Asia is warming the Arctic

In a study headed by CICERO researcher Maria Sand, the researchers have conducted hundreds of simulations with advanced models to investigate how current black carbon and sulphur emissions and other pollution from various countries are distributed in the atmosphere.

"The Arctic is warming twice as fast as the rest of the world, resulting in melting sea ice and an earlier onset of spring. While large cuts in CO₂ emissions are needed to stop the temperature increase, carbon black emissions also play a critical role in the Arctic. The area is covered by ice and snow, which has a cooling effect because it reflects the sunlight. When the ice turns dark from soot, the heat is absorbed, the snow melts faster and temperatures rise even more," says Sand.

Unlike CO₂, black carbon disappears from the atmosphere within one week. Today the effect of emission cuts is noticed in the course of a politician's term. Cuts in emissions also improve the local air quality. This has made black carbon a politically relevant issue. In order for anti-emission measures to have the greatest impact, the decision-makers must know which sources contribute the most to rising temperatures.

"Our simulations show that the greatest warming in the Arctic is caused by emissions in Asia. The emissions from the industrial sector contain a great deal of sulphur. These particles are light and thus have a cooling effect. However, Asian households produce a large amount of soot when they cook food and heat their homes. Indoor food preparation on ovens that don't burn clean are primarily a health problem, but it is a problem for the climate as well," explains Sand.

The World Health Organization estimates that 4.3 million people die each year from indoor air pollution, caused mainly by heating and cooking with ovens fuelled by coal, wood and manure. These emissions also promote warming in the Arctic. Emissions from Asia contribute the most to Arctic warming because the volume is so large. Emissions closer to the Arctic, such as oil production in Russia and wood heating in Norway, increase temperatures far more per kilo emission. Although these emissions are relatively small, reducing them can be very effective.

Sand's study presents detailed calculations of the effect of black carbon emissions on temperature from various sources and regions. Together with cost estimates of anti-emission measures, the study provides valuable knowledge that decision-makers can use to assess which measures are the most cost effective.

"According to our calculations, warming in the Arctic can be reduced by 0.2 °C by 2050 by making major emission cuts in those sectors that cause the greatest warming," concludes Sand.