NASA's OCO-2 will track our impact on airborne carbon [View all]

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June 26, 2014


By Alan Buis,
NASA's Jet Propulsion Laboratory



Every time we get in a car and drive, we burn gasoline, releasing carbon dioxide and other compounds into the air and disturbing Earth's climate. Our use of fossil fuels continues to increase exponentially, with more than half of all fossil fuels ever used by humans being consumed in the last 20 years.

In comparison with the amount of carbon that enters the atmosphere from natural sources, our fossil fuel emissions are modest. "Carbon dioxide generated by human activities amounts to only a few percent of the total yearly atmospheric uptake or loss of carbon dioxide from plant life and geochemical processes on land and in the ocean," said Gregg Marland, a professor in the Geology Department of Appalachian State University, Boone, North Carolina. "This may not seem like much, but humans have essentially tipped the balance."

Scientists are able to accurately measure the amount of carbon dioxide in the atmosphere, both today and in the past, and the impact of our activities is apparent in those measurements. Before the Industrial Revolution, there were about 280 molecules of carbon dioxide out of every million molecules in the atmosphere, that is, 280 parts per million. By 2014, the concentration had risen to about 400 parts per million.

Although we know the concentration of carbon dioxide, much about the processes that govern the gas's atmospheric concentration remains a mystery. We still do not know precisely where all of the carbon dioxide comes from and where it is being stored when it leaves the air. That information is crucial for understanding the impact of human activities on climate and for evaluating options for mitigating or adapting to climate change.


http://climate.nasa.gov/news/1109/