Increasingly, as a result of the greenhouse effect, winds often carry a lot of moisture with them, evaporated from the surface of overheated tropical oceans. When this moisture is carried in clouds to higher latitudes it precipitates out, as increasing rain during the spring and autumn and as more snow and ice during winter. Thus winters get longer and colder.
In 1987 a severe cold wave swept across Europe paralyzing transportation, closing schools, businesses and governmental offices, causing more than 264 deaths, raising oil prices and causing a large number of accidents. In 1993 concerns were expressed that winter would place 4.25 million lives at risk in war-torn Yugoslavia, including 2.8 million in Bosnia. A similar situation had been averted the previous winter by massive inflows of humanitarian aid. Also in 1993, a cold spell raised concern in France about the condition of an estimated 10,000 homeless. In 1994 it was estimated that winter cold claimed 50,000 lives each year in the UK, of which over half resulted from heart attacks and strokes due to the tendency of blood to become more concentrated with cold and thus to clot more readily. In the USA the 1994 winter was expected to cost the insurance industry some US$1 billion for damage caused by storms.