Arctic Ocean warmest in 2,000 years
Water flowing into the Arctic Ocean from the Atlantic Ocean is about 2°C warmer today than it has been for at least 2,000 years, according to a study published in Science. The findings add to the picture of Earth’s warming waters and melting sea ice, and the researchers suggest that the temperature rise is linked to amplification of climate change in the Arctic.
Researchers from the Leibniz Institute of Marine Sciences in Kiel, Germany, focused on the Fram Strait, which runs between Greenland and Norway’s Svalbard archipelago, and which hosts the biggest channel of warm water flowing into the Arctic. The current of warm water lies 50 metres below the surface, and can reach a balmy 6°C in summer – warm in comparison to the frigid Arctic, where icy surface waters can be -2°C.
The summer water temperatures, reconstructed from the makeup of tiny organisms buried in sediments in the Fram Strait, have risen from an average 5.2°C from 1890-2007 and about 3.4°C in the previous 1,900 years.
The findings were a new sign that human activities were stoking modern warming since temperatures are above past warm periods linked to swings in the sun’s output that enabled, for instance, the Vikings to farm in Greenland in Medieval times.
The authors wrote that the warming temperatures “are presumably linked to the Arctic amplification of global warming” and that the warming “is most likely another key element in the transition to a future ice-free Arctic Ocean.”
Source: Reuters, 28 January 2011