According to our calculation, based on ballpark assumptions regarding fossil fuel consumption, human activity releases about 4.4 ppm of carbon dioxide into the atmosphere every year. However, actual measurements of atmospheric carbon dioxide show that atmospheric carbon dioxide concentrations are only increasing by between 1.5 and 1.9 ppm/year. This suggests that some of the carbon dioxide we emit is being removed from the atmosphere.

Question For Thought

What are some possible carbon sinks that could remove carbon dioxide from the atmosphere, resulting in the difference between calculated anthropogenic carbon dioxide emissions and the actual measured increase in atmospheric carbon dioxide concentration?