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Will the ocean ever run out of fish? - Ayana Elizabeth Johnson and Jennifer Jacquet

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What Is NOISE POLLUTION? | What Causes Noise Pollution? | The Dr Binocs Show | Peekaboo Kidz

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Climate 101: Deforestation | National Geographic

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How population growth impacts the planet

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How population growth impacts the planet

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How population growth impacts the planet

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How population growth impacts the planet

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How population growth impacts the planet

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How population growth impacts the planet

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Air Pollution | Video for Kids | Causes, Effects & Solution

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Air pollution happens when solid and liquid particles-called aerosols -and certain gases end up in our air. These particles and gases can be bad for the planet and for our health, so keeping track of them is important.

Where do aerosols come from?

Any particle that gets picked up into the air or is formed from chemical reactions in the air can be an aerosol. Many aerosols enter the atmosphere when we burn fossil fuels-such as coal and petroleum-and wood. These particles can come from many sources, including car exhaust, factories and even wildfires. Some of the particles and gases come directly from these sources, but others form through chemical reactions in the air.

Aerosols can come from other places, too, such as ash from an erupting volcano. Dust, pollen from plants and mold spores are also examples of aerosols.

What else causes air pollution?

Certain gases in the atmosphere can cause air pollution. For example, in cities, a gas called ozone is a major cause of air pollution. Ozone is also a greenhouse gas that can be both good and bad for our environment. It all depends where it is in Earth's atmosphere.

Ozone high up in our atmosphere is a good thing. It helps block harmful energy from the Sun, called radiation. But, when ozone is closer to the ground, it can be really bad for our health. Ground level ozone is created when sunlight reacts with certain chemicals that come from sources of burning fossil fuels, such as factories or car exhaust.

When particles in the air combine with ozone, they create smog. Smog is a type of air pollution that looks like smoky fog and makes it difficult to see.

How does air pollution affect Earth's climate?

Aerosols can impact how the Sun's light hits Earth. For example, some aerosols reflect sunlight while others absorb sunlight. It depends on the color of the particle.

Dark surfaces-whether it's a black t-shirt or a dark particle in the atmosphere-absorb the Sun's heat. Lighter-colored surfaces reflect heat from the Sun.

A white t-shirt reflects the Sun on a hot day, making you feel cooler. In the same way, light-colored particles that reflect the Sun's light and heat away from Earth can make the global temperature cooler. Dark-colored particles that absorb the Sun's light can make the global temperature warmer.

How does air pollution affect our health?

Breathing in polluted air can be very bad for our health. Long-term exposure to air pollution has been associated with diseases of the heart and lungs, cancers and other health problems. That's why it's important for us to monitor air pollution.

How is NASA monitoring air pollution?

NASA uses satellites orbiting Earth to keep an eye on air pollution. In fact, air quality forecasters use information about aerosols from NASA's Aqua, Terra and Suomi-NPP satellites.

NASA also is developing a new instrument called the Multi-Angle Imager for Aerosols, or MAIA, to fly aboard a future spacecraft mission. MAIA will help scientists understand the size, makeup and quantity of aerosols in our air. Eventually, scientists will be able to compare this information with health records. This can help us better understand the relationship between aerosol pollution and human health.

Related NASA Missions

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Air pollution is caused by solid or liquid particles and certain gases suspended in the air. These particles and gases can come from car and truck exhaust, factories, dust, pollen, mold spores, volcanoes and wildfires.

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Air pollution is a type of environmental pollution that affects the air and is usually caused by smoke or other harmful gases, mainly oxides of carbon, sulphur, and nitrogen.

Many of the world's large cities today have polluted air or low air quality.

Even 2,000 years ago, the Romans were complaining about the polluted air in their cities. At that time, the air was thick with smoke from fires and the smell of sewers. Air pollution has been classified as a danger to human health and Earth's many ecosystems for a long time.

Air quality

Pollution can be in the form of a gas, liquid, or solid. It can also be classified chemically, such as oxides, hydrocarbons, acids, or other kinds of chemicals.

Many pollutants go into the air from natural sources. These pollutants include dust, sea salt, volcanic ash and gases, smoke from forest fires, pollen, and many other materials.

