An international research team led by the University of Leipzig used satellite data to demonstrate that the concentration of polluting particles has decreased significantly since 2000. This is necessary because of their impact on health. But it is also of great importance as it reduces the cooling effect of particles on the climate. The results of the study were published in the journal Chemistry and physics of the atmosphere.
Global warming is caused by the emission of greenhouse gases. According to the Intergovernmental Panel on Climate Change (IPCC), temperatures have risen by 1.1 degrees Celsius by 2019 compared to pre-industrial levels. However, at the same time, the burning of fossil fuels emits aerosolsin the form of particulate pollutants such as soot or sulfuric acidwhich cool our climate.
They reflect sunlight and also increase the reflectivity of clouds. According to the IPCC, the presence of aerosols in the atmosphere caused the climate to be 0.5 degrees Celsius cooler in 2019 than without them. Other effects, such as land use change, also play a role.
Research documents widespread evidence of this declining climate cooling effect
In a new international analysis, Professor Johannes Kuas, a meteorologist at the University of Leipzig, and colleagues from across Europe, China and the US have documented strong evidence for this impact of improved air quality on climate.
“We analyzed data from NASA’s Terra and Aqua satellites. They have provided comprehensive satellite observations of the Earth since 2000, measuring incoming and outgoing radiation as well as cloud and aerosol pollution. The latter has decreased significantly in North America, Europe and East Asia since 2000,” says Professor Johannes Kuas, lead author of the study, which was initiated during a meeting of the two European research projects CONSTRAIN and FORCES.
The reduction in aerosol-induced cooling increases the warming due to CO2 from 2000 to 50%
It also reduced the cooling effect of aerosols. Compared to 2000, this has led to an increase in the warming effect of up to 50% of that of CO2 increases over the same period. This means an acceleration of global warming factors compared to the previous period.
“Our research should not be interpreted to mean that we should emit more aerosols to cool the climate. On the contrary: aerosols are harmful to human health and the environment, so we need to keep reducing emissions,” Kuas concludes. This is why air quality legislation has been getting stricter since the 1970s and is being implemented in more and more countries.
Professor Kuas and his colleagues in the new study highlight the increasingly urgent need for rapid and deep reductions in greenhouse gas emissions.
Johannes Quaas and others. Strong evidence of changing trends in effective aerosol forcing on climate, Chemistry and physics of the atmosphere (2022). DOI: 10.5194/acp-22-12221-2022
University of Leipzig
Citation: Improvements in air quality found to have accelerated global warming in recent decades (September 21, 2022) Retrieved September 21, 2022, from https://phys.org/news/2022-09-air-quality-global-decades. html
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