Scientists working at the Institute for Environmental Physics (IUP) at the University of Bremen have come up with some good news mixed with some bad news concerning emissions and resulting atmospheric concentrations of the most important gaseous nitrogen oxide (“NOx”, a mixture of the two toxic gases NO2 and NO) and the greenhouse gas carbon dioxide (CO2).
This is evident from an article published yesterday in the renowned journal “Nature Geoscience”. Whereas in Europe and North America there is a noticable trend toward lower emissions, in Asia, and in particular China, the clear upward trend continues. But there is also some good news mixed with the bad: In relation to the CO2 emissions, there has been a significant fall in emissions of nitrogen oxides. This shows that in China the growing use of modern – and consequently cleaner – technologies is producing less toxic nitrogen oxide per unit of fossil fuel consumed.
Researchers at the University of Bremen have shown that the CO2 emissions in East Asia increased on average by 9.8% in the period 2003-2011, whereas in the same period emissions of nitrogen oxide grew by “only” 5.8% – that is significantly less compared to CO2 (see attached figure). The rapid rise in emissions in China is clearly a consequence of the country’s runaway economic growth.
The toxic nitrogen oxides are caused to a large extent by high-temperature combustion in automobiles and industry, i.e. processes that typically also produce large amounts of CO2. Unless it is present in high concentrations, CO2 is not toxic – although it does have a strong negative effect on our climate. Higher concentrations of CO2 lead to climate warming, with all its negative associations.
Data collected by SCIAMACHY
The research team at the University of Bremen gleaned the information for their study from data obtained via the satellite instrument SCIAMACHY. The lead investigator of the SCIAMACHY mission is Professor John P. Burrows from the University’s Institute for Environmental Physics. SCIAMACHY is a German-Dutch-Belgian satellite instrument that was installed on the ESA’s European environment satellite ENVISAT. ENVISAT went into orbit in 2002, and for over ten years it successfully sent back data for the researchers to evaluate. Unfortunately, for as yet unexplained reasons, contact with ENVISAT broke off in April 2012.
The lead author of the article in Nature Geoscience, Maximilian Reuter, explains how the data for the study were obtained: “CO2 and nitrogen oxide are gases released during the combustion process of fossil fuels. The satellite instrument SCIAMACHY is able to measure the concentrations of both these gases. The nitrogen oxides have a very short life (hours) compared to C02 (decades). They are therefore good tracers or markers that when used together with a newly developed filter technology allow the signal caused by the CO2 emissions produced by humans to be separated from the overlapping signal caused by the CO2 released and absorbed by plants. This new technique means we are now even able to detect the “weekday effect” of CO2 from outer space. For instance, we can see that on weekends in Europe and America somewhat less CO2 is released into the atmosphere than on weekdays. This demonstrates the high accuracy of the new method”.
Co-author, Dr. Michael Buchwitz from the University of Bremen adds: “Unfortunately, for now and in the near future there is no other satellite capable of measuring with any accuracy the CO2 emissions produced by municipalities, power stations, volcanoes and other important sources of CO2 emissions.” The Bremen environmental scientists are therefore pinning their hopes on their proposal for a CarbonSat mission. “Temporarily, we are able to use existing satellites for a special measuring method based on observations of nitrogen oxides. Sometime in the future, though, we must once again be in a position to trace important sources of CO2 emissions from space, in order, for instance, to be able to verify the CO2 emissions reported within the context of international agreements on climate control”, says Buchwitz.
The main findings of the study were published in late September 2014 in Nature Geoscience.
If you would like to have more information on this topic, please contact:
University of Bremen
Institute for Environmental Physics
Maximilian Reuter
e-mail: mreuterprotect me ?!iup.physik.uni-bremenprotect me ?!.de
Dr. Michael Buchwitz
e-mail: Michael.Buchwitzprotect me ?!iup.physik.uni-bremenprotect me ?!.de