The drastic reduction of Arctic sea ice within the last decade is an environmental concern for Canada. In 2008, the loss of ice reached a mass of one million square kilometres, spanning a total area roughly the size of Ontario.  Environment Canada (EC) scientists were part of a recent study that investigated the impacts of this loss of Arctic sea ice on atmospheric chemistry in the lower atmosphere (troposphere) over the Arctic. The research compared for the first time, satellite observations of bromine monoxide with field measurements of bromine monoxide, ozone and gaseous elemental mercury in the Arctic. With the environment in the Arctic a high priority issue for the federal government, information gathered from studies such as this generates important knowledge and understanding for decision makers and Northerners who will need to adapt to their changing environment.

The scientists in this study found that when the perennial sea ice melts, the vast areas are replaced with younger, seasonal sea ice with a much higher salt content. This salt reacts with sunlight and frigid temperatures, releasing bromine and chlorine into the troposphere. This then contributes to the depletion of ground-level ozone and the deposition of toxic atmospheric mercury into the Arctic, affecting both the health of humans and that of the ecosystem.   

The study collated measurements from multiple coordinated research projects during the International Polar Year,  including the Ocean Atmosphere Sea Ice Snowpack (OASIS)-Canada campaign led by EC scientists, the Circumpolar Flaw Lead System Study (for which EC scientists were co-principal investigators), as well as the U.S. State of Arctic Sea Ice Cover project. 

EC scientists are continuing to research the links between bromine sources, transport processes and the Arctic sea ice and are participating in a NASA-led field study taking place off the coast of Alaska in Spring 2012. This continuing research, combined with increased use of satellite measurements, will help provide accurate projections of both Arctic changes and their impacts.

Contact: Alexandra (Sandy) Steffen, 416-739-4116, Air Quality Research