Carbon detectives get help on the greenhouse gas trail
Stalking greenhouse gases may not seem like the stuff of detective novels, but the stakes are high when it comes to crafting effective policies to staunch global warming.
Anna Michalak, a University of Michigan professor, will share at a NASA symposium how combining on-the-ground data collecting with out-of-this-world – literally – technology can help scientists identify the locations and intensity of the world’s carbon releases and uptake.
“New tools for carbon detectives: Using atmospheric and satellite data to track carbon emissions and sequestration” will be part of a media briefing at 12:30 p.m. EDT June 24 at the National Academy of Sciences in Washington, DC.
The briefing is part of NASA's Earth Science Division symposium June 22-24 "NASA Earth System Science at 20: Accomplishments, Plans, and Challenges."
The event brings together scientists, managers, and policy makers to examine the 20-year history of the program and future directions in this emerging, multidisciplinary field
“Understanding carbon release and uptake is important, both for predictions of future climate change and for verification of possible future carbon management policies, such as treaties and cap and trade,” said Michalak, associate professor in the Department of Civil and Environmental Engineering and the Department of Atmospheric, Oceanic and Space Sciences.
Michalak has been developing a unique way to reconcile the data collected from atmospheric sampling locations sprinkled over the Earth and remote sensing observations of the Earth surface from NASA satellites. This approach, based on a technique called geostatistical inverse modeling, has allowed her research group to directly estimate carbon uptake and release from measurements of carbon dioxide at an unprecedented resolution for North America.
Scientists estimate that approximately 8 billion tons of carbon are pumped into the air every year, but only approximately half of that stays in the atmosphere. The rest comes to rest in the oceans, the earth, or is gobbled up by plants during photosynthesis. But then the data gets harder to come by and scientists have had to make some assumptions.
The problem: Michalak said the available atmospheric data takes such a big-picture approach that it is difficult to isolate carbon being emitted or taken up in specific regions, or even countries. Scientists are left with an understanding of carbon sources that isn't nimble enough to understand the variability, or to be confident about predicting the future.
Michalak has developed a robust way to use available data to understand this variability called "geostatistical inverse modeling." This method breaks the globe into small regions and examines how much CO2 must have been emitted in each region to achieve the concentrations measured at atmospheric sample points. This method also allows her and her collaborators to use information from other existing satellites that measure the Earth's surface to supplement the information from the atmospheric monitoring network. Eventually, this method aims to trace the carbon levels at each sample point to a particular source or sink on the surface.
The technique, Michalak says, is like figuring out where the cream was originally poured in a cup of half-stirred coffee.
"Winds and weather patterns mix CO2 in the atmosphere just like stirring mixes cream in a cup of coffee," she said. "As soon as you start stirring, you lose some information about where and when the cream was originally added to the cup. With careful measurements and models, however, much of this information can be recovered."
"One of our big questions is how carbon sources and sinks evolve," Michalak said. "This is all with an eye on prediction and management."
Michalak's work on the carbon cycle is funded by NASA and the U.S. Department of Energy. Michalak is a fellow with the U-M Michigan Memorial Phoenix Energy Institute, which develops, coordinates and promotes multidisciplinary energy research and education at
U-M.
To learn more about Michalak's research and areas of expertise visit http://www.energy.umich.edu/res/fac_09/fac_MichalakA09.html and http://www.ns.umich.edu/htdocs/public/experts/ExpDisplay.php?ExpID=1381