Polar bears hunt seals from sea ice, but could drown if forced to swim long distances in open water. Satellite photos【B1】______b

Polar bears hunt seals from sea ice, but could drown if forced to swim long distances in open water. Satellite photos(36)released by America’s space agency, NASA, illustrate the fearful(37)threat to such bears. An image shows the amount of Arctic Sea ice in 1979. Another image shows the record(38)minimum set this year on September 16th. The shrinkage is(39)equivalent to an area greater than Texas, an impossible distance for even the(40)mightiest polar bear to swim.
    Scientists say fossil fuels are increasing carbon(41)emissions in the atmosphere. This not only warms the oceans, but threatens biodiversity in cold and warm waters alike. As the carbon dioxide is increased in the atmosphere, a high(42)proportion, about 40 percent of that, goes back into the ocean, and so it’s increasing the acid(43)content of the ocean and that’s threatening fisheries.
    Scientists at a recent conference at Columbia University’s Earth Institute said(44)less ice is likely to draw some shipping away from the Panama Canal. This is because a northern route, though still risky, reduces the distance between Europe and Asia by about 6,500 kilometers.
    Countries bordering the Arctic are not the only ones with interests there.(45)There certainly will be interest in the Arctic from nations that don’t touch physically on the Arctic; that’s very clear for natural resources, for fishing, for a variety of reasons. Energy supplies are among those reasons. Scientists say more open water in the Arctic means more gas from water and extreme weather elsewhere.
    The Arctic is far from most of the world’s population.(46)However, scientists caution that distance is no guarantee people will be spared the effects of warming in the planet’s northernmost regions.