducing the negative impacts of exposure to environmental noise is a key objective under the EU's zero pollution action plan, which aims to reduce the number of people chronically disturbed by noise from transport by 30% by 2030 (compared with 2017).

Within the European Union, the Environmental Noise Directive (END; 2002/49/EC) defines quiet areas outside cities as "those areas delimited by national authorities that are undisturbed by noise from traffic, industry or recreational activities".

Our report 'Quiet areas in Europe: the environment unaffected by noise pollution,' provides a first mapping assessment of potential quiet areas in Europe's rural regions. Approximately 18% of Europe's area can be considered quiet, but about a third is potentially affected by noise pollution.

Several cities and regions have put in place so-called quiet areas in parks and other green spaces where people can go to escape the city noise. These areas can bring significant environmental and health benefits. Still, EEA research found that these sites were often not available or difficult to access, especially in noisier city centres.

Noise negatively impacts wildlife, both on land and in the sea. Noise pollution can cause various physical and behavioural issues in animals and increase their stress.

For example, road traffic noise can make it difficult for frogs and songbirds to communicate with each other, especially during mating season. This can reduce their ability to reproduce or force them to flee their habitats.

Underwater noise from shipping, energy production, construction and other activities is also a concern. Research shows that hearing damage in whales can harm their ability to communicate with each other and find food.

Road traffic remains the top source of noise pollution in Europe, the new EEA report ' Noise in Europe - 2020 ' says, with noise levels projected to rise in both urban and rural areas over the next decade due to urban growth and increased demand for mobility. Rail, aircraft and industry round up the other top sources of environmental noise pollution.

With the publication in 2018 of the WHO Environmental noise guidelines for the European Region, there is greater insight into the negative effects of noise on health and a growing awareness of the need to reduce noise pollution.

The guidelines presented recommendations on reducing noise levels for road, railway, aircraft, wind turbine and leisure noise sources and showed that low levels of noise, currently not captured in the EU Environmental Noise Directive, are likely to cause health problems.

The introduction of the guidelines triggered actions at local, national and supra-national level. A brief has been prepared jointly by the WHO Regional Office for Europe and the European Environment Agency to evaluate the uptake and impact of the guidelines by drawing on the experiences from countries.

Long-term exposure to environmental noise from road, rail and aircraft sources is a serious risk to health, impacting the lives of many people in Europe.

The European Environment and Health Atlas in Europe offers an overview of quiet areas, urban noise levels and noise around schools and hospitals.

More information

Other topics you might be interested in:

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Road transport is the most significant contributor to environmental noise pollution in the EU. EU policies are put in place to reduce exposure to and the harmful effects of noise pollution.

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Dealing with land contamination to help make the environment clean and safe.

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The World Water Quality Alliance (WWQA) - Uniting society to protect the future
Water is life. It is that simple.
We need water to survive, just as much as we need air, sunlight and food. Nothing can live without access to this vital element. Ensuring the quality of water is one of the great global challenges of the 21st Century. In order to do so, scientists, researchers, politicians, water professionals, artists, and citizens of all genders, ethnic groups, ages and social sectors, but especially the younger generations, will need to work together. Reliable, readily accessible data will be essential, as will translating the knowledge contained in it into realistic, tangible actions, if we are to build and guarantee a future for all. That is the purpose of the World Water Quality Alliance (WWQA), its members, and its governing bodies. Join us.
The WWQA: The Beginnings
Water quality is influenced by natural phenomena. However, most oceans, lakes and rivers are affected sometimes to a dramatic extent by human activity. We urgently need to understand how this affects the quality of water, and how we can address the challenges this creates.

This basic fact of life was recognized by the United Nations Environment Assembly (UNEA) at its third session in December 2017 when it adopted Resolution 3/10 "Addressing water pollution to protect and restore water-related ecosystems" ( UNEP/EA.3/Res.10). This requested the Executive Director of the UN Environment Programme (UNEP) to develop a World Water Quality Assessment for the consideration of UNEA. To begin the development of the Assessment, UNEP, with support from the World Meteorological Organization (WMO), organized a workshop in November 2018. During the workshop, UNEP convened about 50 organizations (UN, research, civil society, private sector) that had expressed an interest in engaging with the Assessment and in working with UNEP in co-designing agendas and actions on emerging issues of concern affecting water quality. This process marked the founding of the World Water Quality Alliance (WWQA) as an open community of practice with several workstreams currently under implementation.

The WWQA represents a voluntary, flexible and global, multi-stakeholder network that advocates the central role of freshwater quality in achieving prosperity and sustainability. It explores, monitors, analyses and communicates water-quality risks at global, regional, national and local levels with the aim of identifying solutions for the maintenance and restoration of the health and well-being of both ecosystems and humans. The WWQA serves countries throughout the lifetime of the 2030 Agenda for Sustainable Development and beyond. It provides a participatory platform for water-quality assessment and the co-design of tailored and demand-driven services at all levels with a special emphasis on the involvement of local communities and the younger generations whose future is at risk

The WWQA focuses on improving the quality of water around the world by working as a genuine partnership. Everyone, no matter their qualifications or expertise, has an important role to play. The efforts of the WWQA are currently divided into 16 active workstreams to ensure the involvement of society as a whole.
Click here for more information about the World Water Quality Alliance

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world water quality alliance (wwqa) – a partnership effort

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World Water Quality Alliance (WWQA) - a partnership effort

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The World Water Quality Alliance (WWQA) - Uniting society to protect the future Water is life. It is that simple. We need water to survive, just as much as we need air, sunlight and food. Nothing can live without access to this vital element.

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The excessive raising or lowering of water temperature above or below normal seasonal ranges in streams, lakes, or estuaries or oceans as the result of discharge of hot or cold effluents into such water.

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Photochemical smog is a type of smog produced when ultraviolet light from the sun reacts with nitrogen oxides in the atmosphere. It is visible as a brown haze, and is most prominent during the morning and afternoon, especially in densely populated, warm cities. Cities that experience this smog daily include Los Angeles, Sydney, Mexico City, Beijing, and many more.

Photochemical smog forms from a complex process, however the source of it is quite apparent. The largest contributor is automobiles, while coal-fired power plants and some other power plants also produce the necessary pollutants to facilitate its production. Due to its abundance in areas of warmer temperatures, photochemical smog is most common in the summer.

