Why the Arctic route is heating up for global shipping

Researchers at Switzerland’s EPFL and the Swiss Federal Institute of Technology Lausanne studied how ship exhaust affects cloud formation and ice melt in the Arctic. Professor Julia Schmale and PhD student Benjamin Heutte spent a year on an Arctic research vessel, initially studying natural aerosols, but found their own exhaust fumes often drifted over their instruments. With summer Arctic air pollution generally near zero, they could examine the impact of one ship’s particulate matter on clouds. The team estimates that when pollutant-caused clouds sit above ice, emissions within about 100 meters could add roughly 1 mm of ice melt per day; clouds over water appear to cool instead. The research feeds into a wider concern as Arctic shipping traffic rises and sea ice declines.