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. PAI's rankings of per-capita emissions, released for Earth Day 2000, are based on the most recent data available from the United Nations and the U.S. government. The accord calls for the U.S. to reduce greenhouse gases to 7 percent below what they were in 1990. Europe and Japan would make cuts of 8 percent and 7 percent below 1990 amounts.