It forms in the morning when a tremendous number people are driving their vehicles to work. Nitrogen oxides produced in the car engine are introduced into the atmosphere, which may combine with water to form nitric acid or react with sunlight to produce singular oxygen atoms, which then combine with molecular oxygen to produce ozone. The nitric acid may precipitate to the Earth resulting in acid rain, or remain in the smog. Due to the direct production of it by vehicles, the smog forms over cities where many people may encounter its adverse health effects.

Hotter days mean more photochemical smog, especially in the densely populated cities such as those mentioned above. As more and more urban populations arise around the globe, this problem is only expected to increase.

Composition

Nitric oxide (NO) and nitrogen dioxide (NO ₂) are emitted from the combustion of fossil fuels, along with being naturally emitted from things such as volcanos and forest fires (it is the immense concentration of these pollutants within cities that is of the most concern however, as natural emissions tend to spread out over larger areas). When exposed to ultraviolet radiation, NO ₂ goes through a complex series of reactions with hydrocarbons to produce the components of photochemical smog-a mixture of , nitric acid, aldehydes, peroxyacyl nitrates ( PANs) and other secondary pollutants.

NO ₂, ozone and PANs are called photochemical oxidants because they can react and oxidize certain compounds in the atmosphere or within a person's lungs that are not normally oxidized. Even small traces of these chemicals can affect the respiratory tract of humans and animals, and damage crops and trees.

Photochemical smog has many adverse effects. When combined with hydrocarbons, the chemicals contained within it form molecules that cause eye irritation. Radicals in the air interfere with the nitrogen cycle by preventing the destruction of ground level ozone. Other effects include reduced visibility and respiratory ailments.

Ground level ozone is also produced which has various effects on the human body. For more information, visit the ozone page.

For Further Reading

References

1. Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/d/d1/Shanghaiairpollutionsunset.jpg

2. B. Everett, G. Boyle, S. Peake and J. Ramage, "," in "Penalties: Assessing the Environmental and Health Impacts of Energy Use," in Energy Systems and Sustainability, 2nd ed., Oxford, UK: Oxford, 2013, ch.13, pp.543

3. R. A. Hinrichs and M. Kleinbach, "Nitrogen oxides, photochemical smog and ozone," in Energy: Its Use and the Environment, 5th ed. Toronto, Ont. Canada: Brooks/Cole, 2013, ch.8, sec.C, pp.250-252

4. G. Tyler Miller, Jr. and D. Hackett, "Photochemical and Industrial Smog," in Living in the Environment, 2nd ed. USA: Nelson , 2011, ch.20, sec.3, pp.465-471

5. Adapted from Living In The Environment. See Reference 4.

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Photochemical smog is a type of smog produced when ultraviolet light from the sun reacts with nitrogen oxides in the atmosphere. It is visible as a brown haze, and is most prominent during the morning and afternoon, especially in densely populated, warm cities.

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Department for Environment, Food and Rural Affairs (Defra) webmasterdefra.gsi.gov.uk

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national oceanic and atmospheric administration

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Oil spills are harmful to marine mammals and birds as well as fish and shellfish

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Pollution is the introduction of harmful materials into the environment. These harmful materials are called pollutants.

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Methods and Mechanisms for Genetic Manipulation of Plants, Animals, and Microorganisms

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Methods and Mechanisms for Genetic Manipulation of Plants, Animals, and Microorganisms

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Methods and Mechanisms for Genetic Manipulation of Plants, Animals, and Microorganisms

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This chapter provides a brief description of genetic modification methods used to develop new plant, animal, and microbial strains for use as human food. The next chapter (Chapter 3) presents a detailed analysis of the likelihood for these methods to result in unintentional compositional changes.

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Pesticides known as Plant protection products are used to control pests, weeds and diseases. There are many different types of plant protection product, common examples include: insecticides, fungicides, herbicides, molluscicides, and plant growth regulators

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Aquaculture is the farming of fish, shrimps, seaweed and molluscs. Learn more about this fast-growing food production system here.

Why we work on Aquaculture

Aquaculture has been practiced for thousands of years and involves many species and farming methods. It is one of the fastest growing food-producing sectors in the world. If this growth continues, aquaculture will become as important as other food production like poultry, pork and even fishing!

When done responsibly, the impacts of aquaculture can be minimal, but when farms are poorly managed, aquaculture can have substantial impacts on the environment, climate and society. For example:

Chemicals used can sometimes pollute the water.

If farmed fish escape, they can negatively impact wild populations.

Disease can spread from farmed to wild fish.

Feed production can require wild-caught species that are an important food source to both marine predators and people, and soy can be linked to deforestation.

Feed production can be linked to illegal, unreported and unregulated (IUU) fishing, and human welfare issues.

Certain kinds of aquaculture can even be regenerative for the ocean. Seaweed and shellfish aquaculture can improve ocean health and biodiversity by filtering water, providing habitat, and reducing acidity.

Creating a sustainable supply of seafood from aquaculture will only be possible if the social and environmental impacts from aquaculture are minimised. WWF is working to address these issues, to ensure seafood produced via aquaculture aligns with a future where people and nature can thrive.

How we work on Aquaculture - Aquafeed

Some aquaculture species (fish and crustaceans) need to be fed during production, with a nutritionally suitable feed (aquafeed).

In the past a large proportion of this feed was made up of fish meal and fish oil, sourced from wild caught fisheries, which put significant pressure on fish stocks and marine ecosystems.

Although aquafeed, particularly for salmon and trout, now contains much less fish meal and fish oil, having been replaced by more vegetable ingredients such as soy protein and rapeseed oil, these aquafeed ingredients still carry risks associated with deforestation, freshwater use, and greenhouse gas emissions.

Learn more about our work on Aquafeed.

How we work on Aquaculture - Regenerative seaweed farming

Seaweeds are marine plants (algae) and are a natural part of marine ecosystems. For example, kelp forests support sea otters, seals, and seabirds. In many parts of Southeast Asia seaweed is farmed for use in foods like sushi. Here in the UK, we have a long tradition of wild harvesting of seaweed, which has gone into foods like laverbread in Wales.

Farming seaweed can be a regenerative food production method and a nature-based solution. Growing seaweed does not require land, feed, freshwater, fertiliser, or pesticides. This makes it a very low impact production method. Seaweed also has the added advantage of absorbing excess nutrients from the sea, such as nitrogen and phosphorus that runs from land into river and then into ocean. Seaweed farms can also temporarily remove carbon from the ocean, and displace carbon intensive products, helping us to combat climate change.

Seaweed and other aquatic plants have great potential to provide food for people, feed (e.g. protein) and nutrients (e.g. DHA, oil) for livestock, farmed fish and crustaceans. Seaweed could also one day be a substitute for synthetic fertilisers .

