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Authors: John Benner, David Bethel,  Dana Desonie, Craig Freudenrich, Corliss Karasov, Mary Lusk, Erik Ong, Kurt Rosenkrantz, Julie Sandeen

Copyright: CC-SA

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High School Earth Science - Wikibooks, open books for an open world

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The material is not current as CK-12 now has a "no commercial use" license that is incompatible with Wikibooks. This work is licensed under the Creative Commons Attribution-Share Alike 3.0 United States License and was adapted from CK-12.

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Copyright: Crash Course 2018

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Earth Science: Crash Course History of Science #20

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Copyright: CC BY

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Founded in 2002 by Nobel Laureate Carl Wieman, the PhET Interactive Simulations project at the University of Colorado Boulder creates free interactive math and science simulations. PhET sims are based on extensive education research and engage students through an intuitive, game-like environment where students learn through exploration and discovery.

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Copyright: CC BY-NC

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Lesson Objectives

Define and describe Earth science as a general field with many branches.

Identify the field of geology as a branch of Earth science dealing with the solid Earth.

Describe oceanography as a branch of Earth science that has several subdivisions that deal with the various aspects of the ocean.

Define meteorology as a branch of Earth science that deals with the atmosphere.

Understand that astronomy is an extension of Earth science that examines other parts of the solar system and universe.

List some of the other branches of Earth science, and how they relate to the study of the Earth.

Introduction

Earth science is made of many branches of knowledge concerning all aspects of the Earth system. The main branches are geology, meteorology, climatology, oceanography, and environmental science. Astronomy uses principles understood from Earth to learn about the solar system, galaxy, and universe.

Overview of Earth Science

Only recently have humans begun to understand the complexity of our planet Earth. We have only known for a few hundred years that Earth is just a tiny part of an enormous galaxy, which in turn is a tiny part of an even greater universe.

Earth science deals with any and all aspects of the Earth: its lands, interior, atmosphere, and oceans. In all its wonder, Earth scientists seek to understand the beautiful sphere on which we live, shown in Figure below.

Earth as seen from Apollo 17.

Earth is a very large, complex system or set of systems, so most Earth scientists specialize in studying one aspect of the planet. Since all of the branches of Earth science are connected, these researchers work together to answer complicated questions. The major branches of Earth science are described below.

Geology

Geology is the study of the Earth's solid material and structures and the processes that create them. Some ideas geologists might consider include how rocks and landforms are created or the composition of rocks, minerals, or various landforms. Geologists consider how natural processes create and destroy materials on Earth, and how humans can use Earth materials as resources, among other topics.

Geology has many branches, only a few of which are described in Figure below. As you learn about each branch of geology, think of an interesting question that you might like to try to answer.

(a) Mineralogists study the composition and structure of minerals and may look for valuable minerals. (b) Planetary geologists study the geology of other planets. Lunar geologists study the Moon. (c) Seismologists study earthquakes and the geologic processes that create them. They monitor earthquakes worldwide to protect people and property. (d) Scientists interested in fossils are paleontologists.

Oceanography

The study of water and its movements, distribution and quality is hydrology. Oceanography is more than just the hydrology of the oceans. Oceanography is the study of everything in the ocean environment, which covers about 70% of the Earth's surface ( Figure below). Recent technology has allowed people and probes to venture to the deepest parts of the ocean, but still much of the ocean remains unexplored.

Physical oceanographers study the movements of ocean water such as currents, waves, and tides.

Marine geologists learn about the rocks and geologic processes of the ocean basins. An animation of underwater high-resolution sonar can be found here: http://oceanexplorer.noaa.gov/explorations/02fire/logs/jul06/media/abefly.html. Marine biologists study life in the oceans.

Climatology and Meteorology

Meteorology includes the study of weather patterns, clouds, hurricanes, and tornadoes. Using modern technology such as radars and satellites, meteorologists are getting more accurate at forecasting the weather all the time ( Figure below).