Primary and secondary pollutants

Air pollution is usually described as either a primary pollutant or a secondary pollutant. Primary pollutants are pollutants that are put directly into the air by humans or natural sources. Examples of primary pollutants are exhaust fumes ( gas) from cars, soot from smoke, dust storms, and ash from volcanic eruptions (as seen in the picture on the left).

Secondary pollutants are pollutants that are made from chemical reactions when pollutants mix with other primary pollutants or natural materials like water vapor. Many secondary pollutants are made when a primary pollutant reacts with sunlight. Ozone and smog are secondary pollutants. Ozone is a gas that stops harmful ultraviolet rays from the sun. When it is near the ground, though, it can poison people and other organisms.

Human-made air pollution comes from many things. Most air pollution made by humans today is because of transportation. Automobiles, for instance, make up about 60% of human-made air pollution. The gases inside car exhaust, like nitrogen oxide, make smog and acid rain.

Farmlands and forests sometimes burn in wildfires, producing soot (a black powder made mainly of carbon and produced when coal, grasses, wood, etc. is burned) from the smoke. Soot can affect people and other life forms.

Industrial air pollution

Many industrial power plants burn fossil fuels to get their energy. However, burning fossil fuels can make a lot of oxides ( chemical compounds that have oxygen and other elements inside). The burning of fossil fuels makes 96% of the sulfur oxides in the atmosphere. Some industries also make chemicals that make poisonous fumes (smoke).

Indoor air pollution

Air pollution does not only happen outside. The insides of homes, schools, and buildings can also have air pollution. Sometimes the air inside a building, especially if its windows are closed, is even worse than the air outside. Many things that humans use every day can pollute the air. Compounds inside carpets, paints, building materials, and furniture also pollute the air, especially when they are new.

Acid precipitation

Acid precipitation is precipitation, like rain, sleet, or snow, that contains acids from air pollution. When fossil fuels are burned, they let out oxides into the air. When these oxides mix with water in the atmosphere, they make acid, which falls as precipitation. Acid precipitation can kill living things like fish and trees by making the place where they live too acidic. Acid rain can also damage buildings made of limestone and concrete.

A worldwide concern is the hole in the ozone layer in the stratosphere. The Earth's ozone layer protects life from the sun's harmful ultraviolet rays, but in the 1970s, scientists found out that some chemicals let out into the atmosphere makes the ozone turn into oxygen. This lets more ultraviolet rays reach the Earth. During the 1980s, scientists found that the ozone layer above the South Pole had thinned by 50 to 98%.

Human health

On March 17, 1992, in Mexico City, all children under the age of 14 were not allowed to go to school because of air pollution. This does not happen often, but being exposed to air pollution every day can cause people to have many health problems. Children, elderly (old) people, and people with allergies can develop health problems because of air pollution. Studies from the University of Birmingham showed that air pollution from motor vehicles could be the cause of some pneumonia-related deaths.

The World Health Organization said that 2.4 million people died because of problems that air pollution causes. Some of the problems include:

Agricultural effects

India published a report in 2014 that showed that air pollution in 2010 had cut the amount of crops harvested by almost half in the most affected areas when compared to 1980 levels. Sometimes, crops can produce better when air quality improves.

Interesting facts about air pollution

Air pollution is caused by human and natural contributors. Industries, mining, factories, vehicles, forest fires, volcanic eruptions, and wind erosion can all cause air pollution.

92% of the world's population live in areas in which air pollution is higher than safe limits.

Inhaling air pollution is thought to take away 1-2 years of an average human life.

Babies whose mothers live in high-traffic areas have a 22% higher risk of being born with poor lung function than those whose mothers live in less polluted areas.

Air pollution is more dangerous for children because of their smaller size and lung capacity.

The IQ of children can be negatively affected by air pollution.

ADHD can worsen or be caused by Polycyclic aromatic hydrocarbons (PAH).

Waiting in traffic and breathing in the air pollution is thought to increase a person's chance of death due to a heart attack.

The 1952 Great Smog of London is said to have killed 8,000 people.

Scientists have guessed that by 2050, six million people per year will die as a result of air pollution.

Larger cities control the amount of emissions allowed from vehicles to help reduce air pollution and protect the public.

