Envisat Makes First
Ever Observation Of Regionally Elevated CO2 From Manmade
Emissions
(18 March 2008) 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.
Using data acquired from 2003-2005 by 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. the findings show an extended plume over Europe’s most populated area, the region from Amsterdam in the Netherlands to Frankfurt, Germany. (courtesy: ESA - DLR - IUP, Univ.Bremen)
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."
CO2 measurements over the Northern Hemisphere obtained at the Earth’s surface (thin lines) from Envisat’s SCIAMACHY instrument (thick yellow line and two northern hemispheric maps). This figure highlights the natural fluxes of CO2 which, unlike manmade CO2 fluxes, operate in both directions – taking up atmospheric CO2 during spring and summer when plants grow, but releasing most or all of it again later in the year, 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. (courtesy: ESA - DLR - IUP, Univ.Bremen)
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.
(source: ESA)
|
||||||||||||