Meteorologists forecast major storms to save lives and property.

Climatologists study the whole atmosphere, taking a long-range view. Climatologists can help us better understand how and why climate changes ( Figure below).

Carbon dioxide released into the atmosphere is causing the global climate to change.

Environmental Science

Environmental scientists study the effects people have on their environment, including the landscape, atmosphere, water, and living things ( Figure below).

Every action people take has some effect on Earth's environment.

Astronomy

Astronomers are interested in outer space and the physical bodies beyond the Earth. They use telescopes to see things far beyond what the human eye can see. Astronomers help to design spacecraft that travel into space and send back information about faraway places or satellites ( Figure below).

The Hubble Space Telescope.

Lesson Summary

The study of Earth science includes many different fields, including geology, meteorology, oceanography, and astronomy.

Each type of Earth scientist investigates the processes and materials of the Earth and beyond as a system.

Review Questions

1. What are three major branches of Earth science?

2. What branch of science deals with stars and galaxies beyond the Earth?

3. List some important functions of Earth scientists.

4. What is the focus of a meteorologist?

5. An astronomer has discovered a new planet. On the planet, she sees what appears to be a lava flow. With what type of scientist might she consult to help her figure it out?

6. An ecologist notices that an important coral reef is dying off. He believes that it has to do with some pollution from a local electric plant. What type of scientist might help him analyze the water for contamination?

7. Design an experiment that you could conduct in any branch of Earth science. Identify the independent variable and dependent variable. What safety precautions would you have to take?

Further Reading / Supplemental Links

Points to Consider

Why is Earth science important?

Which branch of Earth science would you most like to explore?

What is the biggest problem that humans face today? Which Earth scientists may help us to solve the problem?

How do the other branches of science impact Earth science?

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Define and describe Earth science as a general field with many branches. Identify the field of geology as a branch of Earth science dealing with the solid Earth. Describe oceanography as a branch of Earth science that has several subdivisions that deal with the various aspects of the ocean.

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An introduction to Deep Time, the Geological Timescale and dating the Earth's past

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Copyright: CC BY

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Australia's climate is changing. Observed changes over the 20th century include increases in global average air and ocean temperature, rising global sea levels, long-term sustained widespread reduction of snow and ice cover, and changes in atmospheric and ocean circulation and regional weather patterns, which influence seasonal rainfall conditions. ​

These changes are caused by extra heat in the climate system due to the addition of greenhouse gases to the atmosphere. The additional greenhouse gases are primarily due to human activities such as the burning of fossil fuels (coal, oil, and natural gas), agriculture, and land clearing. These activities increase the amount of heat-trapping greenhouse gases in the atmosphere. The pattern of observed changes in the climate system is consistent with an increased greenhouse effect. Other climatic influences like volcanoes, the sun and natural variability cannot explain the timing and extent of the observed changes.

The evidence of climate change is supported by extensive scientific research performed and reported across the world. Past and present climate information is collected from observations and measurements of our environment, including trapped air in ice from thousands of years ago. Climate models are used to understand the causes of climate change and to project changes into the future.

Many of the impacts of climate change pose risks to human and natural systems, through more frequent and severe heat waves, coastal inundation due to sea level rise, disruptions to rainfall patterns and other effects. Analyses of a range of climate scenarios indicate the most severe risks of climate change can largely be mitigated if greenhouse gas emissions are reduced to the point they are no longer accumulating in the atmosphere.

Greenhouse gas effect

The greenhouse effect is a natural process that warms the Earth's surface. When the Sun's energy reaches the Earth's atmosphere, some of it is reflected back to space and some is absorbed and re-radiated by greenhouse gases.

Greenhouse gases include carbon dioxide, methane, nitrous oxide, ozone and some artificial chemicals such as chlorofluorocarbons (CFCs).

