To protect human health and safeguard the environment, governments and utility companies around the world have worked -- successfully -- to reduced the amount of sulfur dioxide released into the atmosphere.
But there's a downside to cleaning the air of sulfur dioxide and similar pollutants: Arctic sea ice is more exposed to solar heat, and more of it melts.
Now, Environment Canada researchers, in a study published in Geophysical Research Letters, have put a number on the sea-ice melt that reduced emissions of sulfur dioxide (and certain other aerosols, tiny particles that are suspended in the atmosphere) are expected to cause: about 400,000 square miles or 1 million square kilometers.
That's the amount of ice melt, according to the study's calculation, that's likely to be attributable to reductions of human-caused emissions of sulfur dioxide and similar light-reflecting air pollutants by the end of the century. That figure will account for 25 to 40 percent of the expected seasonal sea-ice melt, depending on future emissions of carbon dioxide and other greenhouse gases, the study says.
That doesn't mean there should be a slowdown in air-quality controls, said one of the study’s authors.
“We want to avoid that interpretation,” said Nathan Gillett, an Environment Canada research scientist and manager of the Canadian Centre for Climate Modelling and Analysis.
Removing sulfur dioxide and other pollutants from the air is important to protect people and the environment, even if it also removes some material that shields Arctic sea ice from melt, Gillett said.
“We’re really just pointing out that it’s part of the picture and should be considered,” he said. “We’re not trying to weigh costs and benefits of sulfur dioxide here."