A Sea of Troubles 海洋的阅读文章.pdf

A Sea of Troubles Man is attacking the oceans. They will beat him if he does not take care. NOT much is known about the sea, it is said; the surface of Mars is better mapped. But 2,000 holes have now been drilled in the bottom, 100,000 photographs have been taken, satellites monitor the five oceans and everywhere floats fitted with instruments rise and fall like moving yo-yos. Quite a lot is known, and very little is comforting. The worries begin at the surface, where an atmosphere newly laden with man-made carbon dioxide interacts with the sea water. The sea has thus become more acidic, making life difficult, if not impossible, for marine organisms with calcium-carbonate shells or skeletons. Worse, you may disturb entire ecosystem. That is also what acidification does to coral reefs, especially if they are already suffering from too much fishing, too much heating or pollution. Many are, and most are therefore gravely damaged. Some scientists believe that coral reefs, home to a quarter of all marine species, may virtually disappear within a few decades. That would be the end of the rainforests of the seas. Carbon dioxide affects the sea in other ways, too, notably through global warming. The oceans expand as they warm up. They are also enlarged by melting glaciers, ice caps and ice sheets: Greenland’s ice is on track to melt completely, which will eventually raise the sea level by about seven meters (23ft). Even by the end of this century, the level may well have risen by 80cm, perhaps by much more. For the 630m people who live within 10km (six miles) of the sea, this is serious. Countries like Bangladesh, with 150 million inhabitants, will be inundated. Even people living far inl