Around 30 million tonnes of seaweed is already produced globally, but there is potential to grow much more, and UK waters offer perfect conditions. Therefore, WWFs Seaweed Solutions programme is supporting seaweed farming in the UK.

Reducing synthetic fertiliser with seaweed

In 2023, WWF received a grant from round two of Co-op UK and Co-op UK Foundation's £3.5m Carbon Innovation Fund. The funding will allow us to explore if seaweed biostimulant can reduce the quantity of synthetic fertiliser required to grow crops, and bring down the carbon emissions of food production. Using seaweed sourced from UK seas on farms in Norfolk, this exciting project will take us a step closer to a regenerative agriculture where land and sea are connected in one system.

We also recommend:
Seafood top tips: making responsible seafood choices Working on seafood: The Blue Food Learn More About Seafood Illegal, Unreported and Unregulated Fishing

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Learn about the aquaculture food production system

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Aquaculture is the farming of seafood including fish, shrimps, seaweed and molluscs. Learn more about this fast-growing food production system here.

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What is overfishing and why is it a problem?

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What is overfishing and why is it a problem?

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Overfishing is a serious global problem that threatens ocean wildlife and biodiversity. Loss of marine life brings a further threat to the millions of people who rely on seafood for protein and livelihoods.

What is overfishing and why is it a problem?

Overfishing occurs when too many fish in a particular stock are caught and there are not enough adults to breed and sustain a healthy population.

The level of overfishing has been increasing in recent decades and the number of overfished stocks is now three times higher than in 1970. The United Nations Food and Agriculture Organization monitors over 500 fish stocks around the globe. In 2024, it is estimated that over 37% of these fish stocks were overfished.

For communities reliant on fishing, the impact of stock collapses can be devastating. Overfishing is also a concern for the wild marine environment as it is one of the major causes of the loss of ocean biodiversity.

"Tackling overfishing is a 'win-win' for our planet. By conserving our rich marine resources, we also enable more people to have the protein they need to live healthily."

Dr Rohan Currey

MSC Chief Science and Standards Officer

What is driving overfishing?

There are several factors that drive overfishing, these include:

What are the consequences of overfishing?

Almost 38 million people are directly employed in the wild capture seafood sector. Figures from the 2020 UN FAO State of the World Fisheries Report show 10% of the world's population rely, at least partially, on fishing and aquaculture for their livelihoods.

If fish stocks collapse the impact can be immediate, but recovery can take decades. The collapse of Canada's Grand Banks cod fishery in 1992 left over 35,000 fishers and plant workers from more than 400 coastal communities without jobs.

Seafood is also an important source of protein and micronutrients. More than 3 billion people are dependent on the ocean for protein, with fish representing at least 20% of their daily animal protein intake.

The impact of overfishing on biodiversity

Overfishing can affect biodiversity, habitats and ecosystems that make vital contributions to the climate, clean air, water and food.

Biodiversity impacts can take place not only through overfishing of fish stocks targeted for food, but also through overfishing of species caught unintentionally. This can include endangered species such as some sharks, rays, and turtles. Removing sharks, for example, can have knock-on effects on their prey and species lower down the food chain, and negatively impact biodiversity.

What can be done about overfishing?

Stopping overfishing doesn't mean stopping fishing altogether. Fisheries that are sustainably managed are better for the environment and more productive in the long-term.

If all fisheries were sustainably managed there would be an estimated 16 million more tonnes of fish a year, which would yield enough protein for 72 million more people.

As the world grapples with how to feed its growing population, sustainably produced foods from the sea will have an increasingly important role to play.

Despite the headline statistics on overfishing, there has been steady progress on the availability of sustainable seafood for consumers. 2019 figures in the FAO Blue Transformation report found that 82% of fish landings by volume come from sustainably managed stocks, an increase of nearly 4%. This means consumers are increasingly empowered to make sustainable choices, especially for popular species like tuna, pollock and anchoveta.

What is the MSC doing about overfishing?

The MSC was founded in response to overfishing and our Fisheries Standard can play a major role in its prevention.

Almost a fifth of the globe's world marine catch is certified or in assessment to the Standard. It is a globally recognised benchmark for seafood sustainability and reflects the most up-to-date understanding of internationally accepted fisheries science and management.

The MSC Fisheries Standard is a set of requirements that ensure fisheries aiming to be certified as environmentally sustainable only target stocks that are abundant and able to replenish themselves, and that fisheries minimise their impact on the wider marine ecosystem. The Standard also requires that fishing is well-managed, and fishers abide by the relevant local, national and international laws.

Assessments are carried out independently and audits are made every year to make sure requirements are being met.

Recent MSC research found that fish stocks targeted by fisheries certified to the MSC Standard perform better on key sustainability benchmarks than those targeted by non-certified fisheries. These stocks are healthier, more abundant, and much less prone to overfishing.

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Overfishing is a global problem that threatens ocean life and brings a further threat to the millions who rely on seafood for protein and livelihoods.

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Deforestation is the purposeful clearing of forested land. Throughout history and into modern times, forests have been razed to make space for agriculture and animal grazing, and to obtain wood for fuel, manufacturing, and construction.

Deforestation has greatly altered landscapes around the world. About 2,000 years ago, 80 percent of Western Europe was forested; today the figure is 34 percent. In North America, about half of the forests in the eastern part of the continent were cut down from the 1600s to the 1870s for timber and agriculture. China has lost great expanses of its forests over the past 4,000 years and now just over 20 percent of it is forested. Much of Earth's farmland was once forests.

Today, the greatest amount of deforestation is occurring in tropical rainforests, aided by extensive road construction into regions that were once almost inaccessible. Building or upgrading roads into forests makes them more accessible for exploitation. Slash-and-burn agriculture is a big contributor to deforestation in the tropics. With this agricultural method, farmers burn large swaths of forest, allowing the ash to fertilize the land for crops. The land is only fertile for a few years, however, after which the farmers move on to repeat the process elsewhere. Tropical forests are also cleared to make way for logging, cattle ranching, and oil palm and rubber tree plantations.

Deforestation can result in more carbon dioxide being released into the atmosphere. That is because trees take in carbon dioxide from the air for photosynthesis, and carbon is locked chemically in their wood. When trees are burned, this carbon returns to the atmosphere as carbon dioxide. With fewer trees around to take in the carbon dioxide, this greenhouse gas accumulates in the atmosphere and accelerates global warming.