Deforestation is a major cause of air pollution.

Images for kids

In Spanish: Contaminación atmosférica para niños

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Air pollution is a type of environmental pollution that affects the air and is usually caused by smoke or other harmful gases, mainly oxides of carbon, sulphur, and nitrogen.

Many of the world's large cities today have polluted air or low air quality.

Even 2,000 years ago, the Romans were complaining about the polluted air in their cities. At that time, the air was thick with smoke from fires and the smell of sewers. Air pollution has been classified as a danger to human health and Earth's many ecosystems for a long time.

Air quality

Pollution can be in the form of a gas, liquid, or solid. It can also be classified chemically, such as oxides, hydrocarbons, acids, or other kinds of chemicals.

Many pollutants go into the air from natural sources. These pollutants include dust, sea salt, volcanic ash and gases, smoke from forest fires, pollen, and many other materials.

Primary and secondary pollutants

Air pollution is usually described as either a primary pollutant or a secondary pollutant. Primary pollutants are pollutants that are put directly into the air by humans or natural sources. Examples of primary pollutants are exhaust fumes ( gas) from cars, soot from smoke, dust storms, and ash from volcanic eruptions (as seen in the picture on the left).

Secondary pollutants are pollutants that are made from chemical reactions when pollutants mix with other primary pollutants or natural materials like water vapor. Many secondary pollutants are made when a primary pollutant reacts with sunlight. Ozone and smog are secondary pollutants. Ozone is a gas that stops harmful ultraviolet rays from the sun. When it is near the ground, though, it can poison people and other organisms.

Human-made air pollution comes from many things. Most air pollution made by humans today is because of transportation. Automobiles, for instance, make up about 60% of human-made air pollution. The gases inside car exhaust, like nitrogen oxide, make smog and acid rain.

Farmlands and forests sometimes burn in wildfires, producing soot (a black powder made mainly of carbon and produced when coal, grasses, wood, etc. is burned) from the smoke. Soot can affect people and other life forms.

Industrial air pollution

Many industrial power plants burn fossil fuels to get their energy. However, burning fossil fuels can make a lot of oxides ( chemical compounds that have oxygen and other elements inside). The burning of fossil fuels makes 96% of the sulfur oxides in the atmosphere. Some industries also make chemicals that make poisonous fumes (smoke).

Indoor air pollution

Air pollution does not only happen outside. The insides of homes, schools, and buildings can also have air pollution. Sometimes the air inside a building, especially if its windows are closed, is even worse than the air outside. Many things that humans use every day can pollute the air. Compounds inside carpets, paints, building materials, and furniture also pollute the air, especially when they are new.

Acid precipitation

Acid precipitation is precipitation, like rain, sleet, or snow, that contains acids from air pollution. When fossil fuels are burned, they let out oxides into the air. When these oxides mix with water in the atmosphere, they make acid, which falls as precipitation. Acid precipitation can kill living things like fish and trees by making the place where they live too acidic. Acid rain can also damage buildings made of limestone and concrete.

A worldwide concern is the hole in the ozone layer in the stratosphere. The Earth's ozone layer protects life from the sun's harmful ultraviolet rays, but in the 1970s, scientists found out that some chemicals let out into the atmosphere makes the ozone turn into oxygen. This lets more ultraviolet rays reach the Earth. During the 1980s, scientists found that the ozone layer above the South Pole had thinned by 50 to 98%.

Human health

On March 17, 1992, in Mexico City, all children under the age of 14 were not allowed to go to school because of air pollution. This does not happen often, but being exposed to air pollution every day can cause people to have many health problems. Children, elderly (old) people, and people with allergies can develop health problems because of air pollution. Studies from the University of Birmingham showed that air pollution from motor vehicles could be the cause of some pneumonia-related deaths.

The World Health Organization said that 2.4 million people died because of problems that air pollution causes. Some of the problems include:

Agricultural effects

India published a report in 2014 that showed that air pollution in 2010 had cut the amount of crops harvested by almost half in the most affected areas when compared to 1980 levels. Sometimes, crops can produce better when air quality improves.

Interesting facts about air pollution

Air pollution is caused by human and natural contributors. Industries, mining, factories, vehicles, forest fires, volcanic eruptions, and wind erosion can all cause air pollution.

