Restrictions on air pollution affect climate in Arctic

Restrictions on emissions of air pollution could slow down climate change in the Arctic. The results would be faster than from a reduction in carbon dioxide emissions. The crucial factor, however, is which emissions should be reduced, because some air pollutants increase heating and others cool down the earth. This is shown by a new study published in Nature Climate Change.

Over the last few decades, the temperature in the Arctic has increased twice as fast as the global average. Large reductions in global carbon dioxide emissions are needed to curb this rise. There are other methods of achieving positive effects for the climate, however, such as reducing climate change pollutants like soot and methane.

“Restricting these pollutants would improve the climate faster than restrictions on carbon dioxide emissions. It would also have large side effects in the form of improved air quality,” says Joakim Langner, researcher at SMHI and co-author of a study published in the Nature Climate Change journal.

Mapping the origins of air pollution

The study is the first major mapping of Arctic climate change through regional emissions of climate air pollutants. Pollutants included in the study were soot, sulphur dioxide, nitrogen dioxide, volatile organic compounds, organic carbon and tropospheric ozone.

“We can see that the major contributors to climate change in the Arctic are emissions from Asian countries, due to the high quantities of emissions. But measured per amount of pollution released, the Arctic is most sensitive to emissions within the area around the Arctic,” says Joakim Langner.

Air pollution affects climate in several ways

Different air pollutants have different effects on the climate, some contributing to heating and others to cooling. For example, soot emissions contribute to heating, while sulphur dioxide emissions have a cooling effect.

“There is a problem when it comes to taking action here, since there are good reasons for reducing sulphur emissions from a health and environmental perspective. One remaining problem is the considerable uncertainty regarding knowledge of how air pollution affects the climate. This applies particularly to the effect on clouds and how the deposition of soot on snow and ice affects their melting,” says Joakim Langner.

Technically feasible limits

Far-reaching global restrictions on emissions of climate changing air pollution that are technically feasible for the period 2015-2030 could reduce heating by 0.2 degrees by 2050, in a scenario that focuses on the reduction of soot emissions. That is nearly the equivalent of one decade of temperature increase at the current rate of increase in the Arctic.

In the longer term, only the reduction of CO2 emissions can slow the rise in temperature.