Ross
5th February 2011, 21:32
Last year's drought (2010) in the Amazon raises concerns about the region's capacity to continue absorbing carbon dioxide, scientists say.
The 2005 drought had been termed a "one in a century" event. While 2010 was more extreme.
In drought years, the Amazon region changes from being a net absorber of carbon dioxide into a net emitter.
The 2010 drought saw the Amazon River at its lowest levels for half a century, with several tributaries completely dry and more than 20 municipalities declaring a state of emergency.
Both droughts were associated with unusually warm seas in the Atlantic Ocean off the Brazilian coast.
Its observation showed that whereas the 2005 drought covered an area of nearly two million sq km, in 2010 it stretched for three million sq km.
In an average year, the basin absorbs about 1.5 billion tonnes of CO2 from the atmosphere.
By contrast, the impact of the 2005 drought, spread over a number of years, was calculated as a release of five billion tonnes.
The figure for 2010 is about eight billion tonnes, as much as the annual emissions of China and Russia combined; but this, the researchers acknowledge, is a first estimate.
http://www.bbc.co.uk/news/science-environment-12356835
Ross.
The 2005 drought had been termed a "one in a century" event. While 2010 was more extreme.
In drought years, the Amazon region changes from being a net absorber of carbon dioxide into a net emitter.
The 2010 drought saw the Amazon River at its lowest levels for half a century, with several tributaries completely dry and more than 20 municipalities declaring a state of emergency.
Both droughts were associated with unusually warm seas in the Atlantic Ocean off the Brazilian coast.
Its observation showed that whereas the 2005 drought covered an area of nearly two million sq km, in 2010 it stretched for three million sq km.
In an average year, the basin absorbs about 1.5 billion tonnes of CO2 from the atmosphere.
By contrast, the impact of the 2005 drought, spread over a number of years, was calculated as a release of five billion tonnes.
The figure for 2010 is about eight billion tonnes, as much as the annual emissions of China and Russia combined; but this, the researchers acknowledge, is a first estimate.
http://www.bbc.co.uk/news/science-environment-12356835
Ross.