About 3 billion people live within 100 miles （160km) of the sea, a number that could doubl

About 3 billion people live within 100 miles (160km) of the sea, a number that could double in the next decade as humans flock to coastal cities. The oceans produce $3 trillion of goods and services each year and untold【C1】______for the Earths ecology. Life could not exist【C2】______these vast water reserves—and, if anything, they are becoming even more important to humans than before. Mining is about to begin under the seabed in the high seas. New summer shipping lanes are opening【C3】______the Arctic Ocean. The genetic resources of marine life promise a big【C4】______: the number of patents has been rising at 12% a year. But these developments are【C5】______compared with vaster forces reshaping the Earth, both on land and at sea It has long been clear that people are damaging the oceans—【C6】______the melting of the Arctic ice in summer and the death of marine lives. Now, the【C7】______of that damage are starting to be felt onshore. Thailand provides a【C8】______example. In the 1990s it cleared coastal plants to set up fish farms. Ocean storm surges in 2011, no longer【C9】______by the plants, rushed in to【C10】______the countrys industrial heartland, causing billions of dollars of damage. More【C11】______is the global mismanagement of fish stocks. About 3 billion people get a fifth of their protein from fish, making it a more important protein source than beef.【C12】______a vicious cycle has developed as fish stocks decline and fishermen【C13】______to grab what they can of the remainder.【C14】______the Food and Agriculture Organization, a third of fish stocks in the oceans are over-exploited. People could be eating much better, were fishing stocks【C15】______managed. The forests are often called the lungs of the Earth, but the description better fits the oceans. They produce half the worlds【C16】______of oxygen. At the moment, the oceans are moderating the【C17】______of global warming— though that may not【C18】______This cannot be good news,【C19】______scientists are still debating the likely consequences.【C20】______, the decades of damage imposed on the oceans are now damaging the environment on land.

【C1】

A．value

B．secret

C．harm

D．possibility