More Fresh Water in the Arctic Ocean

© Eugene S. Takle, 2002

Global warming is not expected to be uniform over the planet but instead will warm polar regions more than tropics. Increased ice melt due to this enhanced high-latitude warming, coupled with more precipitation to accompany the higher mean temperature, will provide more fresh water in Arctic regions. This fresh water, being less dense than saline water at the same temperature, will suppress the thermohaline circulation in the Arctic region. It is the sinking saline water of the thermohaline circulation in the Arctic that allows northward-flowing surface water in the North Atlantic (extension of the Gulf Stream) to move heat northward and provide Europe with mild temperatures, considering how far north it lies. So reduction in the thermohaline circulation will tend to suppress this warming of Europe.

Peterson et al (2002) report that river discharges from the six largest Eurasian rivers to the Arctic Ocean increased by 7% from 1936 to 1999, annually putting 128 cubic kilometers more water into the Arctic basin than when measurements began. This increased volume of fresh water in the Artic Ocean has important consequences for ocean global heat transport and hence for global temperatures.

Reference

Peterson, R. J., and Coauthors, 2002: Increasing river discharge to the Arctic Ocean. Science 298, 2171-2173.