Heat escaping from the depths of the Arctic Ocean and rising to the surface could accelerate ice melt in the region, new research has revealed.
Greater exposure to wind on the surface of the Arctic — because of melting ice — has created underwater waves that are mixing warmer currents from the ocean depths with cooler surface waters. This, in turn, could accelerate further ice melt.
“There’s a reservoir of heat in the Arctic Ocean, well beneath the surface, that historically — when there’s been a lot of ice — has been fairly quiescent,” Dr Jen MacKinnon, chief scientist of the ArcticMix mission, told the BBC. “It’s just been sitting as a warm, salty puddle beneath the surface.”
The heat rising from the bottom of the ocean is the equivalent strength of the autumn Sun, and has led to temperatures of six degrees Celsius in waters down to 50 metres. The more the ocean is exposed to wind, due to melting surface ice, the more the heat may rise, creating a cycle of warming in the ocean.
The implications are significant. The stirring of these warmer waters could have already been accelerating ice melt and rising temperatures. To assess the impact this ice may have, they now need to quantify how much heat has mixed and the amount of melting it has caused.
The researchers, from the Scripps Institution of Oceanography at the University of California San Diego, were on a month-long voyage monitoring the end of the 2015 melt season — an annual melting and re-freezing of Arctic ice — when they made the discovery. The team will now need to analyse their findings and determine what the impact of these warmer currents could have on Arctic ice.
“The strength of [these currents] has been incredible,” said Dr MacKinnon. “We now need to disentangle what the contribution of that process is to the multi-year, inexorable decline of the sea ice.”
The team hopes that further research will improve the accuracy of climate forecasts in the region.
This year, Arctic ice coverage reached its fourth lowest level since records began. The consequences of ice melt could be fatal, and not just because of rising sea levels — most recently it was revealed that ancient viruses could be released by melting Arctic ice.
Source | http://www.wired.com