Deforestation also threatens the world's biodiversity. Tropical forests are home to great numbers of animal and plant species. When forests are logged or burned, it can drive many of those species into extinction. Some scientists say we are already in the midst of a mass-extinction episode.

More immediately, the loss of trees from a forest can leave soil more prone to erosion. This causes the remaining plants to become more vulnerable to fire as the forest shifts from being a closed, moist environment to an open, dry one.

While deforestation can be permanent, this is not always the case. In North America, for example, forests in many areas are returning thanks to conservation efforts.

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Deforestation is the intentional clearing of forested land.

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Term

Forests have been exploited over the centuries as a source of wood and for obtaining land for agricultural use. The mismanagement of forest lands and forest resources has led to a situation where the forest is now in rapid retreat. The main aspects of the situation are: serious shortages in the supply of industrial wood; the catastrophic erosion and floods accompanying the stripping of forests from mountainous land; the acute shortages of fuel wood in much of the developing world; the spread of desert conditions at an alarming rate in the arid and semi-arid regions of the world; and the many environmental effects of the destruction of tropical rainforests. (Source: WPR)

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Forests have been exploited over the centuries as a source of wood and for obtaining land for agricultural use. The mismanagement of forest lands and forest resources has led to a situation where the forest is now in rapid retreat.

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Why Forests Matter | Forest Stewardship Council

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Why Forests Matter | Forest Stewardship Council

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Forests regulate our climate, clean the air we breathe, and filter the water we drink. They also provide habitat for more than two-thirds of terrestrial wildlife and plants.

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Kalundborg’s Eco-Industrial Park Transformed Waste into Savings

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Kalundborg’s Eco-Industrial Park Transformed Waste into Savings

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Rio Bravo Conservation & Management Area

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Rio Bravo Conservation & Management Area

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Generally speaking the entire area forms part of the Yucatan Platform and is underlain by massive beds of limestone. Faulting on a NE-SW alignment has created a series of blocks that are slipping downwards to the east, resulting in a series of escarpments across the landscape - Lalucha, Rio Bravo, Booth's River and New River within the RBCMA with the sequence continuing eastwards to the outer cayes.

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Development Trusts Association Scotland

Large and small, rural and urban, mainland and island-based, communities all over Scotland are setting up development trusts to help their neighbourhoods flourish through community-led activity, partnership working and enterprise.

As a membership organisation, the Development Trusts Association Scotland (DTAS) uses its expertise to inform, support and represent this network of development trusts, facilitating the sharing of knowledge and expertise and encouraging mutualism and co-operation.
Read Our Lastest Blogs from the DTA Scotland Team.

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Development Trusts Association Scotland |

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Large and small, rural and urban, mainland and island-based, communities all over Scotland are setting up development trusts to help their neighbourhoods flourish through community-led activity, partnership working and enterprise. As a membership organisation, the Development Trusts Association Scotland (DTAS) uses its expertise to inform, support and represent this network of development trusts, facilitating the sharing of knowledge and expertise and encouraging mutualism and co-operation.

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Soil erosion: An agricultural production challenge

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Soil erosion: An agricultural production challenge

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Soil erosion is a gradual process that occurs when the impact of water or wind detaches and removes soil particles, causing the soil to deteriorate. Soil deterioration and low water quality due to erosion and surface runoff have become severe problems worldwide. The problem may become so severe that the land can no longer be cultivated and must be abandoned. Many agricultural civilizations have declined due to land and natural resource mismanagement, and the history of such civilizations is a good reminder to protect our natural resources.

Erosion is a serious problem for productive agricultural land and for water quality concerns. Controlling the sediment must be an integral part of any soil management system to improve water and soil quality. Eroded topsoil can be transported by wind or water into streams and other waterways. Sediment is a product of land erosion and derives largely from sheet and rill erosion from upland areas, and to a lesser degree, from cyclic erosion activity in gullies and drainageways.

The impact of soil erosion on water quality becomes significant, particularly as soil surface runoff. Sediment production and soil erosion are closely related. Therefore, the most effective way to minimize sediment production is the stabilization of the sediment source by controlling erosion. Several conservation practices can be used to control erosion but first you need to understand the factors affecting soil erosion. Soil erosion is the detachment and movement of soil particles from the point of origination through the action of water or wind. Thus, minimizing the impact of water or wind forces is the main objective for erosion control. Water erosion is the most pertinent erosion problem in Iowa.

Soil erosion by water occurs when bare-sloped soil surface is exposed to rainfall, and the rainfall intensity exceeds the rate of soil intake, or infiltration rate, leading to soil-surface runoff. Soil erosion can occur in two stages: 1) detachment of soil particles by raindrop impact, splash, or flowing water; and 2) transport of detached particles by splash or flowing water. Therefore, soil erosion is a physical process requiring energy, and its control requires certain measures to dissipate this energy.

The hydrologic processes of rainfall and runoff play an essential role in water erosion. The amount and rate of surface runoff can affect erosion and sediment transport. Thus, soil conservation practices are important in reducing soil erosion. Improving the soil infiltration rate, resulting in less surface runoff, can lead to reduction of soil erosion. Agronomic, cultural, or structural practices are available for controlling soil erosion. Structural practices involve physical changes in the shape and topography of the land. All these practices are not mutually exclusive. Some situations may require both management and structural changes, where the topography is highly complex. In other situations, erosion control can be achieved by implementing a single practice, where the erosion is minimum, such as the establishment of grassed waterways.

Sheet erosion (water) is almost invisible. Lighter colored soils are a sign that over the years erosion has taken its toll.

Wind erosion is highly visible. Although it is a problem, water erosion is generally much more severe.

Rill erosion occurs during heavy rains, when small rills form over an entire hillside, making farming difficult.

Gully erosion makes gullies, some of them huge, impossible to cross with farm machinery.

Ephemeral erosion occurs in natural depressions. It differs from gully erosion in that the area can be crossed by farm equipment.

The most effective way to control erosion is to maintain a permanent surface cover on the soil surface, such as pasture or meadow. Therefore, areas that are highly susceptible to water or wind erosion need to be considered for soil conservation programs. Soil losses in Iowa due to water erosion and surface runoff can contribute a great deal to surface water quality concerns.