The absorbed energy warms the atmosphere and the surface of the Earth. This process maintains the Earth's temperature at around 33 degrees Celsius warmer than it would otherwise be, allowing life on Earth to exist.

Increased greenhouse effect

The problem we now face is that human activities - particularly burning fossil fuels (coal, oil and natural gas), agriculture and land clearing - are increasing the concentrations of greenhouse gases. This is increasing the greenhouse effect, which is contributing to warming of the Earth.

Greenhouse effect

Step 1: Solar radiation reaches the Earth's atmosphere - some of this is reflected back into space.

Step 2: The rest of the sun's energy is absorbed by the land and the oceans, heating the Earth.

Step 3: Heat radiates from Earth towards space.

Step 4: Some of this radiative heat is trapped by greenhouse gases in the atmosphere, keeping the Earth warm enough to sustain life.

Step 5: Human activities such as burning fossil fuels, agriculture and land clearing are increasing the amount of greenhouse gases released into the atmosphere.

Step 6: This is trapping extra heat, and causing the Earth's temperature to rise, along with other effects like ocean acidification noted in the figure below.

Observed changes

Alternate text for "There are multiple lines of evidence that show the climate system is changing"

There are multiple lines of evidence that show the climate system is changing. These include:

record high surface air temperatures

increased average number of hot days per year

decreased average number of cold days per year

increasing intensity and frequency of extreme events (e.g. fires, floods)

changing rainfall patterns

increasing sea surface temperatures

rising sea levels

increasing ocean heat content

increasing ocean acidification

changing Southern Ocean currents

melting ice caps and glaciers

decreasing Arctic sea ice

Australia is already experiencing the impacts of a changing climate, particularly changes associated with increases in temperature, frequency and intensity of heatwaves, hazardous fire weather and drought conditions. Climate observations and future projections show that these changes from the historical climate are ongoing and long-term, and that they cannot be explained by natural variability (though they do interact with underlying natural variability).

Australia's changing climate

Air temperatures have increased globally by around 1.2 degrees Celsius since the late 1800s. This is when modern meteorological record keeping became widespread and reliable enough to produce global datasets. Most of the warming from 1880 to present has occurred since the 1970s. The observed increase in temperatures has occurred across the globe, with rising temperatures recorded on all continents and in the ocean. 2016 and 2020 are tied for the world's warmest year on record, and years 2015 and 2017 were the equal second warmest years on record globally.

Australia's weather and climate are changing in response to a warming global climate. Australia has warmed on average by 1.44 ± 0.24 °C since 1910, with most warming occurring since 1950 and every decade since then being warmer than the ones before.

Australia's warmest year on record was 2019, with an average temperature 1.52°C above the 1961-1990 average. The seven years from 2013 to 2019 all rank in the warmest years on record. This long-term warming trend means that most years are now warmer than almost any observed during the 20th century. When relatively cooler years do occur, it is because natural drivers that typically cool Australia's climate, such as La Niña, act to partially offset the background warming trend (Figure 1).

Ocean warming and sea level rise

One of the strongest indicators of climate change is the amount of heat stored in the world's oceans. The heat content of oceans has increased during recent decades and accounts for more than 90 per cent of the total heat trapped by added greenhouse gases and accumulated by the land, air and ocean since the 1970s. Ocean warming is continuing, especially in the top several hundred metres of the ocean. In the Australian region, the average sea surface temperature for each decade since 1900 has been warmer than the previous decade (Figure 2).

Average sea surface temperature in the Australian region has warmed by more than 1°C since 1900, with eight of the ten warmest years on record occurring since 2010. The warmest year on record was 2016, associated with one of the strongest negative Indian Ocean Dipole events on record.

The greatest ocean warming in the Australian region since 1970 has occurred around southeastern Australia and Tasmania. The East Australian Current now extends farther south than in earlier decades, creating an area in the Tasman Sea where the warming rate is now twice the global average. There has also been warming across large areas of the Indian Ocean region to the southwest of Australia. Warming of the ocean has contributed to longer and more frequent marine heatwaves.

