Climatic Change and Ice Extent on the Sea.
A review of the effect of the polar ice pack on world climate. About 10 percent of the ocean area in the northern hemissphere and 13 percent in the southern hemisphere is covered in winter by floating ice of variable extent. As the ice pack recedes, storm tracks go farther north and midlatitude rainfall patterns shift eastward. Apparently changes in solar radiation intensity in Antarctica result in changes in the global circulation, which, in turn, affect the extent of the Arctic ice, especially during the northern summer. From 1890 to 1940 the mean thickness of Arctic ice decreased by about 30 percent, and the area covered decreased by 10 to 15 percent; the intensity of the entire global circulation increased markedly and the planet became warmer (10 degrees warmer in the Norwegian Sea). This change has been reversed since 1940. Global circulation seems in general to be strongest when the extent of Antarctic ice is greatest. 22 pp. Bibliog. (A shortened version of P-3801.)