In three of the past five years, however, the Arctic has been frigid enough for clouds to form. Strangely enough, many scientists believe this cooling is due to global warming. Most scientists believe that Earth's surface is getting warmer because greenhouse gases, primarily carbon dioxide, are trapping heat in the lower atmosphere. If the heat stays near the surface, it is not getting up to these higher levels, making it cold enough for clouds to form. The Scott Polar Research Institute reports that for fifth winter in the last seven years, a huge tongue of shelf ice had failed to form in the Greenland sea.
Arctic ice is both thinning and dwindling.
The Gulf Stream flows north from the Caribbean, keeping Britain at least 15 degrees F warmer than expected at its latitude. The Gulf Stream merges with the north Atlantic current, and the encounter of this giant, warm surface river with the Arctic winter ice helps to keep the ocean swirling. Ice is fresh water - so the sea that remains is increasingly cold, salty and dense. The ranking is part of a new PAI report. In 1996 the United States, with just 4.7 percent of the world's people, contributed more than 22 percent of all global emissions of carbon dioxide from fossil fuel combustion and cement manufacture.