Climate change: European team to drill for 'oldest ice' in Antarctica

Image copyrightLaurent AUGUSTIN/CNRSImage caption

图片copyrightLaurent AUGUSTIN / CNRSImage标题

The original EPICA project drilled an 800,000-year-old ice core between 1996 and 2005

最初的EPICA项目在1996年至2005年间钻了一个有80年历史的冰芯

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A European consortium will head to Antarctica in December to begin the process of drilling deep into the continent's eastern ice sheet.

欧洲财团将前往南极洲12月开始深入大陆东部冰盖的过程。

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Scientists hope this can lead them to an explanation for why Earth's ice ages flipped in frequency in the deep past.

科学家们希望这能引导他们解释为什么地球的冰河时代在过去的频率上会频繁翻转。

Although it might seem at first glance to be a rather esoteric quest, researchers say it bears down directly on the question of how much the world is likely to warm in the centuries ahead.

虽然看起来似乎乍一看研究人员说，这是一个相当深奥的探索，它直接关系到未来几个世界世界可能会变暖多少的问题。

“Something happened about 900,000 years ago. The ice age cycles changed from every 40,000 years or so, to every 100,000 years; and we don't know why,” Dr Catherine Ritz from the Institute of Environmental Geosciences in Grenoble, France, told BBC News.

“大约90万年前发生了一些事情。冰河时代周期从每4万年左右变为每100,00年0年;我们不知道为什么，”法国格勒诺布尔环境地球科学研究所的Catherine Ritz博士告诉BBC新闻。

“And it's rather important, because if we want to forecast what will happen to the climate in the future, with the increase in greenhouse gases, then we will have to use models, and these models will be calibrated on what happened in the past.”

“这很重要，因为如果我们想要的话为了预测未来气候将会发生什么，随着温室气体的增加，我们将不得不使用模型，这些模型将根据过去的情况进行校准。”

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It will be on a high ridge about 40km southwest from the Franco-Italian research station known as Dome Concordia. Already, the spot has been dubbed “Little Dome C”.

它将在一个高山脊上距离法国 - 意大利研究站Dome Concordia西南40公里。这个地方已经被称为“小圆顶C”。

Fourteen institutions from 10 countries will participate in what's referred to as the Beyond-EPICA project.

来自10个国家的14个机构将参与所提到的作为Beyond-EPICA项目。

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The expected total €30m (£26m) cost will be met out of the European Union's science budget, Horizon 2020.

期待的将达到3000万欧元（2600万英镑）的成本欧洲联盟的科学预算，地平线2020.

Image copyrightR.Mulvaney/BASImage caption Each bubble is a little time capsule recording the ancient atmosphere's contents How do ice cores record the climate of the past？

图片copyrightR.Mulvaney / BASImage标题每个气泡都是一个时间胶囊记录古代大气的内容冰芯如何记录气候过去？

The ice in Antarctica is made up of snows that fell on the continent over millions of years.

南极冰层是由数百万年来落在大陆上的雪组成的。

As this ice was pressed down, it captured bubbles of air. These little gas pockets are a direct snapshot of the atmosphere.

这冰被压下来，它捕获了空气泡。这些小气袋是大气层的直接快照。

Scientists can read off the levels of carbon dioxide and other heat-trapping components such as methane, for example.

科学家可以读取二氧化碳和其他吸热成分（如甲烷）的水平。

Analysing the atoms in the water-ice molecules encasing the gases also gives an indication of the temperatures that persisted at the time of precipitation.

分析包裹气体的水冰分子中的原子也可以指示降水时持续存在的温度。

Currently, the oldest, continuous ice core ever drilled comes from the previous effort at Dome C called the European Project for Ice Coring in Antarctica (EPICA).

目前，有史以来最古老的连续冰芯来自于Dome C先前在南极洲进行的欧洲冰心核项目（EPICA）。

This ran from 1996 to 2004, and pulled up a 10cm-wide cylinder of ice that was 2,774m long.

1996年至2004年，并拉起一个长达2,774米的10厘米宽的冰柱。

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Media captionDr Rob Mulvaney: “We need to understand why we're now living in a 100,000-year world”What did this previous ice core reveal？

媒体标题Rob Robvaney：“我们需要了解为什么我们现在生活在一个拥有10万年历史的世界”这个以前的冰芯揭示了吗？

The old EPICA core contained an 800,000-year record of temperatures and atmospheric carbon dioxide.

旧的EPICA核心包含了80万年的温度和大气二氧化碳记录。

These markers were seen to move in lock-step. Whenever the Earth went into an ice age and temperatures fell, the concentration of greenhouse gases in the atmosphere would also decline. And when the climate warmed back up again, the CO2 rose rise in parallel.

看到这些标记在锁定步骤中移动。每当地球进入冰河时代，气温下降，大气中的温室气体浓度也会下降。当气候再次升温时，二氧化碳同时上升。

These cycles occurred roughly every 100,000 years in the EPICA core - a phasing that is most likely linked to slight shifts in the eccentricity of Earth's orbit (a larger or smaller ellipse) around the Sun.

