Carbon counting becomes more accurate

Estimating how much carbon human activity releases into the atmosphere, and where it is concentrated, is getting more accurate thanks to German scientists who have recently analysed new satellite data.

The UK Met Office is also sharing its data at a conference in India this week to show more accurately how climate change is affecting agriculture and other human activities.

Dr Michael Buchwitz and his colleagues from the Institute of Environmental Physics (IUP) at the University of Bremen detected the relatively weak atmospheric CO2 signal arising from regional “anthropogenic” (manmade) CO2 emissions over Europe, by processing and analysing data collected from 2003 to 2005 by the Sciamachy instrument on board the European Space Agency’s Envisat earth-observation satellite.

This is the first time scientists have detected regional increases in atmospheric carbon dioxide. Human carbon emissions are normally eclipsed by much larger natural sources of carbon emission and reduction, so figures for anthropogenic carbon emission - some 30bn tonnes annually - were estimated on global scales previously.

The work by Buchwitz and his colleagues is expected to help governments, companies and other agencies more accurately measure and therefore manage atmospheric carbon emissions.

According to S2 Intelligence, an Australian-based consultancy, businesses will spend $595 billion by 2010 on systems to monitoring how much carbon they emit.

Unsurprisingly, European carbon emissions are concentrated over Europe’s most populated area, the region from Amsterdam in the Netherlands to Frankfurt in Germany.

“The manmade [changes in carbon emission] are only going in one direction whereas the natural changes operate in both directions, taking up atmospheric CO2 when plants grow, but releasing most or all of it again later when the plants decay,” said Buchwitz.

Buchwitz added that 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," he said.

Significant gaps remain in the knowledge of carbon dioxide’s sources, such as fires, volcanic activity and the respiration of animals, and its natural sinks, such as plants or algae and the oceans.

"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,” said Buchwitz.

"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 these 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 that addresses the reduction of six greenhouse gases.

At the climate conference in India, computer models from the Met Office Hadley Centre and other UK science centres will be used to examine a range of impacts including how agriculture and cities will be affected by changes to the climate.
"The worldwide issue of climate change and the impacts it brings, make it extremely important that we pool our knowledge on a global scale,” said Met Office climate scientist Mark McCarthy, who is leading the workshop. “At the same time we can focus our attention on specific parts of the world to provide regional predictions for the decades ahead.”