Science News
from research organizations

Controversial new climate change data: Is Earth's capacity to absorb CO2 much greater than expected?

Date:
November 11, 2009
Source:
University of Bristol
Summary:
New data show that the balance between the airborne and the absorbed fraction of carbon dioxide has stayed approximately constant since 1850, despite emissions of CO2 having risen from about 2 billion tons a year in 1850 to 35 billion tons a year now. This suggests that terrestrial ecosystems and the oceans have a much greater capacity to absorb CO2 than had been previously expected.
Share:
       
FULL STORY

New data show that the balance between the airborne and the absorbed fraction of carbon dioxide has stayed approximately constant since 1850, despite emissions of carbon dioxide having risen from about 2 billion tons a year in 1850 to 35 billion tons a year now.
Credit: iStockphoto/Karl Dolenc

New data show that the balance between the airborne and the absorbed fraction of carbon dioxide has stayed approximately constant since 1850, despite emissions of carbon dioxide having risen from about 2 billion tons a year in 1850 to 35 billion tons a year now.

This suggests that terrestrial ecosystems and the oceans have a much greater capacity to absorb CO2 than had been previously expected.

The results run contrary to a significant body of recent research which expects that the capacity of terrestrial ecosystems and the oceans to absorb CO2 should start to diminish as CO2 emissions increase, letting greenhouse gas levels skyrocket. Dr Wolfgang Knorr at the University of Bristol found that in fact the trend in the airborne fraction since 1850 has only been 0.7 ± 1.4% per decade, which is essentially zero.

The strength of the new study, published online in Geophysical Research Letters, 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 United Nations Climate Change Conference in Copenhagen early in December have been based on projections that have a carbon free sink of 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."

Another result of the study is that emissions from deforestation might have been overestimated by between 18 and 75 per cent. This would agree with results published in early November in Nature Geoscience by a team led by Guido van der Werf from VU University Amsterdam. They re-visited deforestation data and concluded that emissions have been overestimated by at least a factor of two.


Story Source:

The above post is reprinted from materials provided by University of Bristol. Note: Materials may be edited for content and length.


Journal Reference:

  1. Knorr et al. Is the airborne fraction of anthropogenic CO2 emissions increasing? Geophysical Research Letters, 2009; 36 (21): L21710 DOI: 10.1029/2009GL040613

Cite This Page:

University of Bristol. "Controversial new climate change data: Is Earth's capacity to absorb CO2 much greater than expected?." ScienceDaily. ScienceDaily, 11 November 2009. <www.sciencedaily.com/releases/2009/11/091110141842.htm>.
University of Bristol. (2009, November 11). Controversial new climate change data: Is Earth's capacity to absorb CO2 much greater than expected?. ScienceDaily. Retrieved July 1, 2015 from www.sciencedaily.com/releases/2009/11/091110141842.htm
University of Bristol. "Controversial new climate change data: Is Earth's capacity to absorb CO2 much greater than expected?." ScienceDaily. www.sciencedaily.com/releases/2009/11/091110141842.htm (accessed July 1, 2015).

Share This Page: