Arctic Ocean Increasingly "Warm, Fresh & Sour" As Acidification & Melting Accelerate

From the deck of a Norwegian research ship, the ravages of climate change in the Arctic are readily apparent. In the Fram Strait, the ocean passageway between Norway’s Arctic islands and the east coast of Greenland, seas that should be ice-covered in early September shimmer in the sunlight. Glaciers that muscled across mountains a decade ago are now in rapid retreat, leaving behind walls of glacial till. Rivers of meltwater gush off the Greenland Ice Sheet. But some of the biggest changes taking place in these polar seas are invisible. Under disappearing ice cover, these waters are rapidly growing more acidic as decades of soaking up humanity’s carbon emissions take their toll on ocean chemistry.

A soup of brash ice — the wreckage of old floes — surrounds the RV Kronprins Haakon as Colin Stedmon crouches on deck filling bottles with water that has just been hoisted from the ocean depths. The 329-foot icebreaker is steaming 700 nautical miles south of the North Pole on a Norwegian Polar Institute research cruise studying climate change impacts in this gateway to the Arctic Ocean. The samples of dissolved carbon, pH, and other measurements being collected by Stedmon, a chemical oceanographer from the Technical University of Denmark, will reveal how rapidly acidification is intensifying.

“Warm, fresh, and sour,” says Stedmon of the changes sweeping Arctic seas, which, along with the Southern Ocean surrounding Antarctica, are acidifying faster than any other marine waters on the planet. He and the rest of the crew of researchers from across Europe are trying to decipher how a warming Arctic is, as Stedmon puts it, “melting ice, freshening seawater, and reducing its ability to resist acidification.”

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Acidification is underway throughout the world’s oceans, according to a new Oceans and Cryosphere report by the Intergovernmental Panel on Climate Change. But the various ocean regions will respond differently to the same amount of carbon dioxide, says Alessandro Tagliabue, a University of Liverpool biogeochemist and one of the lead authors on the ocean changes chapter of the report. As our carbon emissions continue to soar, acidic conditions will race across the high latitudes first, according to the report. And Arctic ecosystems and people — already stressed by rising temperatures, vanishing ice, and the myriad other effects of climate change — are particularly threatened by acidification’s impacts. “The polar regions are especially vulnerable because of a systemic vulnerability that is linked to their chemical states today, which makes them very, very close to tipping over the edge into extremes of acidification,” says Tagliabue.

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https://e360.yale.edu/features/why-rising-acidification-poses-a-special-peril-for-warming-arctic-waters