Iceland, so named to discourage conquest by expanding empires, is not ice-covered like Greenland and parts of Siberia, even though it is nearly on the Arctic Circle. The average winter temperature of...

Iceland, so named to discourage conquest by expanding empires, is not ice-covered like Greenland and parts of Siberia, even though it is nearly on the Arctic Circle. The average winter temperature of Iceland is considerably higher than the temperatures of regions at the same latitude in eastern Greenland and central Siberia. Why is this so?