Short-lived climate forcers

Temperatures in the Arctic have increased by almost twice the global average temperature over the last 100 years. This has led to earlier melting in the spring and a reduction of Arctic sea ice. Emissions of CO2 are the main culprit when it comes to climate, but more short-lived drivers such as methane, tropospheric ozone and aerosols also play a role – which in the Arctic is disproportionately large. These pollutants have received increased attention in recent years, particularly through the IPY research project called POLARCAT.

The most important way to reduce global warming is to significantly reduce CO2 emissions. However, this will not be enough. CO2 has a very long lifetime in the atmosphere, and the climate effects of CO2 reductions will probably come too late to prevent the rapid melting of the Arctic. But if we succeed in reducing the concentration of methane and other pollutants, researchers believe that the melting can be slowed.

Methane, which is the second most important greenhouse gas after CO2, has a lifespan of around 10 years. It is itself a potent greenhouse gas, but also leads to the formation of ozone, a powerful greenhouse gas. Ozone has a life span of a few weeks to months, and is formed with other polluting gases such as nitrogen oxides, carbon monoxide and volatile organic compounds. Finally, tropospheric aerosols, including soot, also have an impact on global warming in the Arctic. Aerosols have a lifetime of about a week.

Although methane in particular can come from natural sources (see greenhouse gases), short-lived climate drivers are largely man-made. Soot, methane and ozone are transported to the Arctic from automobile traffic, agriculture and industry in Europe, the USA and Russia. Climate drivers account for about 45% of the total greenhouse gas emissions. Due to their short lifespan, a reduction in emissions of these gases will have an immediate effect in the Arctic.