【英语时差8,16】人类活动导致企鹅数量减少（上）（在线收听）

Like the canaries that used to be brought into coal mines as early warning signals for toxic gases like methane, the world’s penguins are sounding an alarm of potentially disastrous ocean changes. Of the seventeen species of penguins, twelve are declining rapidly in number and are listed as endangered or threatened. A study published in 2008 by a Professor of Conservation Biology at the University of Washington links this widespread decline in penguin numbers, in large part, to human activity. One cause is the rising ocean temperatures and increasingly erratic temperature and climate patterns. In the Antarctic Peninsula, where many penguins breed, temperatures are rising five times faster than the average rate of global warming, and sea ice covers forty-percent less area off the peninsula than it did twenty-six years ago.