Many studies indicate that soil erosion results in large decreases in soil productivity. In a study conducted at Iowa State University on 40 soil associations, Craft and coworkers ( Proceedings of the National Symposium on Erosion and Soil Productivity, 1984) reported that the impact of soil erosion on soil productivity was largely determined by subsoil properties because they effect root growth, soil water availability, and plow layer fertility. Thus, the loss of the topsoil can have considerable impact on yield, where nutrient availability, root growth environment, and soil water availability are essential for plant development. In soils with unfavorable subsoil conditions, erosion can have a large effect on productivity, if the plow layer soil fertility is not restored.

Plant residue management is another way of controlling soil erosion by intercepting raindrops, thereby reducing surface runoff and protecting soil surface particle detachment by raindrop impact. Crop residue can provide an excellent soil cover after harvest and enhance snow harvesting during the off season, improve soil water intake by preventing soil surface sealing due to raindrop impact, and consequently, reduce surface runoff. Equally important in minimizing soil erosion is the adoption of a cropping system along with conservation tillage practices such as no-till, strip-till, and ridge-till. The degree of effectiveness of different tillage practices depends on the degree of soil manipulation, which effects the residue distribution on the soil surface. Table 1 shows combinations of different cropping systems and the relative scale of erosion hazard associated with each system.
Table 1. Relative erosion hazards of selected cropping systems.
C, corn; Sb, Soybean; O, oats; Ox, oats with green manure crop; M, meadow.

This article originally appeared on pages 141-143 of the IC-484(19) -- July 24, 2000 issue.

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Soil erosion: An agricultural production challenge

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Soil erosion is a gradual process that occurs when the impact of water or wind detaches and removes soil particles, causing the soil to deteriorate. Soil deterioration and low water quality due to erosion and surface runoff have become severe problems worldwide.

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The Universal Soil Loss Equation (USLE) is a powerful tool that is widely used by soil conservationists in the United States and many other countries.

The USLE was developed by W. H. Wischmeier, D. D. Smith, and others with the U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), Soil Conservation Service (SCS), and Purdue University in the late 1950s. Its field use was institutionalized in the form of USDA Agricultural Handbook 282 in 1965, and later updated as USDA Agricultural Handbook 537 in 1978.

The USLEestimates average annual soil loss by sheet and rill ero sion on those portions of landscape profiles where erosion, but not deposition, is occur ring. It does not estimate deposition like that at the toe of concave slopes, and it does not estimate sediment yield at a downstream location. Also, it does not include ephemeral gully erosion.

The USLE is an empirically based equation,derived from a large mass of field data, especially erosion plots and rainfall simulator experiments , and computes sheet and rill erosion as follows: A=RKLSCP where A is computed soil loss, R is the rainfall-runoff erosivity factor, K is a soil erodibility factor, L is the slope length factor, S is the slope steepness factor, C is a cover management factor, and P is a supporting practices factor.

The R-factor is calculated as a product of the kinetic energy of a rainfall times its maximum 30-minute intensity of fall. As durations and intensities of rainstorms vary considerably from year to year, it is essential to consider a sufficiently long time period to obtain a representative R-value.

The K-factor represents the ease with which a soil can be eroded and is influenced by the soil texture, organic matter content, soil structural strength and permeability. K-values therefore need to be determined for individual soil types and can be estimated for known soils using the USDA erodibility nomograph

The L and S factors express the influence of the landscape on soil erosion. The LS combination is the ratio of soil loss from a particular slope to a 'reference slope (22.1 m length and uniform 9% grade).

The C-factor is the ratio of erosion under a specified cover and management to the amount of erosion under a continuous bare fallow. It considers the type and density of vegetative cover on the soil as well as all related management practices, such as time between operations, weed control, tillage, watering, fertilization, crop residues etc. This factor is obviously very complicated and can only be assessed with confidence for research-verified crop/land management combinations.

The P-factor is the ratio of the erosion resulting from the described practice to that which would occur with up-and-down slope cultivation. It recognizes the influence of conservation practices, such as contour planting, strip cropping, terracing and combinations.

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The Universal Soil Loss Equation (USLE) is a powerful tool that is widely used by soil conservationists in the United States and many other countries. The USLE was developed by W. H. Wischmeier, D. D. Smith, and others with the U.S.

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Soil Erodibility in Europe - ESDAC - European Commission

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With the Land Use/Cover Area frame Survey (LUCAS) soil survey in 2009 a pan-European soil dataset is available for the first time, consisting of around 20,000 points across 25 Member States of the European Union. The LUCAS (Land Use/Cover Area frame Survey) is an in-situ assessment, whichmeans that the data is gathered through direct field observations. The aimof the LUCAS survey is to establish a fully harmonised database within the EU on land use/cover and to document changes over time. A soil module was included in the LUCAS dataset for the first time in 2009.

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Nitrogen Cycle: Steps, Process, Significance, Human Influence

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Nitrogen Cycle- Steps and Significance. Its is the movement of nitrogen between the atmosphere, biosphere, and geosphere in different forms.

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What Are Biogeochemical Cycles and Why Are They Important?

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What Are Biogeochemical Cycles and Why Are They Important?

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What Are Biogeochemical Cycles and Why Are They Important?

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Explore how essential elements move between the environment and living things in a delicate balance, and learn how this vital planetary process is being altered.

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Learn about the carbon cycle. Get its definition, see the steps involved, and discover why the carbon cycle is important.

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What is the phosphorus cycle?

Biogeochemical process showing the movement of phosphorus and its different forms in nature with the help of living organisms is called the phosphorus cycle.

Phosphorus Cycle Diagram

What are the main sources of phosphorus in the phosphorus cycle?

Rocks, water, soil, and sediments constitute the primary nonliving sources of phosphorus, whereas plants and animals form the major living sources.

What are the five steps of the phosphorus cycle?
1) Weathering
Over a long period, phosphates found in the sedimentary rocks as PO ₄ ³⁻, are leached out of the disintegrated rocks from its various environmental sources in the form of inorganic phosphate ions. This process called weathering acts as the first key step of the phosphorus cycle.

Other than weathering, volcanic ash, aerosols, and mineral dust also serve as other significant phosphate sources.
2) Mineralization by plants
Plants absorb organic phosphorus present in soil and underground water and convert them to inorganic forms for utilization is called mineralization.

The aquatic plants absorb inorganic phosphorus from lower layers of water bodies due to their low solubility in water.
3) Assimilation by animals
Herbivorous and carnivorous animals, including humans, absorb phosphorus when they consume these plants for their food, a process known as assimilation. Besides, animals obtain phosphorus directly from drinking water.
4) Decomposition by microorganisms
Microorganisms such as bacteria and fungi decompose organic phosphates back into the inorganic form, which is then returned to the soil and water bodies. Phosphorus-containing compounds may also be carried in the surface runoff to rivers, lakes, and oceans to form sediments.
5) Geological uplift by tectonic movements
Over long periods, sedimentary rocks containing phosphorus may be moved from the ocean to the land by a process called geological uplift. The phosphorus thus deposited as sediments are ultimately released back into the environment through the process of weathering, thus completing the cycle.

