Deep Arctic Ocean warming enhanced by heat transferred from deep Atlantic

Area of Science:

• Oceanography
• Climate Science
• Arctic Studies

Background:

• Widespread warming observed in the deep and bottom Arctic Ocean since the 1990s.
• Attribution of deep Arctic warming has historically focused on geothermal heating.
• The influence of global and Arctic climate change on deep ocean warming remains unclear.

Purpose of the Study:

• To investigate the drivers of deep and bottom Arctic Ocean warming.
• To quantify the rate of warming in specific Arctic basins.
• To determine the impact of climate change on deep Arctic Ocean temperatures.

Main Methods:

• Analysis of observational data from the 1990s onwards.
• Temperature measurements in the Eurasian Basin between 2000 and 2600 m.
• Modeling the influence of ocean currents and geographic features (Fram Strait, Lomonosov Ridge) on heat distribution.

Main Results:

• Deep Arctic Ocean water in the Eurasian Basin is warming at 0.020°C/decade, exceeding geothermal heating.
• Warming in the deep Greenland Basin reduces its cooling effect on the Eurasian Basin via the Fram Strait.
• The Lomonosov Ridge impedes warming signal propagation, resulting in slower warming (0.003°C/decade) in the deep Amerasian Basin.

Conclusions:

• Climate change, particularly warming in the deep Greenland Basin, is a significant driver of deep Arctic Ocean warming.
• Geothermal heating alone cannot explain the observed warming rates.
• Deep Greenland Basin warming has discernible impacts on the broader deep Arctic Ocean ecosystem.