US absorbed carbon dioxide despite drought

In the US, spring 2012 was the warmest on record. The subsequent summer was dryer and hotter than any summer since the 1930s, a period that became known in the history books as the 'Dust Bowl'. In 2012, drought and heat afflicted almost the entire contiguous United States.

Climate researchers suspected that this summer drought four years ago could turn the contiguous United States into a carbon source, as was the case in Europe during the hot summer of 2003. During a normal year, ecosystems take up more carbon from the air than they release. They therefore act as a carbon sink - an effect that plays an important role for the world's climate.
This is because plants take up carbon dioxide (CO2) for growth during photosynthesis and then store it in the form of biomass and in the soil. Through this mechanism, ecosystems compensate for a third of the anthropogenic CO2 emissions.
A team of researchers from the US, Australia, the Netherlands and ETH Zurich have now shown that the contiguous United States remained a carbon sink in 2012, despite the drought. The study has just been published in the journal PNAS.


Read more at: http://phys.org/news/2016-04-absorbed-carbon-dioxide-drought.html#jCp