Polar Stratospheric Cloud, Kiruna, Sweden (IMAGE) University of Maryland Caption Stratospheric clouds above the Arctic, like those seen here over Kiruna, Sweden, provide ideal conditions for chemical reactions that transform chlorine to a form that depletes the Earth's protective ozone layer. New research shows that unless greenhouse gas emissions are reduced, climate patterns that favor the formation of such clouds will continue to accelerate ozone loss. Credit Ross Salawitch/UMD Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.