A study compiled by environmental physicists at the University of Bremen arrives at an unexpected conclusion: Europe’s forests absorb more carbon dioxide from the atmosphere than previously thought. In cooperation with international and German partners, including the Max Planck Institute for Biochemistry in Jena, they evaluated the CO2 data collected from two satellite instruments. The findings of their research on the European carbon sink were recently published in the internationally renowned journal “Atmospheric Chemistry and Physics” under the title “Satellite-inferred European carbon sink larger than expected”.
The research team spent eight years analyzing the copious data they obtained from the SCIAMACHY instrument on board the (since abandoned) European environmental research satellite ENVISAT, and one year of data collected by the Japanese GOSAT satellite. Using a newly developed analytical method they were able to show that the European biosphere absorbs about 0.6 billion tons of carbon more than had previously been assumed by the Intergovernmental Panel on Climate Change (IPCC).
The European carbon sink
Dr. Maximilian Reuter; the study’s lead author explains: “The existence of a large natural carbon sink in the central and northerly latitudes of the Northern Hemisphere was already known to science. Without it, the CO2 concentrations in our atmosphere would be significantly higher and the resulting climate warming even more acute. It wasn’t quite clear, though, exactly where the sink was located. We only knew for a fact that a large part of the natural carbon sinks are over the extratropical land masses of the Northern hemisphere. Decades of research had failed to determine the precise location of this important carbon sink, how it has changed over time, and how the vegetation on the Earth below would react to climate change. In order to find out, our study incorporates all the data on atmospheric CO2 concentrations we could find. We also included relatively new satellite measurements in the near infrared spectral range, a technique developed by our team”.
CO2 emissions must be further reduced
However, Dr. Michael Buchwitz, co-author of the study and a research associate at the University of Bremen’s Institute for Environmental Physics, is careful to point out that “our findings are no cause for complacency: We should on no account conclude that Europe can ease efforts to cut down on CO2 emissions. CO2 has a long life and is well-homogenized, making it a global problem. And we have no way of knowing just how long nature will continue doing us the favor of taking up such large quantities of the CO2 emitted by humans.”
More research necessary
The analysis of satellite data is a complex procedure: Even the smallest systemic error can lead to significant distortions in calculating the degree of carbon sink. This is because the CO2 concentrations in the atmosphere are already on a very high level so that even strong sources and sinks have only relatively low impacts. In order to arrive at more robust findings, the environmental researchers interspersed their data with a number of less-accurate analyses, supplementing their own satellite measurements with those of their Japanese and American counterparts. “The independent development of the applied five data products lowers the risk of shared error sources and contributes towards making our findings in respect of the derived carbon sink more robust”, Reuter explains. Nevertheless, much more research is needed before we will have a complete understanding of the global carbon cycle and the as yet unexplained different results obtained from the various data products applied. “This is what makes satellite measurements like the data recently sent back by NASA‘s OCO-2 satellite and the planned European CarbonSat so important”, adds Michael Buchwitz.
If you would like to have more information on this topic, please contact:
University of Bremen
Faculty of Physics / Electrical Engineering
Institute for Environmental Physics
Dr. Maximilian Reuter
Phone: +49 421-218-62085
e-mail: mreuterprotect me ?!iup.physik.uni-bremenprotect me ?!.de
Dr. Michael Buchwitz
Phone: +49 421-218-62086
e-mail: buchwitzprotect me ?!uni-bremenprotect me ?!.de
