Global warming may end 'polar' storms

READING, England, Sept. 15 (UPI) -- Climate change, expected to increase extreme weather events around the world, will make one particular kind of event rarer, U.K. researchers say.

Scientists at the University of Reading say climate simulations show severe North Atlantic storms known as "polar lows" and resembling arctic hurricanes may decrease by as much as 50 percent by the end of this century, a report in the journal Nature says.

Polar lows are small-scale but severe winter storms that threaten offshore human activities in the North Atlantic region.

Reading researchers Matthias Zahn and Hans von Storch studied the formation of polar lows in a series of regional climate simulations corresponding to different possible future climates.

Assuming a range of elevated atmospheric greenhouse gas concentrations, they found a significantly lower frequency of polar lows, compared with a late-20th-century simulation.

A greater increase in temperature in the lower atmosphere than at the surface of the North Atlantic would decrease the vertical temperature gradient, stabilizing the atmosphere and hindering the formation or intensification of polar lows, Zahn and von Storch say.