PR — 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.
Elevated CO2 over Europe
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.
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."
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
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