Recent studies have identified four major global environmental risks: (36) rain, ozone depletion, (37) and the greenhouse effect. On the whole, thanks to technological changes, people now (38) to move toward warmer regions in North America and Europe. Climate warming will probably be a (39) to Alaska, which is America’s (40) productive state in Gross National Product (GNP) per square mile. Studies of the (41) of global warming on the United States and other developed regions find that the most vulnerable areas are those (42) on undamaged ecosystems -- on naturally (43) rainfall, run-off and temperatures, and the extreme of these variables. Agriculture, forestry and coastal activities fall into this category. (44) . Intensive-care units pf hospitals, communications, heavy manufacturing and microelectronics are among the sectors likely to be unaffected by climate change. In selecting whether to set up in, say , Hong Kong or in Warsaw, few businesses will consider temperature a weighty factor. (45) About 3% of American GNP originates in climate-sensitive sectors such as farming and forestry. Another 10% comes from sectors only modestly sensitive -- energy, water systems, property and construction. (46) .