Scientific debate sparked over carbon sink data

November 18, 2009

(PhysOrg.com) -- According to research published this week in Nature Geoscience, emissions of carbon dioxide continue to outstrip the ability of the world’s natural ‘sinks’ to absorb carbon.

The new report follows another study published only ten days earlier by Dr Wolfgang Knorr in Geophysical Research Letters, which concludes that a decline in the capacity of terrestrial ecosystems and the oceans to absorb CO2 cannot be detected within the available data.

Both studies involved researchers from the University of Bristol’s QUEST programme on climate change and modelling.

About two thirds of the carbon dioxide we emit into the atmosphere is taken up by natural sinks on land and in the . An important issue for in Copenhagen next month will be whether or not the ability of these natural sinks to absorb emissions is declining.

The Nature Geoscience team, under the umbrella of the Global Carbon Project, found that over the past 50 years the average fraction of global CO2 emissions that remained in the atmosphere each year has likely increased from 40 per cent to 45 per cent, suggesting a decrease in the efficiency of the natural sinks such as the oceans and terrestrial ecosystems. The team brings evidence that the sinks are responding to climate change and variability.

Dr Wolfgang Knorr’s study on the other hand found no increase in the airborne fraction during the past 50 years and that the trend was in fact negative at -0.2 ± 1.7% per decade, which is essentially zero. He therefore concluded that the capacity of terrestrial ecosystems and the oceans to absorb CO2 has not diminished.

Both studies are based on data and statistical data on energy use and land use change, but differ in the way they calculate the trend, how they treat uncertainties in atmospheric concentrations, and how they account for confounding climatic variability.

Knorr explains: “Our apparently conflicting results demonstrate what doing cutting-edge science is really like and just how difficult it is to accurately quantify such data. We are just at the very edge of being able to detect a trend in the airborne fraction.

“The team of QUEST researchers at the University of Bristol are working closely together, and with other researchers in the field, to provide the most up-to-date results possible.”

Dr Jo House of Bristol University and an author on the Nature Geoscience paper says, “It is difficult to accurately estimate sources and sinks of CO2, particularly in emissions from land use change where data on the area and nature of deforestation is poor, and in modelled estimates of the land sink which is strongly affected by inter-annual climate variability.

“While the science has advanced rapidly, there are still gaps in our understanding.”

Despite the knowledge gaps, all authors are in agreement that the only way to control is through a drastic reduction in global CO2 emissions.

More information:

1) Trends in the sources and sinks of by Corinne Le Quéré et al is published online by Nature Geoscience on Tuesday November 17 2009.
2) Is the airborne fraction of anthropogenic CO2 emissions increasing? by Wolfgang Knorr was published online by on Saturday November 7 2009.

Provided by University of Bristol (news : web)

Explore further: Controversial new climate change results

Related Stories

Controversial new climate change results

November 10, 2009

(PhysOrg.com) -- New data show that the balance between the airborne and the absorbed fraction of CO2 has stayed approximately constant since 1850, despite emissions of CO2 having risen from about 2 billion tons a year in ...

Fossil fuel CO2 emissions up by 29 percent since 2000

November 17, 2009

The strongest evidence yet that the rise in atmospheric CO2 emissions continues to outstrip the ability of the world's natural 'sinks' to absorb carbon is published this week in the journal Nature Geoscience.

Emissions rising faster this decade than last

October 2, 2008

The latest figures on the global carbon budget to be released in Washington and Paris indicate a four-fold increase in growth rate of human-generated carbon dioxide emissions since 2000.

Emissions rising faster this decade than last

September 26, 2008

The latest figures on the global carbon budget to be released in Washington and Paris today indicate a four-fold increase in growth rate of human-generated carbon dioxide emissions since 2000.

Recommended for you

How a young-looking lunar volcano hides its true age

March 28, 2017

While orbiting the Moon in 1971, the crew of Apollo 15 photographed a strange geological feature—a bumpy, D-shaped depression about two miles long and a mile wide—that has fascinated planetary scientists ever since. Some ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.