VIDEO: The carbon cycle describes the process in which carbon atoms continually travel from the atmosphere to the Earth and then back into the atmosphere. Human activities have a tremendous impact on this cycle. Burning fossil fuels, changing land use, and using limestone to make concrete all transfer massive quantities of carbon into the atmosphere. As a result, the amount of carbon dioxide in the atmosphere is rapidly rising — it is now greater than at any time in the last 3.6 million years. Transcript Show
 Blue CarbonBlue carbon is the term for carbon captured by the world's ocean and coastal ecosystems. Sea grasses, mangroves, salt marshes, and other systems along our coast are very efficient in storing CO2. These areas also absorb and store carbon at a much faster rate than other areas, such as forests, and can continue to do so for millions of years. The carbon found in coastal soil is often thousands of years old. When these systems are damaged or disrupted by human activity, an enormous amount of carbon is emitted back into the atmosphere, contributing to climate change. Carbon is the foundation of all life on Earth, required to form complex molecules like proteins and DNA. This element is also found in our atmosphere in the form of carbon dioxide (CO2). Carbon helps to regulate the Earth’s temperature, makes all life possible, is a key ingredient in the food that sustains us, and provides a major source of the energy to fuel our global economy. The carbon cycle describes the process in which carbon atoms continually travel from the atmosphere to the Earth and then back into the atmosphere. Since our planet and its atmosphere form a closed environment, the amount of carbon in this system does not change. Where the carbon is located — in the atmosphere or on Earth — is constantly in flux. On Earth, most carbon is stored in rocks and sediments, while the rest is located in the ocean, atmosphere, and in living organisms. These are the reservoirs, or sinks, through which carbon cycles. Carbon is released back into the atmosphere when organisms die, volcanoes erupt, fires blaze, fossil fuels are burned, and through a variety of other mechanisms. In the case of the ocean, carbon is continually exchanged between the ocean’s surface waters and the atmosphere, or is stored for long periods of time in the ocean depths. Humans play a major role in the carbon cycle through activities such as the burning of fossil fuels or land development. As a result, the amount of carbon dioxide in the atmosphere is rapidly rising; it is already considerably greater than at any time in the last 800,000 years. Video TranscriptWhat is the carbon cycle? Carbon is the chemical backbone of all life on Earth. All of the carbon we currently have on Earth is the same amount we have always had. When new life is formed, carbon forms key molecules like protein and DNA. It's also found in our atmosphere in the form of carbon dioxide or CO2. The carbon cycle is nature's way of reusing carbon atoms, which travel from the atmosphere into organisms in the Earth and then back into the atmosphere over and over again. Most carbon is stored in rocks and sediments, while the rest is stored in the ocean, atmosphere, and living organisms. These are the reservoirs, or sinks, through which carbon cycles. The ocean is a giant carbon sink that absorbs carbon. Marine organisms from marsh plants to fish, from seaweed to birds, also produce carbon through living and dying. Over millions of years, dead organisms can become fossil fuels. When humans burn these fuels for energy, vast amounts of carbon dioxide are released back into the atmosphere. This excess carbon dioxide changes our climate — increasing global temperatures, causing ocean acidification, and disrupting the planet’s ecosystems. BackgroundSince the Industrial Revolution began in the 1700s, people have added a substantial amount of greenhouse gases into the atmosphere by burning fossil fuels, cutting down forests, and conducting other activities (see the U.S. and Global Greenhouse Gas Emissions indicators). When greenhouse gases are emitted into the atmosphere, many remain there for long time periods ranging from a decade to many millennia. Over time, these gases are removed from the atmosphere by chemical reactions or by emissions sinks, such as the oceans and vegetation, which absorb greenhouse gases from the atmosphere. As a result of human activities, however, these gases are entering the atmosphere more quickly than they are being removed, and thus their concentrations are increasing. Carbon dioxide, methane, nitrous oxide, and certain manufactured gases called halogenated gases (gases that contain chlorine, fluorine, or bromine) become well mixed throughout the global atmosphere because of their relatively long lifetimes and because of transport by winds. Concentrations of these greenhouse gases are measured in parts per million (ppm), parts per billion (ppb), or parts per trillion (ppt) by volume. In other words, a concentration of 1 ppb for a given gas means there is one molecule of that gas in every 1 billion molecules of air. Some halogenated gases are considered major greenhouse gases due to their very high global warming potentials and long atmospheric lifetimes even if they only exist at a few ppt (see table). Ozone is also a greenhouse gas, but it differs from other greenhouse gases in several ways. The effects of ozone depend on its altitude, or where the gas is located vertically in the atmosphere. Most ozone naturally exists in the layer of the atmosphere called the stratosphere, which ranges from approximately 6 to 30 miles above the Earth’s surface. Ozone in the stratosphere has a slight net warming effect on the planet, but it is good for life on Earth because it absorbs harmful ultraviolet radiation from the sun, preventing it from reaching the Earth’s surface. In the troposphere—the layer of the atmosphere near ground level—ozone is an air pollutant that is harmful to breathe, a main ingredient of urban smog, and an important greenhouse gas that contributes to climate change (see the Climate Forcing indicator). Unlike the other major greenhouse gases, tropospheric ozone only lasts for days to weeks, so levels often vary by location and by season. Technical Documentation
