Flawed Climate Models? Arctic Ocean Started Getting Warmer Decades Earlier Than Thought

An international group of researchers reconstructed the recent history of ocean warming at the gateway to the Arctic Ocean in a region called the Fram Strait, between Greenland and Svalbard, says SciTech Daily.

Using the chemical signatures found in marine microorganisms, the researchers found that the Arctic Ocean began warming rapidly at the beginning of the last century as warmer and saltier waters flowed in from the Atlantic – a phenomenon called Atlantification – and that this change likely preceded the warming documented by modern instrumental measurements.

Since 1900, the ocean temperature has risen by approximately 2 degrees Celsius, while sea ice has retreated and salinity has increased.

The results, reported in the journal Science Advances, provide the first historical perspective on Atlantification of the Arctic Ocean and reveal a connection with the North Atlantic that is much stronger than previously thought.

The connection is capable of shaping Arctic climate variability, which could have important implications for sea-ice retreat and global sea level rise as the polar ice sheets continue to melt.
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The researchers used geochemical and ecological data from ocean sediments to reconstruct the change in water column properties over the past 800 years.

They precisely dated sediments using a combination of methods and looked for diagnostic signs of Atlantification, like change in temperature and salinity.

“When we looked at the whole 800-year timescale, our temperature and salinity records look pretty constant,” said co-lead author Dr. Tesi Tommaso from the Institute of Polar Sciences of the National Research Council in Bologna.

“But all of a sudden at the start of the 20th century, you get this marked change in temperature and salinity – it really sticks out.”

Full article here.