92% of the world's population live in areas in which air pollution is higher than safe limits.

Inhaling air pollution is thought to take away 1-2 years of an average human life.

Babies whose mothers live in high-traffic areas have a 22% higher risk of being born with poor lung function than those whose mothers live in less polluted areas.

Air pollution is more dangerous for children because of their smaller size and lung capacity.

The IQ of children can be negatively affected by air pollution.

ADHD can worsen or be caused by Polycyclic aromatic hydrocarbons (PAH).

Waiting in traffic and breathing in the air pollution is thought to increase a person's chance of death due to a heart attack.

The 1952 Great Smog of London is said to have killed 8,000 people.

Scientists have guessed that by 2050, six million people per year will die as a result of air pollution.

Larger cities control the amount of emissions allowed from vehicles to help reduce air pollution and protect the public.

Deforestation is a major cause of air pollution.

Images for kids

In Spanish: Contaminación atmosférica para niños

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Overfishing is catching too much fish. It is a type of overexploitation where fish stocks are reduced to low levels. It is a good example of what is good for the short term is not good for the long term. Also, what is good for some fishermen is not good for all of them ( tragedy of the commons).

So much fish is caught that there are too few adults of certain species left. With cod, for example, the greatest production of eggs is from large females. But these are caught, and the average size of spawning females has gone down. Eventually this gets so that the production of eggs is significantly reduced. The artificial selection of large fish has gradually reduced the size of mature females.

The Northwest Atlantic cod has been regarded as heavily overfished throughout its range, resulting in a crash in the fishery in the United States and Canada during the early 1990s.

Consumers can get information about the conservation status of the seafood available to them.

Related pages

Images for kids

Overfishing scores range from 1-7; 7=highest level of overfishing

Overfishing can deplete key reef species and damage coral habitat. Coral reef fish are a significant food source for over a billion people worldwide.

The Traffic Light colour convention, showing the concept of Harvest Control Rule (HCR), specifying when a rebuilding plan is mandatory in terms of precautionary and limit reference points for spawning biomass and fishing mortality rate.

The Chinese paddlefish, once common to the Yangtze River, has gone extinct due to overfishing and dam construction

In Spanish: Sobrepesca para niños

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Overpopulation means that the population of a place is too high. Specifically, there are too many organisms of a certain species in a habitat, so the number of organisms living there is larger than the carrying capacity of the habitat. The habitat cannot support these numbers over time without hurting itself.

The term "overpopulation" is most often used to refer to the number of humans living on Earth.

Human overpopulation

The world's population has greatly increased in the last 50 years. The main reason is the reduction in death rate, especially for infants and children. The result is that many more people survive to the age when reproduction is possible.

1. By reducing the effect of infectious diseases

1. widespread use of antibiotics against bacterial diseases

2. increased use of vaccination against some viral diseases

3. wider provision of clean water (modern sewage systems etc.), which reduces parasitic diseases.

2. By increasing food production

1. the world-wide use of DDT, and later anti-pest treatments.

2. the invention of high-yielding varieties of crops and later, genetically-engineered crops.

Steve Jones, head of the biology department at University College London, has said,

"Humans are 10,000 times more common than we should be, according to the rules of the animal kingdom, and we have agriculture to thank for that. Without farming, the world population would probably have reached half a million by now".

Against this background, the reduction in fertility has had little effect, except perhaps in China. The use of the contraceptive pill has transformed the lives of women in rich countries, but has made little impact in poor ones.

The recent rapid increase in human population over the past two centuries has raised concerns that humans are beginning to overpopulate the Earth. The planet may not be able to sustain larger numbers of people. The population has been growing since the end of the Black Death, around the year 1400. At the beginning of the 19th century, it had reached roughly 1,000,000,000 (one billion). Rapid population growth occurred all over the world, especially after World War II. By 1960, the world population had reached 3 billion, and it doubled to 6 billion over the next four decades. As of 2011, the estimated annual growth rate was 1.10%, down from a peak of 2.2% in 1963, and the world population stood at roughly 6.9 billion. In 2014, it is over seven billion.