这些周期在EPICA核心大约每10万年发生一次 - 分阶段很可能与轻微相关地球轨道偏心的变化（一个更大或更小的椭圆）a太阳爆发了。{/ p>

But it is recognised from an alternative record of past climate, which has been deciphered from ocean sediments, that deeper back in time the ice age cycle was much shorter - at about every 41,000 years.

但是从过去的气候的另一个记录中可以看出，这个记录已经从海洋沉积物中破译，冰河时代周期的时间更短 - 大约每41，000年。

That is a period probably dominated by the way the Earth tilts back and forth on its axis. But why the switch occurred, no-one is really sure.

这个时期可能是地球在其轴上来回倾斜的方式所主导的。但为什么转换发生，没有人确定。

Image caption The previous ice core showed temperature and carbon dioxide moving in lock-step What could be the reason for the switch？

图片标题前一个冰芯显示温度和二氧化碳在锁定步骤中移动可能是切换的原因？

The orbital quirks described above change how much of the Sun's energy reaches the Earth, and it accounts for variations in global temperatures in the order of 1.5 degrees Celsius.

上述轨道怪癖改变了太阳能量到达地球的程度，它解释了全球温度变化大约1.5摄氏度。

But ice ages - from their minimum to their maximum states - involve variations of six degrees. This means there have to have been amplification processes in play.

但冰的年龄 - 从最小到最大状态 - 涉及六度的变化。这意味着必须有放大过程。

Differences in the mix and level of greenhouse gases in the atmosphere will no doubt be a part of the story, and the Beyond-EPICA ice core, if it it can reach back to 1.5 million years ago, will expose this particular contribution. There are certain to be additional factors, however.

大气中温室气体混合和水平的差异无疑将成为故事的一部分，而且超越-EPICA冰芯，如果它可以追溯到150万年前，将揭示这一特殊贡献。然而，肯定会有其他因素。

“In my personal opinion, the best candidate is an internal mechanism in the climate system which has to do with changes in the ice volume on Earth,” said Prof Olaf Eisen, the Beyond-EPICA project coordinator from Germany's Alfred-Wegener-Institute.

“我个人认为，最佳候选人是气候系统内部机制，与冰量的变化有关在地球上，”来自德国Alfred-Wegener研究所的Beyond-EPICA项目协调员Olaf Eisen教授说。

If you change ice volume, you also change sea-level and ocean circulation. But something happened in what we call the Middle Pleistocene Transition.

如果你改变冰量，你也会改变海平面和在我们所谓的中更新世过渡期间发生了一些事情。

“The drivers behind the MPT are still under debate and touch on the basic understanding of the climate system.”

“MPT背后的驱动因素仍然存在争议，触及对气候系统的基本认识。”

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Media captionSurvey work included building a radar map of the bedrock under Little Dome CHas Europe chosen the right location？

媒体标题调查工作包括构建在Little Dome CHas Europe下选择合适位置的基岩雷达图？

The site is helped enormously in terms of logistics by being close to an existing research base, but Little Dome C's selection was only approved after three years of careful survey work.

通过接近现有的研究基地，该网站在物流方面得到了极大的帮助，但Little Dome C的选择只是经过三年的仔细调查工作后获得批准。

Teams dragged radar instruments back and forth across the ice to map the layers below. They even sank test boreholes to work out how warm it was likely to be at the base of the ice sheet.

小组在冰上来回拖动雷达仪器，以绘制下面的图层。他们甚至沉没测试钻孔，以确定它在冰盖底部的温度。

One of the complexities is that heat coming up from the bedrock will melt away the bottom-most and oldest layers of ice. This is a very real danger the deeper the drilling goes, as the coldest temperatures are always found closest to the surface of the ice sheet.

其中一个复杂因素是来自基岩的热量将会融化远离最底层和最古老的冰层。钻探越深，这是一个非常现实的危险，因为最冷的温度总是最接近冰盖表面。

“The core will be in 4m lengths when it comes up,” explained Dr Rob Mulvaney from the British Antarctic Survey. We'll cut it into 1m sections at Little Dome C and then move them to Concordia station itself.

“当核心长度为4米时它出现了，”英国南极调查局的Rob Mulvaney博士解释道。 我们将把它切成1m部分在Little Dome C，然后将它们移到Concordia站。

“At the station we'll cut the sections in half, lengthways. One half we'll leave in Antarctica as a long-term archive (we won't have to pay freezer costs!), and the other half will come back to Europe for analysis.”

“在车站，我们会将部分切成两半，纵向。一半我们将作为长期存档留在南极洲（我们不必支付冷冻费！），另一半将返回欧洲进行分析。”

Image copyrightR.Mulvaney/BASImage caption In their radar survey at Little Dome C, the field team drove 2,500km

图片copyrightR.Mulvaney / BASImage标题在Little Dome C的雷达测量中，现场团队开了2,500公里