London, Nov 11 (Inditop.com) Our ecosystems and oceans have a much greater capacity to absorb carbon dioxide than had previously been thought.
Though carbon dioxide emissions have risen from about two billion tonnes in 1850 to 35 billion tonnes a year now, new data shows that the balance between the airborne and the absorbed fraction of carbon dioxide has stayed constant.
The results negate a significant body of research which shows that the capacity of ecosystems and oceans to absorb carbon dioxide should start to diminish as emissions increase, allowing greenhouse gas levels to skyrocket.
Wolfgang Knorr from the University of Bristol, who conducted the study, found that in fact the rising trend in the airborne fraction since 1850 has only been 0.7 to 1.4 percent per decade, which is essentially zero.
The strength of the new study is that it rests solely on measurements and statistical data, including historical records extracted from Antarctic ice, and does not rely on computations with complex climate models.
This work is extremely important for climate change policy, because emission targets to be negotiated at the UN Climate Change Conference in Copenhagen early next month have been based on projections that have a carbon free sink already factored in.
Some researchers have cautioned against this approach, pointing at evidence that suggests the sink has already started to decrease.
So is this good news for climate negotiations in Copenhagen? “Not necessarily,” says Knorr.
“Like all studies of this kind, there are uncertainties in the data, so rather than relying on nature to provide a free service, soaking up our waste carbon, we need to ascertain why the proportion being absorbed has not changed.”
These findings were published online in Geophysical Research Letters.
