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BBC英语新闻:二氧化碳排放量增多竟有益处

比目鱼 于2016-05-11发布 l 已有人浏览
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大家都有一个科学共识,那就是二氧化碳排放量增多导致全球变暖以及气候变化。一项新研究表明,人类活动引起的二氧化碳水平也有积极影响,即它会大大促进植物生长。
    小E英语欢迎您,请点击播放按钮开始播放……

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There is a general scientific consensus that growing carbon dioxide emissions are contributing to global warming and climate change. A new study suggests that carbon dioxide levels caused by human activity have also had a positive effect. They’ ve led to a massive increase in plant growth. Our environment analyst Roger Harrabin explains.

Today’s study in the journal Nature Climate Change has been compiled by a team from eight countries. Using satellite data, they calculate that between a quarter and a half of the earth’s vegetated land has become greener over the thirty-three years since the records began. That’s equivalent to more than four billion giant sequoia trees, the biggest trees on the planet. The scientists say the rising global temperature has helped fuel the plant boom along with more nitrogen in the environment and shifts in land management. But they estimate that seventy percent of the change has been caused by plants absorbing more of our emissions of carbon dioxide because CO2 is a plant fertilizer. This is good news because as plants soak up the carbon, they are slowing somewhat the pace of climate change by keeping the carbon out of the atmosphere. Some people skeptical about the dangers of the global warming say this proves there is less need to worry. But the paper’s lead author from Boston University says the benefit from greening is outweighed by other climate effects, melting sea ice, rising temperatures, ocean acidification and more.

If we tally the beneficial and the harmful effects of having too much carbon dioxide in the air, the net effect is largely negative.

And there is another warning, the authors say if the governments don’t cut emissions as they agreed, there will come a point where the climate warms so much that the capacity of plants to soak up some of our CO2 is overwhelmed by the carbon that will be released from soils drying up in the heat. No one knows when that moment will happen.

The BBC’s environment analyst Roger Harrabin.Now do you have a fondness for red and black? You may want to rethink that. A study in the US has found the bedbugs have a strong preference for some colours. The BBC health editor Michelle Roberts came in to explain the scientists’ findings.

They got lots of these adult bedbugs and they put them in a dish. And with little triangles of tent-like card of different colours, they found that the bedbugs seem to gravitate towards red or black whereas the ones that they really didn’t like were the yellow and the green.Any indication why they prefer certain colours?It’s difficult to know.

 
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