Why is the phosphorus cycle important?

Acts as an essential component of nucleotides and nucleic acids such as DNA and RNA

Forms an essential component of our bone and the enamel of mammalian teeth

Constitutes an essential component of the phospholipids present in the biological membranes such as cell membrane

Forms the exoskeleton structure of insects

Functions as a buffering agent to maintain a steady physiochemical condition of the body

How do humans affect the phosphorus cycle?

Human activities adversely affect the phosphorus cycle in the following ways:

Using of phosphate-containing fertilizers

Cutting down of tropical rain forests

Spilling of phosphate during transportation

Leaching of phosphorus from households and industries into water bodies

How does the use of fertilizer affect the phosphorus cycle?

Excessive use of phosphate fertilizers to enrich the soil also potentially increases the phosphorus content of the water bodies through surface runoff. This phenomenon leads to excessive growth of algae, thus lowering the dissolved oxygen level in the water bodies, resulting in severe loss of aquatic lives.

How does deforestation affect the phosphorus cycle?

Cutting down of trees increases soil erosion and thus decrease the phosphorus content of the soil. Since phosphorus acts as a limiting nutrient for plant growth, deforestation affects the phosphorus cycle.

What happens due to fluctuations of the phosphorus cycle in aquatic ecosystems?

An increase in the concentration of phosphorus will considerably boost the growth of algae within that ecosystem, causing a decline of oxygen content in the water, and thus major loss of aquatic life. On the other hand, a decrease in phosphorus concentration will deprive aquatic animals of the nutrient, limiting their growth.

Which parts of the phosphorus cycle are geological processes?

Weathering of rocks (the first step) and geological uplift (the last step) are the two geological processes that are part of the phosphorus cycle.

How is the phosphorus cycle different from the other biogeochemical cycles?

The global phosphorus cycle differs from other nutrient cycles in that it is a slow process and does not include any gaseous phase - a unique feature of this cycle.

How are the carbon and phosphorus cycle different?

Firstly, carbon and phosphorus cycles involve two different elements of carbon and phosphorus, respectively. The other major difference between the two is that the carbon cycle has an atmospheric component as carbon is available in the nature, whereas phosphorus needs to be created through the cycle.

How are the phosphorus and nitrogen cycles different?

The phosphorus cycle does not include an atmospheric component as phosphorus is not available in the nature, whereas nitrogen cycle occurs using the nitrogen in the atmosphere.

Article was last reviewed on Tuesday, March 3, 2020

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Phosphorus Cycle - Definition, Steps, Importance, With Diagram

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Biogeochemical process showing the movement of phosphorus and its different forms in nature with the help of living organisms is called the phosphorus cycle. Rocks, water, soil, and sediments constitute the primary nonliving sources of phosphorus, whereas plants and animals form the major living sources.

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Ozone Depleting Gas Index (ODGI) - NOAA Global Monitoring Laboratory

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The ODGI is an index that helps to quantify the health of the Earth’s ozone layer, and the amount of ozone depleting substances in the atmosphere

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In 2001, scientists predicted the Earth would warm by 1.4 - 5.8C by 2100.

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Issue

England's population is growing. That means what we need from our water system and sewerage network is changing.

We need to update our water systems and sewerage systems to adapt to these changes, and we need to make these updates safely and sustainably. That means planning for the future as well as looking after current requirements.

Actions

Drainage and sewers

We've transferred the ownership of private sewers from individual householders to sewerage companies. This has freed thousands of people from being charged for maintenance on pipes which they often didn't realise they were responsible for.

The Flood and Water Management Act 2010 contains powers to change the law so that water and sewage companies will be responsible for new sewers.

Surface water flooding can happen when, for example, rainwater gets into homes and businesses instead of draining away. We're planning to make changes so we can deal with surface water flooding better.

Over 2.8 million people are at risk from surface water flooding. We're introducing sustainable drainage systems to help them.

Water efficiency

We want to help people save water at home. We're doing this by:

We're making it more attractive for businesses to invest in equipment and technology that saves water. We're also working with water-saving experts such as the Waste and Resources Action Programme (WRAP) to help businesses to use water efficiently.

Safe drinking water

Defra is responsible for the laws and regulations designed to make sure all drinking water in England is safe, secure, and potable (good to drink).

The Drinking Water Inspectorate is responsible for keeping water companies and other people that supply drinking water within the law.

Water resource management

Our management of water resources aims to make best use of the water available across the country.

Read more about how we manage water.

Background

Our plans for future water management are set out in the white paper, Water for Life, published in 2011.

Appendix 1: water efficiency

This was a supporting detail page of the main policy document.

Water is a precious natural resource. It needs to be conserved to meet current and future demands. Population, household size and growth and affluence all affect how much water we use. Climate change could also put supplies under greater pressure in the future. This means that we need to use water more efficiently.

Everyone can help conserve water - from the biggest businesses to people in their own homes.

Domestic water efficiency

There are simple steps we can all take now to protect the UK's water supplies for the future. Here are some ways we can all use less water:

Kitchen

fix dripping taps

turn off the tap between rinsing dishes

only fill the kettle with the water you need

buy water-efficient dishwashers and washing machines

Bathroom

turn off the tap when brushing your teeth

take shorter showers

put a water-saving bag in the cistern

fit a flow regulator or an aerated shower head

fit flow regulators or aerators to taps

Garden

use a watering can or bucket and sponge, not a hosepipe

put a water butt in the garden

Others

install a leak detector

insulate water pipes

Waterwise has more water saving ideas.

Non-domestic water efficiency

Water-efficient enhanced capital allowances

The Enhanced Capital Allowance (ECA) scheme for water allows businesses to invest in water-efficient plant and machinery and write the cost off against tax. This can mean savings for the business and a positive effect on the environment.

The ECA scheme covers a variety of technologies. These include water-efficient taps, toilets and industrial cleaning equipment. For more on the eligible products, see the Water Technology List.

Waste and Resources Action Programme (WRAP)

We're working with the Waste and Resources Action Programme (WRAP) on a number of projects to improve water-efficiency in the non-domestic area.