Current projections show a steady decline in the population growth rate, with the population expected to reach between 8 and 10.5 billion between the year 2040 and 2050.

The scientific consensus is that the present population growth and increase in use of resources is a threat to the ecosystem. The InterAcademy Panel Statement on Population Growth called the growth in human numbers "unprecedented", and stated that many environmental problems, such as rising levels of atmospheric carbon dioxide, global warming, and pollution, were made worse by the population expansion. At the time, the world population stood at 5.5 billion, and optimistic scenarios predicted a peak of 7.8 billion by 2050, a number that current estimates show will be reached around 2030.

Potential solutions

The solutions usually suggested are better education and widespread free contraception (birth control). Many pregnancies are unplanned (40%) or unwanted.

There are powerful forces working against birth control. Religious and traditional beliefs often favor large families. Few governments have tackled the problem seriously.

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Overpopulation means that the population of a place is too high. Specifically, there are too many organisms of a certain species in a habitat, so the number of organisms living there is larger than the carrying capacity of the habitat. The habitat cannot support these numbers over time without hurting itself.

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Deforestation is when forests are destroyed by cutting trees ( logging) and not replanting them. The most common reason is to clear the land to make farms, ranches, and cities. Trees are also cut for firewood and lumber.

Deforestation destroys the habitat of many animals, leading to their death and possible extinction. The loss is more severe in primary forests, which are forests that have yet been untouched by humans. Deforestation also releases sequestered carbon.

Restoring trees in deforested places is called reforesting.

Benefit of forests

Forests are often planted to protect against natural disasters. They also help the water cycle function properly. When forests are lost, very often the soil they protected is also lost. This loss of soil is called erosion.

Trees are also important for carbon sequestration. They are important in keeping the proper balance of oxygen (O ₂) and carbon dioxide (CO ₂) on earth. They take in carbon dioxide that humans exhale (breathe out) and release oxygen that humans inhale (breathe in).

Forests have the following functions:

regulating the water cycle

producing soil

preventing soil erosion

providing habitat for animals

providing most of our oxygen

maintaining the proper oxygen (O₂) and carbon dioxide (CO₂) levels

balancing the atmosphere

regulating the temperature

Global deforestation suddenly increased around 1852. As of 1947, the planet had 5.8 million to 6.2 million sq. mi. (15 million to 16 million km ²) of mature tropical forests (forested landscapes in tropical regions), but by 2015, it was estimated that about half of these had been destroyed. Total land coverage by tropical rainforests decreased from 14% to 6%. Much of this loss happened between 1960 and 1990. Scientists have calculated that at this rate, the extinction of such forests could happen by the mid-21st century.

Causes of deforestation

Land has other uses besides growing trees. The biggest uses of land that was once forested are for farming and ranching. Some land is also used for roads and buildings, especially in urban areas. As the population grows, people need to remove more trees. They also use the wood from the trees as lumber to make buildings and other things, or they burn the trees as firewood.

Environmental effects

Atmospheric

Further information: Deforestation and climate change

Deforestation is ongoing and is shaping climate and geography.

When the trees burn or rot, the small amount of carbon that is not absorbed by the soil can return to the atmosphere in the form of carbon dioxide. Scientists believe that since carbon dioxide is a greenhouse gas, deforestation can cause global warming. They have estimated that tropical deforestation is responsible for about 20% of world greenhouse gas emissions.

Hydrological

The water cycle is also affected by deforestation. Trees play an important part in the proper working of the water cycle.

Their canopies catch precipitation, which is then evaporated back to the atmosphere (canopy interception). Without canopy interception, the air would be drier and less precipitation would fall.

Their litter (plant material on the ground around the tree), stems, and trunks slow down surface runoff. Without these, flash flooding would be more likely.

Their roots create macropores - large pipe-like trails - in the soil that increase infiltration of water. Without these trails, water would not flow through the soil as easily.

They absorb groundwater from the soil and transpire moisture into the atmosphere. Without transpiration, the air would be drier and trees would not get the moisture they need because of the lack of precipitation.

Tropical rainforests produce about 30% of our planet's fresh water.

Deforestation changes normal weather patterns, creating hotter and drier weather. This results in more drought, crop failures, melting of polar ice caps, and coastal flooding.

