Unit 2: The Carbon Cycle

Image Source: IPCC, 2013: Climate Change 2013

What is the Carbon Cycle & CO2?

To understand climate, change you need to understand what produces CO2 and how CO2 effects atmospheric temperatures.  The carbon cycle is crucial in understanding the science of climate change.  This section will go more in-depth than others in this guide.  The reasons for this include being fluent in the science of carbon, to educate our students, and for our students to be able to differentiate fact from fiction when it comes to climate change.  One just needs to look at social media posts to see arguments that dismiss climate change using reasoning with little basis in science.  Now it’s time to dig into the science!  This section will look at:

 1. Sources of  Carbon dioxide

2. The Carbon cycle

Here is my super quick take on carbon and it's roll in climate change.  Humans burn things that contain carbon (like oil and trees). The carbon is released into the atmosphere where it acts to redirect some of the heat given off by the Earth.  Some of the heat that is headed into space but carbon in the form of C02 back down to the Earth.  This redirecting of heat is called the Green House Effect.  The heat redirected to the Earth's surface by carbon released by human activity is what's causing global warming.  The effects of global warming are widespread from sea level rises, acidification of the ocean, unusually heavy rainstorms, an increase in desertification, crop losses, and on and on (More on climate change effects on unit 6).  In the U.S. we are just beginning to see these problems, but if CO2 concentrations continue to increase and therefore temperatures increase, then the effects will be devastating for humans (our students will be directly effected, and catastrophic for some plant and animal life that can't adjust to how quickly the world is warming. 


Sources of Carbon Dioxide

From Climate.gov (The U.S. government site on climate) “There are natural sources of carbon dioxide, such as decomposing biomass, venting volcanoes, naturally occurring wildfires, human and animal respiration, etc. Over geological time spans before the industrial revolution, these natural sources of carbon dioxide were in balance with natural "sinks"—such as the ocean, phytoplankton, and plants on land that absorb carbon dioxide. The only new process on Earth that has been identified that can account for the significant tipping of Earth's carbon balance is humans burning ever increasing amounts of fossil fuels together with other large-scale activities like deforestation, biomass burning, and cement production. Since the industrial revolution, human activities have increased the abundance of carbon dioxide in the lower atmosphere by about 40%”.  https://www.climate.gov/news-features/climate-qa/doesnt-carbon-dioxide-atmosphere-come-natural-sources

The Basics of Earths atmosphere, Green House Gasses, The Carbon Cycle.  Source: Earth System Research Laboratories. https://www.esrl.noaa.gov/gmd/education/carbon_toolkit/basics.html

A more advanced look at the Carbon Cycle. From NOAA (National Oceanic and Atmospheric Administration)on




The Carbon Cycle

Source: (Wheeling Jesuit University / Center for Educational Technologies®.) While this website is no longer funded/updated, it still has accurate and useful information.  http://ete.cet.edu/gcc/?/globaltemp_carbon_cycle/


Why an Increase in CO2 Causes the Earth to Warm

From Arcadia.com (A clean energy company) they do an excellent job of explaining how man made CO2 causes the Earth to warm.  Here is a link to their discussion..”  https://www.arcadia.com/energy-101/environmental-impact/greenhouse-gas-emissions-natural-vs-man-made/


More information on the carbon cycle:

Source: NASA Exploring the Environment “The carbon cycle sources and sinks” http://ete.cet.edu/gcc/?/globaltemp_carbon_cycle/


Source: NASA “Climate and Earth’s Energy Budget”  https://earthobservatory.nasa.gov/features/EnergyBalance


Source: NIWA, the National Institute of Water and Atmospheric Research “What is a Carbon sink?”  https://niwa.co.nz/atmosphere/faq/what-is-a-carbon-sink


Source:  Berkley Lab, Nov 10, 2011 Carbon Cycle 2.0 talk Donald DePaoloAssociate Lab Director for Energy and Environmental Sciences, LBNL.  This is a one-hour video (fairly technical) PowerPoint presentation on Carbon and the history of the Earth and how human increases in CO2 is unprecedented in geologic history.  To summarize,  the presentations states that “The root cause of climate change is what could be called ‘carbon cycle change.’ To change global climate, the amount of CO2 in the atmosphere needs to change, which in turn requires a change in the way carbon is moved around among the various forms and places it exists in and on the Earth. Today, 98 to 99% of the net movement of carbon out of geologic reservoirs into the atmosphere is due to human activities. Whether you think this is a problem or not, it is nevertheless a fact that we are currently doing something that is unprecedented in Earth history”.  https://www.youtube.com/watch?v=CCYovuVKnxM


Sources of manmade CO2, from the Archived EPA (United States Environmental Protection Agency) website.  The Trump administration had most climate change information scrubbed from the EPA website.  The links below are archived versions of the EPA site before the climate change information was removed.


This site would be a great assignment for students to research and present the different sectors where human made CO2 is produced, and find ways to reduce carbon emissions.

Overview: https://19january2017snapshot.epa.gov/ghgemissions/sources-greenhouse-gas-emissions_.html#overview

Electricity: https://19january2017snapshot.epa.gov/ghgemissions/sources-greenhouse-gas-emissions_.html#electricity

Transportation: https://19january2017snapshot.epa.gov/ghgemissions/sources-greenhouse-gas-emissions_.html#transportation

Industry: https://19january2017snapshot.epa.gov/ghgemissions/sources-greenhouse-gas-emissions_.html#industry

Commercial/Residential: https://19january2017snapshot.epa.gov/ghgemissions/sources-greenhouse-gas-emissions_.html#commercial-and-residential

Agriculture: https://19january2017snapshot.epa.gov/ghgemissions/sources-greenhouse-gas-emissions_.html#agriculture

Land-use/Forestry: https://19january2017snapshot.epa.gov/ghgemissions/sources-greenhouse-gas-emissions_.html#land-use-and-forestry



Class activities on energy budget by Stanford Earth. Source: Standford University, CA:   https://earth.stanford.edu/climate-change-ed/curriculum/high/earths-energy-balance


This website does a good job creating many interactive activities.  Scource : Keslerscience.com a science teaching website run by a former middle school science teacher.  While it links to teacherspayteachers.com,  it will easily get you most of the way through this unit with your students.  https://www.keslerscience.com/carbon-cycle-lesson-plan-a-complete-science-lesson-using-the-5e-method-of-instruction/


Class activities on Carbon and Nitrogen cycles by Earthref.org.  Source Earth Refernce Data and Models, this site is run by the Scripts Institute of Oceanography.  https://earthref.org/SCC/lessons/2010/biogeochemistry/nitrogen-carbon-cycles/

Windows to the Universe has class activities concerning climate change (Adobie Flash Player is needed for some games).  It doesn't appear that this website has been updated recently, so some dates may be older.  The importance of older data is that CO2 concentrations and global temperatures have continued to rise! https://www.windows2universe.org/earth/climate/cli_games.html