Image courtesy of Al- Fassam
A study carried out by the National Oceanic and Atmospheric Administration (NOAA) has reaffirmed a link between the droughts that have plagued many parts of the U.S. and climate change - though not the one you may have initially pegged. While many recent studies have sought to draw a link between the warming climate and the increased aridity of certain regions in the country - suggesting that climate change may be to blame for some of the record drought seasons we've witnessed - this study has posited that droughts may in fact be aggravating climate change by hindering the uptake of millions of tons of carbon dioxide.
Using NOAA's new atmospheric monitoring and modeling system, CarbonTracker, lead scientist Andy Jacobson of the University of Colorado found that the amount of carbon dioxide absorbed by soil and vegetation plunged from an average of 650m metric tons a year to 330m metric tons. The culprit, according to Jacobson and his colleagues, is the drought that swept across close to 45% of North America in 2002."Everyone here has been surprised about how big an impact the drought had on the variability of the carbon cycle. This is the first time we've been able to get a picture of year-to-year variability and also spatial variability within the continent," said Jacobson, who equated the extra amount of carbon dioxide emissions remaining in the atmosphere to the annual emissions of more than 200 million cars.
Droughts are believed to affect climate change by impacting carbon sinks - forests, crops and soil, to name a few - and by disrupting their uptake of carbon dioxide through changes to rainfall patterns, soil moisture and average temperatures. This, of course, makes perfect sense: because of the droughts, you get large die-offs in the number of crops and other plants that normally take up a significant chunk of carbon dioxide to conduct photosynthesis.
John Miller, a co-author on the study, noted the presence of a cyclical relationship between the climate and the carbon cycle. "We're pretty confident that if you suddenly get a lot of drought, you get more plant decomposition and less absorption of carbon. As a result, carbon dioxide is higher in the atmosphere, and the more carbon in the atmosphere the more warming. So you have a positive, vicious cycle building up."
Talk about a nasty double whammy: it sure seems now as though the crippling water shortages many regions in the South and Southeast have faced could become just one of a series of problems.
Via ::Daily Camera: NOAA: Drought hinders CO2 uptake (newspaper)