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科学美国人60秒 SSS 二氧化碳浓度回到过去水平

时间:2017-07-04 08:16:03

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(单词翻译)

Climate 420 Million Years Ago Poised1 for Comeback 二氧化碳浓度回到过去水平

“We’re hearing a lot of the arguments against action on reducing CO2being based on, ‘well CO2 was higher in the past, so we don’t have to worry about it.’

我们听到很多关于反对减少CO2的争论,”CO2含量本来就很高,我们不用担心.”

Gavin Foster, a geochemist at the University of Southampton. But Foster says that’s a flawed argument. For starters, just how far back in time do you have to look to find CO2 concentrations like what we expect to see in the future, and does it even make sense to compare the levels now and then?

加文·福斯特,是南安普顿大学的地球化学家。但是福斯特表示,这是一个有缺陷的观点.首先,那得追溯到过去什么时候,二氧化碳的浓度才和现在一样高,其次, 将现在二氧化碳的浓度和当时相比有什么意义呢?

To answer these questions, Foster and his colleagues reconstructed the history of atmospheric2 carbon dioxide for the last 420 million years. They compiled roughly 1,500 estimates of CO2 concentrations from 112 previous studies. When the researchers combined these data, they found that atmospheric carbon dioxide went up and down over time, but that, in general, it gradually declined from almost 3,000 parts per million down to less than 300 parts per million before humans started burning fossil fuels.

为了回答这些问题,福斯特和同事们重构了过去4.2亿万年前大气中二氧化碳的历史.他们对之前关于112个研究中关于二氧化碳浓度的近1500种估计进行了编纂. 研究人员综合这些数据,他们发现,随着时间的推移,大气中的二氧化碳含量也在上下起伏,但是总体而言,在人类开始燃烧矿物燃料之前,大气中的二氧化碳含量从3000ppm下降到了不足300ppm.

However, we have already started to reverse that trend. If we continue on a business-as-usual scenario3, by the middle of this century, CO2 could reach levels not seen in 50 million years, according to Foster’s reconstruction4. That’s long before humans evolved, back when the climate was much warmer and there were no large ice sheets at the poles. If we continue on that trajectory5, by the year 2250, concentrations could approach what they were in the Triassic, 200 million years ago, when dinosaurs6 roamed the Earth.

但是,现在我们已经开始扭转这一趋势。如果我们继续按照“一切如常”,根据福斯特的数据,到本世纪中叶,二氧化碳的浓度将会突破过去5千万年新高。而在5千万年前,气候还非常的温暖,地球的两极还没有冰原。如果我们继续这种轨迹,那么在2250年,大气中二氧化碳的浓度将会达到2亿年三叠纪时的水平,而那时恐龙还在地球上漫步。

But greenhouse gases aren’t the only factor impacting Earth’s climate. The sun also plays a major role. It’s grown brighter over time, offsetting7 most of the cooling related to dropping CO2 levels, Foster’s team found. And that fact has important implications for modern climate change. Because while we’re headed toward a world with CO2 levels similar to what they were in the distant geologic8 past, it won’t just be like rewinding the clock.

但是温室气体并不是影响地球气候的唯一因素。太阳也起着重要的作用。福斯特团队发现,随着时间的推移,太阳的亮度增加,这会抵消降低二氧化碳含量的多数冷却成分。这一事实对于现代气候的变化有着重要的意义。因为未来的世界二氧化碳的水平和遥远的地质时代的水平相似,这并不像时间倒流这么简单。

“So, because the sun is now brighter than it was 200 million years ago, or 400 million years ago, that radiative forcing from CO2 in the future is going to be that much more potent9. And that, we thought, was quite a strong message that hadn’t been noted10 before.”

现在与2亿年前相比,或者4亿年前相比,现在的太阳亮度增加了,这会使未来二氧化碳的辐射强度更加强大。我们认为,这是我们之前没有注意到一个强有力的信息。

The findings are published in the journal Nature Communications.

该研究结果发表在《自然通讯》杂志上。

Foster stresses that this isn’t a vision of what will be, but what could be. “It’s more of cautionary note that, in the absence of any action, we will be entering a world quite rapidly—in the next 150 years—where the climate is receiving a magnitude of forcing that, as far as we know, it hasn’t received for 420 million years…it’s outside the bounds at which the Earth is normally functioning. Doesn’t sound like a good place to be to me.”

福斯特强调,这并不是一个愿景,而是未来会实现的。“这更多的是警示,如果不采取任何的行动,在未来150年,我们将迅速进入一个世界——据我们所知,未来气候将达到强迫级别,而在4.2亿年前,也未达到这种情况。表面看来地球运行正常,但是似乎对于我来说,不再像一个完美的地方了。”


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1 poised SlhzBU     
a.摆好姿势不动的
参考例句:
  • The hawk poised in mid-air ready to swoop. 老鹰在半空中盘旋,准备俯冲。
  • Tina was tense, her hand poised over the telephone. 蒂娜心情紧张,手悬在电话机上。
2 atmospheric 6eayR     
adj.大气的,空气的;大气层的;大气所引起的
参考例句:
  • Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
  • Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。
3 scenario lZoxm     
n.剧本,脚本;概要
参考例句:
  • But the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
  • This is a totally different scenario.这是完全不同的剧本。
4 reconstruction 3U6xb     
n.重建,再现,复原
参考例句:
  • The country faces a huge task of national reconstruction following the war.战后,该国面临着重建家园的艰巨任务。
  • In the period of reconstruction,technique decides everything.在重建时期,技术决定一切。
5 trajectory fJ1z1     
n.弹道,轨道
参考例句:
  • It is not difficult to sketch the subsequent trajectory.很容易描绘出它们最终的轨迹。
  • The path followed by a projectile is called its trajectory.抛物体所循的路径称为它的轨道。
6 dinosaurs 87f9c39b9e3f358174d58a584c2727b4     
n.恐龙( dinosaur的名词复数 );守旧落伍的人,过时落后的东西
参考例句:
  • The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
  • Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》
7 offsetting c005dfe34c894146c623d2dd18e54b55     
n.偏置法v.抵消( offset的现在分词 );补偿;(为了比较的目的而)把…并列(或并置);为(管道等)装支管
参考例句:
  • Dealers, having concluded a forward contract, should always hedge with an offsetting contract. 外汇经营商在签订了一项远期合同之后总是应进行套头交易签订一项相抵合同。 来自辞典例句
  • Where does Germany think offsetting shifts into greater external deficits might occur? 在德国看来,这么大的外部赤字应该转移到哪里? 来自互联网
8 geologic dg3x9     
adj.地质的
参考例句:
  • The Red Sea is a geologic continuation of the valley.红海就是一个峡谷在地质上的继续发展。
  • Delineation of channels is the first step of geologic evaluation.勾划河道的轮廓是地质解译的第一步。
9 potent C1uzk     
adj.强有力的,有权势的;有效力的
参考例句:
  • The medicine had a potent effect on your disease.这药物对你的病疗效很大。
  • We must account of his potent influence.我们必须考虑他的强有力的影响。
10 noted 5n4zXc     
adj.著名的,知名的
参考例句:
  • The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
  • Jim is noted for arriving late for work.吉姆上班迟到出了名。

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