一本教會你“做對”題的6級閱讀書 day20 passage1
Passage 1 Melting Arctic: Forget Polar Bears, Worry About Humans
北極熊在哭泣 《新科學(xué)家》
[00:04]Melting Arctic: Forget polar bears, worry about humans
[00:10]The fate of polar bears
[00:13]Patient "still hunting" at the edge of an ice floe
[00:17]is the polar bear's number one technique for catching seals.
[00:23]A bear may sit or stand like this for an hour or more, utterly still but alert,
[00:30]until a seal surfaces for air. Then there is a flurry of bloody action.
[00:37]Not long ago, tourists on ships passing through this region would amuse themselves by shooting polar bears.
[00:45]But since the 1970s, the Norwegian government has been protecting bears here with such seriousness
[00:52]that locals joke: "You are better off shooting a man than a bear -
[00:57]the authorities will investigate you less thoroughly."
[01:01]In 2008, the United States Geological Survey (USGS) combined models of the future state
[01:10]of the Arctic ice with what was known about the life of bears.
[01:16]Polar bears are utterly dependent on ice as a platform to hunt seals.
[01:22]As the Arctic summer ice disappears,
[01:26]the hunting period is growing shorter and breeding success is falling.
[01:33]The bleak conclusion of one USGS model was "extinction by 2050" for the bears of Svalbard.
[01:42]A few areas did better, but only in the frozen channels among the northerly Canadian islands
[01:49]might bears survive as rulers of the ice until the end of the century.
[01:54]These are grim forecasts but they are also conservative because they are based on models
[02:00]that aren't keeping up with the terrible speed of the ice's collapse.
[02:07]A great transformation
[02:09]In the far north, the biggest and fastest change to our planet ever caused by human activity is under way.
[02:18]As the Earth warms, more and more of the frozen Arctic seas are melting away.
[02:24]Each winter, the ice grows until it covers an area more than one and a half times as great as the US.
[02:32]In summer, that ice used to melt to half the winter area. Now, after a catastrophic collapse in 2007,
[02:42]close to two-thirds of the ice is vanishing. Compared with a decade earlier,
[02:48]the Arctic is losing an extra area of ice each summer six times as large as California.
[02:55]Estimates of when the ice will completely disappear each summer now range from 2013 to 2050.
[03:04]A great transformation is under way.
[03:08]The change from ice to water is an end for many familiar creatures ,but
[03:14]in a wider sense, it is not an end.
[03:19]The Arctic is being reborn as a sea that is more similar to southerly seas.
[03:26]Whales, fish, birds and plankton that are more at home in warmer waters are already invading the Arctic.
[03:37]This is the beginning of a new Arctic ecosystem that is forming as the old Arctic dies.
[03:45]In purely biological terms, the new Arctic will be more productive than the old,
[03:52]because there is more water, open to sunlight for longer,
[03:56]with more plankton growing in it, and more food supports more life.
[04:02]The first signs are already there. After the sudden collapse of the sea ice in 2007,
[04:10]a satellite-borne sensor, measuring the water's "greenness",
[04:14]showed that the total productivity of the Arctic seas leapt by 40 per cent. That is a big increase.
[04:24]Louis Fortier, a marine biologist at Laval University in Quebec, Canada,
[04:30]explained it like this: "If you look at it simply from the point of view of biological productivity,
[04:38]that will increase as the ice disappears. It's just that the life there,
[04:43]the specialists which people are all fond of, like the polar bear and some other species
[04:49]which we have in our unconscious mind, are going to get into trouble."
[05:01]Fruitless efforts to combat climate change
[05:05]For too long, too many fruitless efforts to combat climate change have been billed as "Saving the Planet".
[05:15]Right now, in the last week or two before the climate negotiations at Copenhagen,
[05:22]there are few signs of dramatic action. Perhaps that is because the message is wrong.
[05:29]As the changes in the Arctic show, the planet continues. Species come and species go.
[05:38]The planet does not need saving, even from human.
[05:43]The urgent need to reduce greenhouse gas emissions is portrayed as simple self-interest.
[05:51]People focus on the coming losses of agricultural production, the droughts,
[05:57]the mass migrations and political instability that will follow rapid climate change.
[06:04]Political will might be better stiffened by listening to generals rather than to environmentalists.
[06:12]As a former head of the US Central Command, Anthony Zinni, explained,
[06:18]"if we don't pay the price to reduce greenhouse gas emissions today,
[06:23]we will pay the price later in military terms".
[06:34]The Arctic's revenge
[06:37]Then turn again to the far north, not to worry about bears,
[06:42]but in fear of the Arctic's revenge. For millions of years,
[06:47]the brilliant white ice around the North Pole has reflected the summer sunlight back into space,
[06:54]helping cool the planet. As the ice turns sea dark and soaks up the sun,
[07:01]global warming will really take off. Already the signs are there:
[07:06]in areas where the sea ice has gone, summer temperatures
[07:10]are between 3 °C and 5 °C higher than the average of the previous 20 years.
[07:20]As the differences in temperature between the Arctic and the equator lessen,
[07:25]the weather and rain patterns all over the northern hemisphere are altering.
[07:31]As the new Arctic sea heats up, a pool of warm air is spreading across the nearby lands.
[07:39]Shrubs and trees are creeping north across the tundra Dark vegetation
[07:46]soaks up more heat and the warming gains pace.
[07:51]Elsewhere, the top layer of permafrost is rotting away.
[07:56]It contains enough carbon to more than double the carbon dioxide in the atmosphere,
[08:02]taking humans back to an era when temperatures were more than 7 °C higher than they are now.
[08:12]Of course, the carbon will not be released all at once. Instead,
[08:17]the Arctic will favour a long, slow revenge, spread over hundreds of years.
[08:24]As well as this, with the same painful slowness, the melting ice caps
[08:30]will make sea levels rise perhaps a metre this century and then every century for a thousand years.
[08:38]Once these changes really get going, they will be unstoppable.
[08:44]If these thoughts don't make people wake up, then people are really in deep trouble.
[08:50]Only blind abandonment to self-destructive materialism is left with humans.
