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Rivers melt ice in the Arctic, warming the air and oceans



Rivers melt ice in the Arctic, warming the air and oceans

Water from Canada̵

7;s Mackenzie River flows into the clear, blue Arctic Ocean in July 2012. The white areas in the upper half of the photo are mostly sea ice, while the areas below are clouds on land. Image provider: NASA Earth Observatory

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


The study is published this week in Scientific advance is led by the Japan Sea-Earth Science and Technology Agency, with contributors in the United States, United Arab Emirates, Finland and Canada.

According to the study, the large rivers in the Arctic contribute significantly more heat to the Arctic Ocean than in 1980. Heat from rivers is responsible for up to 10% of total sea ice loss between 1980 and 2015. on the shelf of the Arctic Ocean. That melts the equivalent of about 120,000 square miles of ice 1 meter thick.

Igor Polyakov, co-author and oceanographer at the International Arctic Research Center at the University of Alaska Fairbanks and the Finnish Meteorological Institute, explains: “If Alaska is covered by a 1m thick layer of ice, 20% of the area Alaska area will disappear.

Rivers that have the greatest impact during the spring split. The warm water that poured into the Arctic Ocean covered the ice and spread under the ice, causing it to decompose. As the sea ice melted, the warm water began to heat the atmosphere.

Research shows that a river’s thermal energy enters the atmosphere more than it melts the ice or heats the ocean. Since the air is mobile, this means that river temperatures could affect areas in the Arctic far from the river deltas.

Rivers melt ice in the Arctic, warming the air and oceans

This chart shows the relative warming caused by rivers in the Arctic, with heat sources in orange and heat sinks turquoise. In the spring, rivers flow into the Arctic Ocean, warming the water and thawing the sea ice, thereby warming the atmosphere. A feedback occurs when the reflective ice disappears, allowing dark seawater to absorb more heat and melt more sea ice. Credit: Image adapted from Science Advances

The effects are most pronounced in the Arctic Siberia, where many large rivers flow into the relatively shallow continental shelf area extending nearly 1,000 miles offshore. Canada’s Mackenzie River is the only river large enough to make a significant contribution to sea ice melting near Alaska, but the state’s smaller rivers are also a source of heat.

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

Rivers are just one of the many heat sources that are currently warming the Arctic Ocean. The entire arctic system is in an extremely abnormal state as global air temperatures rise and warm water in the Atlantic and Pacific Oceans floods the region, causing sea ice to decompose even in the middle of winter. . All of these components work together, creating positive feedback loops that increase the rate of warming in the Arctic.

“It’s alarming because all these changes are accelerating,” said Polyakov. “The rapid changes have been just amazing over the past decade.”


The arctic anchoring the ocean sheds light on the loss of ice in the winter sea


More information:
The increase in riparian heat flows causes the arctic sea ice depletion and the warming of the oceans and the atmosphere, Scientific advance (Year 2020). DOI: 10.1126 / sciadv.abc4699, advanced.sciencemag.org/content/6/45/eabc4699

Provided by University of Alaska Fairbanks

Quote: Arctic rivers thaw, warm air and oceans (2020, November 6) accessed November 7, 2020 from https://phys.org/news/2020-11- rivers-arctic-ice-air-ocean.html

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