NASA has released a stunning visualization of how carbon dioxide flows around the world. In the simulation, plumes of the greenhouse gas gush into the atmosphere from major industrial centers, swirling from continent to continent on the winds of global weather systems. The simulation, which took 75 days to create on a supercomputer at NASA's Goddard Space Flight Center in Greenbelt, Maryland, depicts CO2 emissions from May 2005 to June 2007. Its superhigh-resolution mapping—64 times as great as the average climate model—dramatically illustrates two often neglected facts. The first is that CO2 emissions come almost exclusively from the Northern Hemisphere. The deep red plumes of the normally invisible gas flow from clusters in the United States, Europe, and Asia, eventually pooling over the Arctic region. The second is that massive amounts of carbon dioxide are absorbed seasonally by forests and other vegetation. As the model moves from late spring into summer, the rivers of red gas begin to fade away—drawn out of the atmosphere by photosynthesizing plants. Then, as the model slips into early winter and vegetation dies or goes dormant, CO2 flows back into the atmosphere. Humans dump about 36 billion metric tons of extra CO2 into the atmosphere each year by the burning of fossil fuels. In spring 2013, for the first time in history, atmospheric CO2 concentrations exceeded 400 parts per million. Scientists have warned that CO2 levels above 450 parts per million could result in dangerous disruptions of the climate; some think we may already have passed the danger threshold. To track CO2 emissions with greater precision, NASA launched a new satellite, the Orbiting Carbon Observatory-2 (OCO-2), on July 2. Researchers expect to release data from the satellite in early 2015. Besides helping scientists measure changes in CO2 emissions and flows, OCO-2 may also yield new insights into the behavior of carbon sinks such as forests and oceans that remove as much as half of all CO2 emissions from the atmosphere. Scientists are worried that such sinks may have reached their limits for absorbing carbon dioxide.

• published: 18 Nov 2014
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