Daniel Cressey; cross-posted from The Great Beyond
The world’s carbon dioxide ‘sinks’ are not able to keep up with the amount of the greenhouse gas being produced, according to a paper published in Nature Geoscience.
Reviewing the recent literature Corinne Le Quéré, of the University of East Anglia, and colleagues report that between 1959 and 2008 43% of each year’s carbon dioxide emissions have remained in the atmosphere with the rest being absorbed by land and ocean sinks. However in the last 50 years they suggest that the fraction remaining in the atmosphere has increased from about 40% to 45%.
They also found that a 29% rise in carbon emissions between 2000 and 2008 can be attributed to a large extent to burning coal and the growth of the so-called ‘emerging economies’.
“The Earth’s carbon sinks are complex and there are some gaps in our understanding, particularly in our ability to link human-induced CO2 emissions to atmospheric CO2 concentrations on a year-to-year basis,” says Le Quéré (press release). “But, if we can reduce the uncertainty about the carbon sinks, our data could be used to verify the effectiveness of climate mitigations policies.”
Uncertainties in this area are huge. Another recent paper in Geophysical Research Letters suggested there has been no decline in the fraction absorbed by sinks.
The author of that paper, Wolfgang Knorr of the University of Bristol, says, “We are just at the very edge of being able to detect a trend in the airborne fraction. Our apparently conflicting results demonstrate what doing real science is like and just how difficult it is to accurately quantify such data.” (Press release.)
One thing the authors can apparently agree on: if global warming is going to be stopped emissions are going to have to be reduced drastically.