The increasing frequency of marine heatwaves around Australia in recent years has caused significant impacts on marine ecosystem health, marine habitats and species. These impacts include depleting kelp forests and sea grasses, a poleward shift in some marine species, and increased occurrence of disease. Recent marine heatwaves are the primary cause of mass coral bleaching and widespread damage to coral reefs around Australia, including the Great Barrier and Ningaloo reefs. Other pressures such as tropical cyclones, nutrient runoff and disease also affect the health of some areas of the Great Barrier Reef.

There is clear evidence that sea levels have risen as a result of climate change, based on observations from tide gauges, measurements of our past climate and satellite measurements.

Global mean sea level rise is accelerating. Tide gauge and satellite altimetry observations show that the rate of global mean sea level rise increased from 1.5 ± 0.2 cm per decade (1901-2000) to 3.5 ± 0.4 cm per decade (1993-2019). The dominant cause of global mean sea level rise since 1970 is anthropogenic climate change. Australia, like other nations, is already experiencing sea level rise. Sea level varies from year to year and from place to place, partly due to the natural variability of the climate system from the effect of climate drivers such as El Niño and La Niña. Based on satellite altimetry observations since 1993, the rates of sea level rise to the north and southeast of Australia have been significantly higher than the global average, whereas rates of sea level rise along the other coasts of the continent have been closer to the global average. (Figure 3).

Ocean currents are also changing, particularly in the Southern Ocean. Studies have shown that the deepest ocean water in the Antarctic, which is normally the coldest water, has warmed and become less saline since the 1980s. The world's deep ocean currents play a critical role in transporting heat around the planet, thus regulating the climate. Warming of these currents alters their ability to perform this function.

Another serious impact of the increasing concentration of atmospheric carbon dioxide is ocean acidification. Around a quarter of the carbon dioxide produced by humans is absorbed by the oceans. As the carbon dioxide dissolves in sea water it forms carbonic acid, making the ocean more acidic. There are early indications that some marine organisms are already being affected by ocean acidification.

Many marine species that have low mobility or rely on specific habitats or narrow temperature ranges for survival, such as marine plants, corals, and other invertebrates, may not be able to move to new or more suitable habitats. If they cannot move, then as the oceans become warmer and more acidic it becomes harder for these organisms to evolve quickly enough for populations to remain viable. For those marine organisms that form shells or bodies of calcium carbonate minerals, (for example, molluscs and corals), it also becomes more difficult for them to capture and absorb the minerals they need from the sea water to maintain and grow their bodies.

Initially these changes are likely to have the greatest impacts on marine environments such as coral reefs as well as the Arctic and Antarctic ecosystems. Eventually almost all aquatic ecosystems will be affected by increasing levels of ocean warming and acidification if greenhouse gas emissions are not curbed and reversed.

Extreme weather events

Extreme weather and climate events have serious impacts on our economy, society and environment. Extreme weather events include heatwaves, bushfires, tropical cyclones, cold snaps, extreme rainfall including flash flooding, and droughts.

There is increasing evidence that the frequency and intensity of many types of extreme weather events are changing. Extreme hot days in Australia are getting hotter, with the frequency of very hot (greater than 40°C) daytime temperatures increasing since the 1990s (Figure 4).

In addition, there has been an increase in extreme fire weather and fire season length across large parts of Australia since the 1950s, with a rapid increase in the late 1990s to early 2000s at many locations in south-eastern Australia.

Individual extreme events occur as a result of a number of contributing climatic factors. A growing body of research provides estimates of the relative contribution of natural variability and anthropogenic (human-caused) climate change to individual extreme events. For example, a study by the ARC Centre of Excellence for Climate System Science analysed the record heat and record low rainfall in winter 2017. It found that conditions were 60 times more likely to have occurred because of climate change than they would have otherwise.

