Melting Glaciers Aren’t Just Raising Sea Levels, They’re Polluting the Oceans
The world’s melting glaciers and polar ice sheets don’t just threaten to flood the world’s coastal cities—they’re also releasing huge amounts of carbon into the ocean, according to a first-of-its-kind study published Monday.
The world’s oceans already are turning acidic as they absorb greenhouse gases resulting from the burning of fossil fuels. Carbon-containing ice sheets may not necessarily exacerbate acidification due to the counteracting flood of freshwater, but they could harm marine life, including fisheries humans depend on for food. And carbon released by mountain glaciers could affect freshwater aquatic life in streams and rivers.
Eran Hood is a professor of environmental science at the University of Alaska Southeast and the lead author of the study published in the journal Nature Geoscience on Monday. He said scientists are just beginning to research the impact of glacial and ice-sheet carbon on marine life.
“We do know, however, that the carbon released by glaciers is readily metabolized by aquatic microbes so changing the amount of carbon entering near-shore marine ecosystems has the potential to impact food webs,” Hood said in an email. “The impacts will likely be relatively localized however some of the glaciered coastal margins are quite large (Greenland or the Coast Mountains along the Gulf of Alaska) so the impacts to near-shore ecosystems in these regions could be fairly extensive.”
Hood and his colleagues who studied the carbon content of glaciers and ice sheets estimate that the flow of carbon will double over the next 35 years as climate change accelerates, according to the study. That means 15 teragrams—about 33 billion pounds—of carbon could be released by 2050.
Such carbon includes soot and other residues deposited on glaciers and ice sheets throughout the ages. Ice-bound carbon represents only 6 percent of the carbon stored in North American permafrost, which is being released as the Arctic thaws. But the scientists said glacier carbon could have an outsize impact.
That’s because the ice-released carbon is more easily absorbed by microscopic creatures and may ultimately end up in the atmosphere.