The Arctic is warming two or three times faster than the rest of the planet. This amplified warming is due to several factors, but the relative importance of each one remains still unclear. “We do know, however, that clouds could play an important role,” says Julia Schmale, an EPFL professor who heads the Extreme Environments Research Laboratory and holds the Ingvar Kamprad Chair. “By reflecting the sun’s rays back into space or trapping heat close to the Earth’s surface like a blanket, clouds help either cool off or warm up the planet.”
Schmale—along with scientists from the Paul Scherrer Institute’s Laboratory of Atmospheric Chemistry and Stockholm University’s Department of Environmental Science and Bolin Center for Climate Research—spent several weeks collecting data near the North pole in August and September 2018, as part of the US-Swedish expedition Arctic Ocean 2018 on board the Swedish icebreaker Oden. The scientists measured the chemical and physical properties of atmospheric molecules and aerosol particles to better understand the conditions leading to cloud formation.
How aerosols are formed in the Arctic
“One of our objectives was to investigate how new aerosol particles could form in the Arctic atmosphere,” says Andrea Baccarini, a Ph.D. student at the Paul Scherrer Institute and now scientific collaborator in the extreme Environments research Laboratory. “Under the right conditions, gas molecules condense together into small clusters that can grow, eventually forming aerosols.” If these aerosols grow even just a small amount larger, they can function as cloud condensation nuclei, which are essential for cloud formation.
In the Arctic summer and fall, the concentration of aerosols is extremely low. “The contribution of newly formed aerosols can be extremely important and even a small change in aerosol concentration in the high Arctic could have a major impact on cloud formation