References1. USGCRP (U.S. Global Change Research Program). 2017. Climate science special report: Fourth National Climate Assessment, volume I. Wuebbles, D.J., D.W. Fahey, K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock, eds. https://science2017.globalchange.gov. doi:10.7930/J0J964J6. 2. IPCC (Intergovernmental Panel on Climate Change). 2022. Climate change 2022: Mitigation of climate change. Working Group III contribution to the IPCC Sixth Assessment Report. Cambridge, United Kingdom: Cambridge University Press. . 3. USGCRP (U.S. Global Change Research Program). 2017. Climate science special report: Fourth National Climate Assessment, volume I. Wuebbles, D.J., D.W. Fahey, K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock, eds. https://science2017.globalchange.gov. doi:10.7930/J0J964J6. 4. USGCRP (U.S. Global Change Research Program). 2017. Climate science special report: Fourth National Climate Assessment, volume I. Wuebbles, D.J., D.W. Fahey, K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock, eds. https://science2017.globalchange.gov. doi:10.7930/J0J964J6. 5. [see full list provided below] 6. [see full list provided below] 7. [see full list provided below] 8. AGAGE (Advanced Global Atmospheric Gases Experiment). 2022. ALE/GAGE/AGAGE database. Updated June 14, 2022. Accessed July 2022. http://agage.eas.gatech.edu/data_archive/global_mean. 9. NOAA (National Oceanic and Atmospheric Administration). 2019. Halocarbons and Other Atmospheric Trace Species group (HATS). Updated October 2019. Accessed January 2021. https://gml.noaa.gov/aftp/data/hats/Total_Cl_Br. 10. Rigby, M. 2017 update to data originally published in: Arnold, T., C.M. Harth, J. Mühle, A.J. Manning, P.K. Salameh, J. Kim, D.J. Ivy, L.P. Steele, V.V. Petrenko, J.P. Severinghaus, D. Baggenstos, and R.F. Weiss. 2013. Nitrogen trifluoride global emissions estimated from updated atmospheric measurements. P. Natl. Acad. Sci. USA 110(6):2029–2034. Data updated December 2017. 11. NASA (National Aeronautics and Space Administration). 2013. Data—TOMS/SBUV TOR data products. Accessed November 2013. https://science-data.larc.nasa.gov/TOR/data.html. 12. NASA (National Aeronautics and Space Administration). 2021. Tropospheric ozone data from AURA OMI/MLS. Accessed May 2022. https://acdb-ext.gsfc.nasa.gov/Data_services/cloud_slice/new_data.html. 13.NASA (National Aeronautics and Space Administration). 2022. SBUV merged ozone data set (MOD). Version 8.7. Updated May 21, 2022. Accessed May 2022. https://acdb-ext.gsfc.nasa.gov/Data_services/merged/index.html. 14. IPCC (Intergovernmental Panel on Climate Change). 2013. Climate change 2013: The physical science basis. Working Group I contribution to the IPCC Fifth Assessment Report. Cambridge, United Kingdom: Cambridge University Press. www.ipcc.ch/report/ar5/wg1. Atmospheric Concentrations of Greenhouse Gases: Citations for Figures 1, 2, and 3Figure 1Antarctic Ice Cores: approximately 805,669 BCE to 2001 CE Mauna Loa, Hawaii: 1959 CE to 2021 CE Barrow, Alaska: 1974 CE to 2021 CE Cape Grim, Australia: 1977 CE to 2021 CE Shetland Islands, Scotland: 1993 CE to 2002 CE Lampedusa Island, Italy: 1993 CE to 2000 CE EPICA Dome C, Antarctica: approximately 797,446 BCE to 1937 CELoulergue, L., A. Schilt, R. Spahni, V. Masson-Delmotte, T. Blunier, B. Lemieux, J.-M. Barnola, D. Raynaud, T.F. Stocker, and J. Chappellaz. 2008. Orbital and millennial-scale features of atmospheric CH4 over the past 800,000 years. Nature 453:383–386. www.ncei.noaa.gov/access/paleo-search/study/6093. Law Dome, Antarctica: approximately 1008 CE to 1980 CE Cape Grim, Australia: 1985 CE to 2021 CE Mauna Loa, Hawaii: 1984 CE to 2020 CE Shetland Islands, Scotland: 1993 CE to 2001 CE EPICA Dome C, Antarctica: approximately 796,475 BCE to 1937 CE Antarctica: approximately 1903 CE to 1976 CE Cape Grim, Australia: 1979 CE to 2021 CE South Pole, Antarctica: 1998 CE to 2021 CE What causes increase in carbon dioxide?Human Activity Is the Cause of Increased Greenhouse Gas Concentrations. Over the last century, burning of fossil fuels like coal and oil has increased the concentration of atmospheric carbon dioxide (CO2). This increase happens because the coal or oil burning process combines carbon with oxygen in the air to make CO2.
What are 3 things that are causing carbon dioxide levels to increase?Burning fossil fuels, releasing chemicals into the atmosphere, reducing the amount of forest cover, and the rapid expansion of farming, development, and industrial activities are releasing carbon dioxide into the atmosphere and changing the balance of the climate system.
Which of the following best explains why the amount of carbon dioxide is higher during the winter than in summer?On the other hand, during the Northern Hemisphere's winter, atmospheric carbon dioxide levels rise because decomposing plant matter in the Northern Hemisphere releases carbon dioxide, and there is not enough photosynthesizing plant life in the Southern Hemisphere (which is experiencing summer during the Northern ...
Why is the amount of carbon dioxide in the atmosphere increasing quizlet?Due to the burning of large amounts of fossil fuels (coal, oil, natural gas), the amount of greenhouse gases in the atmosphere has dramatically increased (burning fossil fuels releases Carbon Dioxide).
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Which of the following choices best explains why is there an increase in carbon dioxide?
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