For example, WRAP is helping the Food & Drink Federation with the Federation House Commitment (FHC). This is a project that helps companies in the food and drink sector reduce their use of water.

The food and drink industry is a major water user - it uses around 690 million litres of water a day. The FHC aims to cut the industry's water use by 20% by 2020.

Leakage

Getting water companies to reduce the amount of water they leak from their systems is an important part of conserving the UK's water supplies. Independent regulator Ofwat set all the water companies targets to reduce leakage. As a result, England and Wales have seen a 36% reduction in leakage since 1994.

Appendix 2: safe drinking water

This was a supporting detail page of the main policy document.

The government has a number of legal responsibilities covering drinking water. We have to:

We work with a number of agencies that monitor water and sewerage companies and drinking water quality. We also work with agencies who speak on behalf of water consumers.

Drinking Water Inspectorate

The Drinking Water Inspectorate (DWI) enforces drinking water standards in England and Wales.

DWI 's main job is to check that the water companies supply safe drinking water that meets the standards set down in law.

DWI 's Chief Inspector is appointed by the Secretary of State for Environment, Food and Rural Affairs and by Welsh ministers. The Chief Inspector acts independently of government.

Scotland and Northern Ireland have equivalent regulators:

DWI also acts as technical advisor for private water supplies.

Private water supplies

Not all the drinking water in England and Wales comes from the public network. Some communities - particularly in remote areas - can have their own supplies, with (for example) farms taking water from their own wells.

Private water supplies are regulated by different laws to public supplies. They're monitored for quality by local councils.

DWI provides support and advice to local councils on all aspects of drinking water quality, including private water supplies.

Ofwat

Ofwat makes sure water companies provide good service at a fair price. Ofwat does this by:

If a company doesn't come up to the standards Ofwat or the consumer expects, Ofwat can take action to protect consumers' interests. This can include legal action.

The Consumer Council for Water

The Consumer Council for Water (CCWater) is the voice of the water and sewerage consumer in England and Wales.

CCWater can take up a complaint if a consumer's not been able to resolve issues with a water company on their own.

Appendix 3: water resource management (current system)

This was a supporting detail page of the main policy document.

Managing future water needs

The law says that water companies have to supply potable (good to drink) water to all homes in England and Wales.

Water companies are also legally obliged to produce a plan every 5 years showing how they will:

Most water companies are planning to publish the final version of their latest plans (covering 2015 to 2040) later in 2014. The companies will begin consulting on their next plans in 2018.

You can read the water companies' current water resources plans on their websites.

Water abstraction management

Water abstraction means removing water from water-bodies. These include lakes, rivers or aquifers.

Most water abstraction needs a licence from the Environment Agency.

The Environment Agency also has guidance on impounding licences. You'll usually need an impounding licence if you want to construct, alter or operate a dam or weir.

Abstraction or impoundment licences contain conditions that protect the environment, other abstractors and water users. The Environment Agency carries out on-site inspections and checks that licence holders are complying with the conditions in their abstraction or impoundment licence.

If an abstraction is causing or could cause damage to the environment, the Environment Agency may make a proposal to change it or revoke it. If the Environment Agency finds someone is not complying with their licence, action will range from giving advice and guidance to prosecuting in the most serious cases.

Defra and the Welsh Government are working with the Environment Agency, Ofwat, and other partners to reform the water abstraction system. The system hasn't changed substantially since the 1960s. Read more about abstraction reform.

Drought

Despite our reputation as a rainy country, we have to be prepared for drought.

All water companies are legally required to produce drought plans. You can read these on the water companies' websites.

During a drought, water companies can restrict non-essential use of water. These are commonly known as hosepipe bans. The relevant legislation for these water restrictions can be found in:

Water companies may also apply for either a drought permit or a drought order to allow them to restrict demand for water or to maintain public water supplies. Drought permits allow companies to take water from new sources. They can also alter restrictions on existing abstractions.

Drought orders can go further in restricting non-essential use of water. The Drought Direction 2011 lists the uses of water which can be banned under an ordinary drought order.

The Environment Agency (EA) has a duty to manage water resources in England.

The Environment Agency routinely measures, monitors and reports on the water situation across England. This helps them to assess the national and local water situation and the prospects of any water shortages for the environment.

During a drought the Environment Agency:

increases monitoring plans to make sure that they continue to protect the environment from harm

makes sure that water companies and other water users do not take too much water and that they are following their drought plans

deals with drought permit applications to allow water companies to continue supplying water during a drought whilst limiting the impact on the environment

reports on the state of water resources during a drought to the public, government and our partners

co-ordinates a communications and media strategy to ensure the correct messages are being communicated to the areas affected by the drought

Drought plans

The Environment Agency has drought plans for England. They set out how the Environment Agency will manage water resources for the environment and people during a drought. These plans aim to balance the interests of the environment, business and public water supply. They help the EA and water users to make the right decisions at the right time.

Appendix 4: drainage and sewers

This was a supporting detail page of the main policy document.

Thames Tideway Tunnel

London's sewerage network was built in the 19th century. The capital's population then was 4 million. It's now over 7 million, and the network is almost at full capacity.

As a result, currently around 20 million tonnes of untreated waste water overflows into the River Thames in London each year. This has significant environmental effects: it kills large numbers of fish and causes health risks for river users.

On 12 September 2014 the Secretaries of State for Communities and Local Government and for Environment, Food and Rural Affairs gave permission for the Thames Tideway Tunnel project. This permission took the form of a development consent order made under section 114 of the Planning Act 2008. Full information on the decision, including the Planning Inspectorate Examining Authority's report, is available on the Planning Inspectorate's web site.

The tunnel project is sponsored by Thames Water plc. In June 2014, Ministers specified the tunnel project under the 2013 Specified Infrastructure Projects Regulations. This requires Thames Water to get an independent company to finance and build the bulk of the tunnel. It is done through a competitive tender process. Thames Water has started the process and is expected to have awarded the contract by mid 2015.

Construction of the tunnel is scheduled to start in 2016 and finish in 2023.

The need for the tunnel was set out in the government's National Policy Statement for Waste Water issued in 2012.

You can read more about the Thames Tideway Tunnel on Thames Water's website.

Ownership of private sewers

On October 1 2011 the Water Industry (Schemes for Adoption of Private Sewers) Regulations 2011 became law.

This meant that the maintenance of private sewers connected to the public sewer network on 1 July 2011 became the responsibility of the water and sewerage companies.

The transfer means customers now have a regulated company responsible for maintaining and repairing the sewers attached to their property. These companies have to work to minimum standards overseen by Ofwat.

