Rivers melt Arctic ice, warming the air and ocean

A new study shows that rising heat from Arctic rivers is melting sea ice in the Arctic Ocean and warming the atmosphere.

The study published this week in Advances in science it was led by the Japanese Agency for Marine-Land Science and Technology, with authors in the United States, United Arab Emirates, Finland and Canada.

According to the research, major Arctic rivers contribute significantly more heat to the Arctic Ocean than in 1980. River heat is responsible for up to 10% of the total sea ice loss that occurred from 1980 to 2015 on the Arctic shelf region. Ocean. That melt equates to about 120,000 square miles of 1-meter-thick ice.

“If Alaska were covered in 1 meter thick ice, 20% of Alaska would have disappeared,” explained Igor Polyakov, co-author and oceanographer at the International Arctic Research Center and the Finnish Meteorological Institute of the University of Alaska. Fairbanks.

Rivers have the greatest impact during spring melt. Hot water spills into the ice-covered Arctic Ocean and spreads under the ice, decomposing it. Once the sea ice melts, warm water begins to warm the atmosphere.

Research has found that far more thermal energy from the river enters the atmosphere than that which melts the ice or warms the ocean. Since air is mobile, this means that the heat of the river can affect areas of the Arctic that are far from river deltas.

The impacts were most pronounced in the Siberian Arctic, where several large rivers flow into the relatively shallow shelf region stretching nearly 1,000 miles offshore. The Mackenzie River in Canada is the only river large enough to contribute substantially to the melting of sea ice near Alaska, but even the smaller rivers in the state are a source of heat.

Polyakov predicts that rising global air temperatures will continue to warm Arctic rivers in the future. As rivers warm up, more heat will flow into the Arctic Ocean, melting more sea ice and accelerating Arctic warming.

Rivers are just one of the many heat sources that are warming the Arctic Ocean. The entire Arctic system is in an extremely anomalous state as global air temperatures rise and warm Atlantic and Pacific water enters the region, decomposing sea ice even in the dead of winter. All of these components work together, causing positive feedback loops that accelerate warming in the Arctic.

“It’s very alarming because all of these changes are accelerating,” Polyakov said. “The rapid changes are simply incredible over the past decade or so.”