AFP: Brief but vicious Arctic storms known as polar lows are likely to become much less frequent as global warming intensifies, scientists in Britain determined on Wednesday. Polar lows brew in ice-free high latitudes in the North Atlantic in winter and can swiftly become a hazard for shipping and oil rigs. The number of these storms averaged 36 per season in the 20th century, climatologists at the University of Reading said. By 2100, this tally would fall to between 17 and …