Our living planet: Earth’s ‘CO2 breathing’ and more seen from space

Posted by pt91 at Sep 04, 2013 01:20 PM |
University of Leicester scientists involved in project to map global distribution of climate relevant gases from space

Issued by University of Leicester Press Office on 4 September 2013

Contact pressoffice@le.ac.uk to request images

10 years of satellite observations of greenhouse gases have revealed that atmospheric carbon dioxide continues to increase despite international efforts to reduce carbon emissions and that the recent methane increases are most likely also mainly due to manmade emissions.

The results of these observations are to be presented at the European Space Agency’s Living Planet Symposium 9-13 September 2013 by researchers from the University of Leicester and the University of Bremen.

Atmospheric carbon dioxide and methane are the two most important manmade greenhouse gases responsible for global warming.

Measurements from ESA’s Envisat mission and Japan’s Greenhouse gases Observing Satellite, GOSAT, show that carbon dioxide increased by about 0.5% every year between 2003 and 2013. After years of stability, methane began increasing by 0.3–0.5% per year from 2007 on.

The main reason for the increase in carbon dioxide over the last ten years is emissions from burning fossil fuels, such as coal, oil and gas. For methane the reason is less clear, but is most likely due to increasing manmade emissions, combined with natural variations caused by wetland emissions and biomass burning.

In addition to the increase in greenhouse gases, the satellites also show many other features such as the gases’ detailed geographical pattern and fluctuations with time.

For carbon dioxide, seasonal fluctuations are the largest, caused by variations in the photosynthesis of vegetation. The observed ‘breathing’ is largest in northern mid to high latitudes. This is expected since there the carbon exchange between the atmosphere and vegetation is particularly large, with forests sequestering carbon during the summer (‘inhaling’), part of which is released during winter (‘exhaling’).

“Some carbon dioxide models tend to underestimate the strength of the ‘breathing’, but we have to investigate this further using different models and methods,” said Dr Michael Buchwitz from Germany’s University of Bremenn, who is the Science Leader of the greenhouse gas GHG-CCI project under ESA’s Climate Change Initiative.

“The goal of the GHG-CCI project is to generate high-quality global distributions of atmospheric carbon dioxide and methane, yielding improved information about the regional sources and sinks of these two important climate relevant gases. This is needed to improve climate predictions,” he said.

Dr Hartmut Boesch and Dr Robert Parker of the University of Leicester’s Department of Physics and Astronomy are generating carbon dioxide and methane datasets from GOSAT, the first dedicated greenhouse gas satellite launched by the Japanese space agency in 2009, which extends the time series obtained by the recently ended SCIAMACHY mission.

“Without the GOSAT mission, we would currently not have a suitable satellite mission in space that can observe carbon dioxide and methane and the time series obtained from SCIAMACHY would be interrupted.” says Dr. Hartmut Boesch who is leading the Leicester contributions to the GHG-CCI project and who is also the project manager.

Dr Robert Parker says “Satellites provide us with an unique picture of the distribution of atmospheric carbon dioxide and methane that cannot be obtained from the ground which will help us to better understand  where these gases are emitted and where they are absorbed.”

The latest results of these and related activities will be presented at ESA’s Living Planet Symposium in Edinburgh, 9-13 September 2013.

ENDS

Notes to editors:

For more information, please contact Dr Hartmut Boesch on hb100@leicester.ac.uk.

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