The Arctic has been warming at the fastest rate of any place on Earth.  There have long been observations of amplification of Arctic warming, meaning that its temperature increases have been well above what would be expected from the global temperature rise.

Many climate models have attributed this warming to the melting of sea

ice.  As the bright white ice disappears

for longer periods of the year, the dark surface waters that are exposed absorb

sunlight rather than reflecting it back into space the way the ice does.  This is known as the ice-albedo feedback.  But it does not entirely explain the amount

of warming in the Arctic.

Researchers at the Scripps Institution of Oceanography have developed

a new theory that helps to explain what is going on.

In the areas of the Arctic Ocean where there is sea ice, the water is

actually warmer at depth and colder near the surface.  The deeper waters are fed by the relatively

warm Pacific and Atlantic Oceans while the surface water is cooled by the ice.  The increasing temperature difference between

surface and deeper water causes a greater upward flow of heat.  This was first observed in research cruises

that revealed evidence that the Arctic Ocean water was becoming more turbulent

over time.

According to computer modeling, this phenomenon is responsible for

about 20% of the amplification of global warming that occurs in the Arctic.

There are multiple ongoing studies looking at the Arctic warming

trend.  Other factors that have

contributed over time are the presence of chlorfluorocarbons in the

atmosphere.   That contribution is waning

since the use of CFCs has been phasing out over time.

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Researchers Find New Reason Why Arctic is Warming So Fast

Photo, posted April 19, 2017, courtesy of Markus Trienke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.