Measuring Climate Change

The Carbon Cycle

Carbon flows among land, sea, and the atmosphere. But human activities since the mid-eighteenth century have changed carbon flows in ways that have lasting implications for the climate. This graphic depicts changes to global carbon flows in the 1990s relative to the preindustrial state.3

Fossil fuel burning and cement production 6.4 GtC

Land use changes 1.6 GtC

Net increase to the atmosphere = 3.2 GtC

Land sinks 2.6 GtC

Ocean sinks 2.2 GtC

Annual change in billions of tons of carbon (GtC)

Temperature Conversion

Changes to global temperature caused by climate change are usually measured in degrees Celsius. One degree Celsius is equal to 1.8 degrees Fahrenheit— meaning that a 2-degree Celsius rise is 3.6 degrees Fahrenheit. Actual temperature readings in the different scales are easily compared when placed side by side.






- 96.8


- 93.2


- 89.6


- 86.0


- 82.4


- 78.8


- 75.2




- 68.0


- 64.4


- 60.8


- 57.2


- 53.6


- 50.0


- 46.4


- 42.8


- 39.2


- 35.6


r 32

Climate Change Reference Guide and Glossary

Carbon, Carbon Dioxide, and Carbon Dioxide Equivalents

Carbon, the basis of life on Earth, is at the center of the climate crisis. Carbon is found in solid, liquid, and gaseous form. CO2 is the most prevalent of human-generated greenhouse gases. CO2 is so dominant that all other greenhouse gases are evaluated in terms of their equivalency to CO2.



Carbon Dioxide

Carbon Dioxide Equivalent

Molecular One atom of carbon. makeup

One atom of carbon and two atoms of oxygen.

A measurement, not a chemical element, so no molecular formula.


CO2 or CO2

2eq 2e


Carbon cycles among land, sea, air, and biological systems and is the building block of many but not all greenhouse gases.

A gaseous form of carbon, CO2 is the breath people exhale, the fizz in soda—and part of the exhaust from burning fossil fuels. Most human carbon emissions are in the form of CO2.

A unit of measurement that allows the global warming contribution of greenhouse gases to be compared with each other, even if they have a different molecular makeup.

Calculation One ton of carbon = 3.67 tons of carbon dioxide.

Not typically converted to other units. Measured as emissions and as a concentration in the atmosphere.

Quantity of a greenhouse gas multiplied by its global warming potential.

Global Warming Potential of Selected Greenhouse Gases

Global warming potential (GWP) expresses a gas's heat-trapping power relative to carbon dioxide over a particular time period (thisTable uses the common 100-year frame). GWP allows observers to compare the contributions to climate change made by various greenhouse gases that have different warming effects and life spans. A methane molecule, for example, has 25 times the warming potential of a carbon dioxide molecule, and some gases are hundreds or thousands of times more powerful.4

Greenhouse Gas

Global Warming Potential

Carbon Dioxide Methane Nitrous Oxide Hydrofluorocarbons Perfluorocarbons Sulfur Hexafluoride

Climate Change Reference Guide and Glossary

Top 10 CO2-Emitting Nations,Total and Per Person, 2005

National emissions levels vary greatly. Among the top 10 emitters, the United States generates 12 times more CO2 than Italy does.The 10 leading emitters generate many more times the emissions of most developing countries, although emissions in those countries are rising rapidly and could soon overtake the annual emissions in industrial countries.The top 10 emitting nations also exhibit a broad range of emissions per person.Wealthy countries tend to emit more carbon dioxide per person than poor countries do.5

Top 10 CO2-Emitting Nations' Share of Global CO2 Emissions, 1950-2005

Over time, early industrializing nations typically have emitted more carbon dioxide to the atmosphere than nations that industrialized later.6

Climate Change Reference Guide and Glossary

Concentration of CO2 in Earth's Atmosphere, 1744-2007

Source: Neftal et al., Etheridge et al., NOAA

Atmospheric measurements J


1740 1770 1800 1830 I860 1890 1920 1950 1980 2010

Since the mid-eighteenth century fossil fuel use and cement production have released billions of tons of CO2 to the atmosphere. Carbon dioxide levels in the atmosphere before the Industrial Revolution were some 280 parts per million (ppm). By 2007, levels had reached 384 ppm—a 37-percent increase.7

Guide to Alternative Fuels

Guide to Alternative Fuels

Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.

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