Envisat makes first ever observation of regionally elevated CO2 from manmade emissions (Forwarded)
Andrew Yee
http://www.esa.int
18 March 2008
Envisat makes first ever observation of regionally elevated CO2 from manmade
emissions
Using data from the SCIAMACHY instrument aboard ESA's Envisat environmental
satellite, scientists have for the first time detected regionally elevated
atmospheric carbon dioxide -- the most important greenhouse gas that
contributes to global warming -- originating from manmade emissions.
More than 30 billion tonnes of extra carbon dioxide (CO2) is released into
the atmosphere annually by human activities, mainly through the burning of
fossil fuels.
According to the latest report by the Intergovernmental Panel on Climate
Change (IPCC), this increase is predicted to result in a warmer climate with
rising sea levels and an increase of extreme weather conditions. Predicting
future atmospheric CO2 levels requires an increase in our understanding of
carbon fluxes.
Dr Michael Buchwitz from the Institute of Environmental Physics (IUP) at the
University of Bremen in Germany and his colleagues detected the relatively
weak atmospheric CO2 signal arising from regional 'anthropogenic', or
manmade, CO2 emissions over Europe by processing and analysing SCIAMACHY
data from 2003 to 2005.
As illustrated in the image, the findings show an extended plume over
Europe's most populated area, the region from Amsterdam in the Netherlands
to Frankfurt, Germany.
Carbon dioxide emissions occur naturally as well as being created through
human activities, like the burning of fossil fuels (oil, coal, gas) for
power generation, industry and traffic.
"The natural CO2 fluxes between the atmosphere and the Earth's surface are
typically much larger than the CO2 fluxes arising from manmade CO2
emissions, making the detection of regional anthropogenic CO2 emission
signals quite difficult," Buchwitz explained.
"This does not mean, however, that the anthropogenic fluxes are of minor
importance. In fact, the opposite is true because the manmade fluxes are
only going in one direction whereas the natural fluxes operate in both
directions, taking up atmospheric CO2 when plants grow, but releasing most
or all of it again later when the plants decay. This results in higher
atmospheric CO2 concentrations in the first half of a year followed by lower
CO2 during the second half of a year with a minimum around August.
"That we are able to detect regionally elevated CO2 over Europe shows the
high quality of the SCIAMACHY CO2 measurements."
Buchwitz says further analysis is required in order to draw quantitative
conclusions in terms of CO2 emissions. "We verified that the CO2 spatial
pattern that we measure correlates well with current CO2 emission databases
and population density but more studies are needed before definitive
quantitative conclusions concerning CO2 emissions can be drawn."
Significant gaps remain in the knowledge of carbon dioxide's sources, such
as fires, volcanic activity and the respiration of living organisms, and its
natural sinks, such as the land and ocean.
"We know that about half of the CO2 emitted by mankind each year is taken up
by natural sinks on land and in the oceans. We do not know, however, where
exactly these important sinks are and to what extent they take up the CO2 we
are emitting, i.e., how strong they are.
"We also don't know how these sinks will respond to a changing climate. It
is even possible that some of these sinks will saturate or turn into a CO2
source in the future. With our satellite measurements we hope to be able to
provide answers to questions like this in order to make reliable
predictions," Buchwitz said.
By better understanding all of the parameters involved in the carbon cycle,
scientists can better predict climate change as well as better monitor
international treaties aimed at reducing greenhouse gas emissions, such as
the Kyoto Protocol which addresses the reduction of six greenhouse gases.
Last year, European Union leaders highlighted the importance of cutting
emissions from these manmade gases by endorsing binding targets to cut
greenhouse gases by at least 20 percent from 1990 levels by 2020.
[NOTE: Images and weblinks supporting this release are available at
http://www.esa.int/esaCP/SEMZHVM5NDF_index_1.html ]