The change also means:

New sewers

We're planning to make all new sewers for new properties and re-developments the responsibility of the water and sewerage companies.

The powers to make this change are set out in section 42 of the Flood and Water Management Act 2010.. When implemented, it will mean that new sewers from new properties will be owned and maintained by the appropriate water and sewerage company. The act also allows building standards to be set for new sewers.

We consulted on this policy in 2012. Defra intends to implement section 42 of the act at the earliest possible opportunity. We will continue to look for evidence to support the implementation of the policy, including the impact on business.

Surface water flooding

We're making plans to reduce surface water flooding.

Surface water flooding happens when rainfall doesn't soak into the ground, but flows rapidly into the sewer system instead. This can lead to flooding. The worst effects are often in built-up areas where much of the ground is covered with non-porous materials such as concrete.

Around 2.8 million people in England and Wales are at risk from surface water flooding.

We're planning to increase the use of sustainable drainage systems (commonly known as SuDS) to reduce surface water flooding. Sustainable drainage systems help by slowing the rate at which areas flood and by reducing the amount of surface water entering sewers.

Examples of sustainable drainage systems include:

using surfaces such as gravel or permeable (porous) paving blocks to allow water to soak into the ground

using basins or ponds to reduce the amount of water that flows away

We asked for views on proposals to increase the number of sustainable drainage systems in England. Our response was published on 18 December 2014.

In the light of this, we set out in a statement to Parliament changes to planning that will apply for major development from 6 April 2015.

We send out regular SuDS newsletters. If you want to be added to the mailing list, please email SUDS@defra.gsi.gov.uk.

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2010 to 2015 government policy: water and sewerage services

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England's population is growing. That means what we need from our water system and sewerage network is changing. We need to update our water systems and sewerage systems to adapt to these changes, and we need to make these updates safely and sustainably. That means planning for the future as well as looking after current requirements.

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Projections of how and where water stress will increase across the world as environmental changes and population increases take effect.

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BBC NEWS | Asia-Pacific | Central Asia fails in water talks

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The leaders of the five Central Asian states fail to reach a deal on sharing water resources - one of the region’s key issues.

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The hydrologic cycle is a conceptual model that describes the storage and movement of water between the ,atmosphere , lithosphere , and the hydrosphere (see Figure 8b-1). Water on this planet can be stored in any one of the following reservoirs:atmosphere , , , , , , snowfields , andgroundwater .

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Climate change: US megadrought 'already under way'

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Climate change: US megadrought 'already under way'

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A drought, equal to the worst to have hit the western US in recorded history, is already under way, say scientists.

Researchers say the megadrought is a naturally occurring event that started in the year 2000 and is still ongoing.

Climate change, though, is having a major impact with rising temperatures making the drought more severe.

Some researchers are more cautious, saying that it is too early to say if the region really is seeing a true megadrought.

So what exactly is a megadrought?

According to the authors of this new paper, a megadrought in North America refers to a multi-decade event, that contains periods of very high severity that last longer than anything observed during the 19th or 20th centuries.

The authors say there have been around 40 drought events over the period from 800-2018 in the western US.

Of these, only four meet the criteria for a megadrought.

These were in the late 800s, the mid-1100s, the 1200s and the late 1500s.

How do researchers know what drought conditions were like in the past?

The key to this new study is the use of tree ring records to reconstruct soil moisture data for the past 1200 years.

The team were also able to use supporting evidence such as medieval tree stumps growing in normally wet river beds, the abandonment of settlements by indigenous civilisations at the peak of the 13th century drought, plus evidence from lake deposits indicating wildfire activity was enhanced during these drought periods.

What did the study find?

The researchers discovered that when they compared the worst 19-year drought events in the past to soil moisture records from 2000-2018, the current period is already worse than three of the four megadroughts recorded.

The fourth one, which ran from 1575 to 1603 was likely the worst one of all, but the difference with the present event is slight.

"The first two decades of this drought look just like the first two decades of all of the mega droughts," said lead author Dr Park Williams, from Columbia University in New York.

"In fact, it is essentially tied with the worst two decades of the worst of the mega droughts."

Is the current megadrought a natural event or was it caused by climate change?

The authors say that undoubtedly the current drought situation is a natural event but is being made much worse by climate change.

The key event seems to have been the El Niño/La Niña weather phenomenon.

"We know from, from many lines of evidence that when you have La Niña type conditions in the tropical Pacific Ocean, then the southwestern US and northern Mexico get dry. And that's what we've seen over the last two decades," said Dr Williams.

But climate change has super-charged the current drought.

The authors say that in the western US, temperatures have gone up by 1.2C since 2000. Hotter air holds more moisture and that moisture is being pulled out of the ground.

They believe that climate change is responsible for about half of of the pace and severity of the current event.

"It doesn't matter if this is exactly the worst drought ever," said co-author Benjamin Cook, who is affiliated with Columbia University and Nasa's Goddard Institute for Space Studies.

"What matters is that it has been made much worse than it would have been because of climate change."

What have been the impacts of the megadrought?

The authors say the two most important water reservoirs in the region, Lake Powell and Lake Mead have both shrunk dramatically during the drought. Wildfires across the region are growing in area.

"At any given year, there's over ten times more forest area burns than we would have expected in a given year, 40 years ago," said Dr Williams.

What has helped to mitigate the impact of the drought has been groundwater - the water held underground in aquifers.

This has increasingly been used to bolster supplies for agriculture.

The longer the drought goes on, the deeper into these reserves that people are digging, and they take a long time to replenish.

Is there full agreement among scientists that a megadrought is taking place right now?

No. This new study is contentious, especially as the definition of what exactly a megadrought means is still being argued over.

Some say that it is also way too early to declare that a megadrought is ongoing.

But even those who disagree with the idea, acknowledge there is water stress in the region and this is likely to get worse in the future.

"Whether or not the western US has crossed a threshold into an event that goes by any specific label, what's been clear this century is that water is an essential resource in the western US, and it's a precarious one, because the region can have long spells with little precipitation," said Dr Angeline Pendergrass, a scientist with the US National Center for Atmospheric Research (NCAR).

"And it looks like climate change won't make it better - indeed, it will likely make it worse."

The study has been published in the journal Science.

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A drought, equal to the worst to have hit the western US in recorded history, is already under way, say scientists. Researchers say the megadrought is a naturally occurring event that started in the year 2000 and is still ongoing. Climate change, though, is having a major impact with rising temperatures making the drought more severe.

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