Understanding the influences on such events helps us to better understand how and why extreme events are changing and allows us to plan for the future impacts of these events in Australia.

Rainfall patterns

Rainfall patterns are changing around the world. Research shows the global water cycle is intensifying with a warming climate, which means wet areas are likely to get wetter and dry regions are likely to be drier in response to climate change.

Australian rainfall is highly variable. Average annual rainfall has slightly increased since 1900, with a large increase in northwest Australia since 1970. Trends in rainfall over recent decades include:

increased spring and summer monsoonal rainfall across the north

higher than normal rainfall across the centre

decreased late autumn and winter rainfall across the south.

A climate change signal has been identified in the observed long-term reduction of cool season rainfall in southern Australia, with significant declines since the 1970s in southwest Western Australia (17 per cent), and since the mid-1990s in south-eastern Australia. South-eastern Australia experienced the most persistent rainfall deficit between 1997 and 2009 since records began at the start of the 20th Century.

More information on general climate impacts across Australia is provided in the State of the Climate 2020 report or on the website Climate Change in Australia.

Climate resources

Climate change science provides the information needed to understand and plan for climate change impacts, thereby increasing community resilience and reducing the cost of climate change impacts to society. Australian scientists are at the forefront of global efforts to understand the science behind climate change. Australia has a unique interest in and responsibility for leading climate change research in the southern hemisphere.

Climate change science is provided to the Australian Government by agencies such as the CSIRO and the Bureau of Meteorology, state and territory government agencies, as well as university research groups and cooperative research centres. Climate change science from these sources is reliable and quality assured because it goes through a stringent process of peer-review during which other scientists check the results of the research.

Peer-reviewed research

The peer-review process involves scientists evaluating the quality of other scientists' work. It provides a mechanism to quality control scientific discourse and peer-reviewed papers, by ensuring that the work is rigorous, coherent, uses past research and adds to what we already know. Climate change science that has been peer-reviewed therefore provides a reliable and quality assured source of information.

To publish in most scientific journals, conference proceedings, and to apply for grants, scientists have to go through a peer review process. The peer review process is usually a 'blind' review. This means that the authors do not know the identity of the reviewers. This process is designed to ensure evaluation is independent.

The Intergovernmental Panel on Climate Change (IPCC) assesses the peer-reviewed literature on climate change every five to six years, and publishes its findings in Assessment Reports. The IPCC reports are themselves subject to an intense peer-review process involving hundreds of scientific experts and government reviewers. This unprecedented level of peer and government review makes this compendium of climate change science one of the most scrutinised documents in the history of science.

Read more

See more

Temperature

Oceans

Extremes

Rainfall

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Australia's climate is changing. Observed changes over the 20th century include increases in global average air and ocean temperature, rising global sea levels, long-term sustained widespread reduction of snow and ice cover, and changes in atmospheric and ocean circulation and regional weather patterns, which influence seasonal rainfall conditions.​

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Copyright: public domain

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Clarification Statement: Emphasis is on the energy transfer mechanisms that allow energy from nuclear fusion in the sun's core to reach Earth. Examples of evidence for the model include observations of the masses and lifetimes of other stars, as well as the ways that the sun's radiation varies due to sudden solar flares ("space weather"), the 11-year sunspot cycle, and non-cyclic variations over centuries.

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The Structure and Composition of the Earth

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The Structure and Composition of the Earth

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The Composition and Structure of Earth | Physical Geography

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Core, mantle, and crust are divisions based on composition. The crust makes up less than 1 percent of Earth by mass, consisting of oceanic crust and continental crust is often more felsic rock. The mantle is hot and represents about 68 percent of Earth’s mass. Finally, the core is mostly iron metal.…

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Copyright: CC BY-NC-SA

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For people with an interest in the earth sciences. An introduction to the earth sciences in easy to read english. Most resources on-site. Since 1996