Undisturbed forests do not have much erosion because of plant litter on the ground. Plant litter protects from surface runoff. Forestry operations also increase erosion because of the roads and mechanical equipment they use.

Deforestation in China's Loess Plateau many years ago led to soil erosion. This erosion caused valleys to open. The increase of soil in the runoff causes the Yellow River to flood and makes it yellow-colored.

Erosion is not always a consequence of deforestation. An example would be the southwestern regions of the United States. The loss of grass due to the presence of trees and other shrubbery leads to more erosion than when trees are removed.

Soils are reinforced by the presence of trees, which secure the soil by binding their roots to soil bedrock. When trees are removed on sloped lands, those lands are more likely to have a landslide.

Biodiversity

Forests support biodiversity, providing a habitat for wildlife. Forests also produce medicinal plants. Tropical rainforests are the most diverse ecosystems on Earth and about 80% of the world's known biodiversity could be found in tropical rainforests. When humans remove or destroy large areas of forest cover, the soil degrades and biodiversity is lessened. Some species of plants and animals can become extinct. Some scientists predict that more than 40% of the animal and plant species in Southeast Asia could be wiped out in the 21st century. Other scientists show data that disagree with this prediction.

Health effects

Public health context

Some scientists believe that deforestation exposes people to zoonotic diseases (diseases that can be passed from an animal to a human). Dieseases that are associated with the forest include malaria, Chagas disease (also known as American trypanosomiasis), African trypanosomiasis ( sleeping sickness), leishmaniasis, the Nipah virus, Avian flu, Swine Flu, Lyme disease, HIV, and Ebola.

General overview

According to the World Economic Forum, 31% of emerging diseases are linked to deforestation. According to the US Centers for Disease Control and Prevention (CDC), 75% of emerging diseases in humans came from animals.

In 2016, the United Nations Environment Programme published the UNEP Frontiers 2016 Report. The report shows the causes of emerging diseases:

The latest appearing diseases and their causes are listed on page 23 of the report:

Economic impact

According to the World Economic Forum, half of the global GDP depends on nature. For every dollar spent on nature restoration, there is a profit of at least 9 dollars.

People in both developed and developing countries use wood for building, wood for fuel, and wood pulp for paper. In developing countries, almost three billion people rely on wood for heating and cooking. The economy does well in the short term when trees are cut to make products, but usually, not enough trees can be planted in their place in time for more to be cut down again when they are needed. This causes the economy in the long term to suffer.

Illegal logging causes billions of dollars of losses to national economies each year. The European Union is one of the largest importers of products made from illegal deforestation.

Many countries have taken steps to control deforestation. They have begun programs that they hope will help with the problem.

Reducing emissions: The United Nations and the World Bank have begun to develop programs to reduce deforestation. Because trees take in carbon dioxide, the more trees we have, the less CO₂ will be emitted into the air. Reducing Emissions from Deforestation and Forest Degradation (REDD) is a program that offers money or other incentives (good consequences as a result of an action) to developing countries if they use different ways to build than using the forest's trees.

Government and private policies: In the government area, laws could be made to protect forests, making it illegal to cut trees down without special permission. Private companies could promise to use the land they own the best way they can and to buy products only from companies that do not use deforestation. The Paris Agreement is an example of this.

Land rights: Another way to conserve forests is to change the right to use the land from the public domain to the indigenous inhabitants.

Farming practices: New ways to farm are being developed to get more use out of a single piece of land rather than having to use many pieces of land for different purposes. For instance, in cyclic agriculture, cattle are grazed on farmland that is resting and rejuvenating. The cattle help the land prepare for future plantings by dropping nutrients (from their feces) into the soil.

Monitoring deforestation: Satellite images can help scientists know where on the earth they need to concentrate their efforts in fighting deforestation.

Forest management: Planning ahead by planting more trees than we think will be necessary for future generations is one way to manage our forests well. Reforestation in areas where trees have been cut is another way to manage our forests well. In the areas where "slash-and-burn" is practiced, switching to "slash-and-char" would make the soil rich and healthy for future trees.

Sustainable practices: Bamboo grows and is ready for use faster than trees. Using bamboo rather than wood for building and making products would reduce the need to cut down trees.

