Atlantification "EMPOWER IAS"

In news:

• Scientists have uncovered “hotspots” where some parts of the Barents Sea are starting to more closely resemble the Atlantic. They call this phenomenon “Atlantification”.

 

Atlantification

• Streams of warmer water from the Atlantic Ocean flow into the Arctic at the Barents Sea.
• This warmer, saltier Atlantic water is usually fairly deep under the more buoyant Arctic water at the surface.
• Lately, however, the Atlantic water has been creeping up. That heat in the Atlantic water is helping to keep ice from forming and melting existing sea ice from below.
• This process is called “Atlantification”.
• The ice is now getting hit both from the top by a warming atmosphere and at the bottom by a warming ocean.

 

Sea change

• Sea ice plays a key role in keeping the northern Barents Sea in its Arctic climate regime. In addition to the sea ice that forms on its surface, the region receives an “import” of sea ice each year, blown in from the central Arctic by the wind.
• When the imported sea ice melts in spring and summer, it provides an influx of freshwater to the Barents Sea. This cold, fresh water top-ups the Arctic layer of the northern region, helping to maintain the stratification that works as a barrier to the warm Atlantic waters below.
• But the amount of ice the Barents Sea receives each year is declining. The average annual area of ice import during 2000-15 was around 40% smaller, on average, than during 1979-2009, the study finds. The decrease in volume of sea ice imported “was even larger”, the study says, at approximately 60%.
• This is in line with the observed decline in Arctic sea ice cover more widely in response to rising temperatures, the paper says, which reduces “the probability of large sea ice inflows to the Barents Sea, in both volume and area”. Less sea ice means less freshwater being imported into the northern Barents Sea.

 

Reasons for it:

 

 

• The Arctic sea ice extent and thickness have been dropping for decades as global temperatures rise.
• As the Arctic loses ice and the ocean absorbs more solar radiation, global warming is amplified.
• That affects ocean circulation, weather patterns and Arctic ecosystems spanning the food chain, from phytoplankton all the way to top predators.