Forest plantations: Some places have forest plantations, which are large plots of land that have trees planted on them in an orderly way. They produce more healthy trees per acre than a natural forest.

Interesting facts about deforestation

More than half the world's tropical forests have been destroyed since the 1960s.

In 2019, the world lost an entire soccer field worth of primary rainforest every six seconds.

Forests release carbon dioxide when they are cleared or burned. About 12 percent of global greenhouse gas emissions come from deforestation.

It is estimated that within 100 years, there will be no rainforests.

20% of the world's oxygen is produced in the Amazon forest.

Almost half of the world's timber and up to 70% of paper is consumed by Europe, the United States, and Japan alone.

Worldwide, more than 1.6 billion people rely on forest products for all or part of their livelihoods.

Related pages

Images for kids

In Spanish: Deforestación para niños

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Noise pollution is an invisible danger. It cannot be seen, but it is present nonetheless, both on land and under the sea. Noise pollution is considered to be any unwanted or disturbing sound that affects the health and well-being of humans and other organisms.

Sound is measured in decibels. There are many sounds in the environment, from rustling leaves (20 to 30 decibels) to a thunderclap (120 decibels) to the wail of a siren (120 to 140 decibels). Sounds that reach 85 decibels or higher can harm a person's ears. Sound sources that exceed this threshold include familiar things, such as power lawn mowers (90 decibels), subway trains (90 to 115 decibels), and loud rock concerts (110 to 120 decibels).

Noise pollution impacts millions of people on a daily basis. The most common health problem it causes is Noise Induced Hearing Loss (NIHL). Exposure to loud noise can also cause high blood pressure, heart disease, sleep disturbances, and stress. These health problems can affect all age groups, especially children. Many children who live near noisy airports or streets have been found to suffer from stress and other problems, such as impairments in memory, attention level, and reading skill.

Noise pollution also impacts the health and well-being of wildlife. Studies have shown that loud noises can cause caterpillars' dorsal vessels (the insect equivalent of a heart) to beat faster, and cause bluebirds to have fewer chicks. Animals use sound for a variety of reasons, including to navigate, find food, attract mates, and avoid predators. Noise pollution makes it difficult for them to accomplish these tasks, which affects their ability survive.

Increasing noise is not only affecting animals on land, it is also a growing problem for those that live in the ocean. Ships, oil drills, sonar devices, and seismic tests have made the once tranquil marine environment loud and chaotic. Whales and dolphins are particularly impacted by noise pollution. These marine mammals rely on echolocation to communicate, navigate, feed, and find mates, and excess noise interferes with their ability to effectively echolocate.

Some of the loudest underwater noise comes from naval sonar devices. Sonar, like echolocation, works by sending pulses of sound down into the depths of the ocean to bounce off an object and return an echo to the ship, which indicates a location for object. Sonar sounds can be as loud as 235 decibels and travel hundreds of miles under water, interfering with whales' ability to use echolocation. Research has shown that sonar can cause mass strandings of whales on beaches and alter the feeding behavior of endangered blue whales ( Balaenoptera musculus). Environmental groups are urging the U.S. Navy to stop or reduce using sonar for military training.

Seismic surveys also produce loud blasts of sound within the ocean. Ships looking for deep-sea oil or gas deposits tow devices called air guns and shoot pulses of sound down to the ocean floor. The sound blasts can damage the ears of marine animals and cause serious injury. Scientists believe this noise may also be contributing to the altered behavior of whales.

Among those researching the effects of noise pollution is Michel Andre, a bioacoustics researcher in Spain who is recording ocean sounds using instruments called hydrophones. His project, LIDO (Listening to the Deep Ocean Environment), collects data at 22 different locations. Back in the lab, computers identify the sounds of human activities as well as 26 species of whales and dolphins. The analysis aims to determine the effects that underwater noise is having on these animals. Andre hopes his project will find ways to protect marine animals from the dangers of ocean noise.

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Noise pollution can cause health problems for people and wildlife, both on land and in the sea. From traffic noise to rock concerts, loud or inescapable sounds can cause hearing loss, stress, and high blood pressure. Noise from ships and human activities in the ocean is harmful to whales and dolphins that depend on echolocation to survive.