Ice Cores Reveal Green Arctic

Ice Cores Reveal Green Arctic
The Arctic wasn't always covered in ice. Samples of sediment layers beneath a frozen lake show this region used to be a lot warmer—and may thaw out again in the future. The work is in the journalScience. [Julie Brigham-Grette et al., Pliocene Warmth, Polar Amplification, and Stepped Pleistocene Cooling Recorded in NE Arctic Russia]
北极并非一直是被冰层覆盖。一个冰湖下的矿物层样本表明，这个地区以前曾温暖得多——并且在未来会解冻。这项工作发表在 the journalScience. [Julie Brigham-Grette et al., Pliocene Warmth, Polar Amplification, and Stepped Pleistocene Cooling Recorded in NE Arctic Russia]
El'gygytgyn, a Russian lake 100 kilometers north of the Arctic Circle, contains layers of sediment that date back to the lake's formation 3.6 million years ago. Analyses of sediment cores have revealed that back then summers reached about 15 to 16 degrees Celsius, a good 8 degrees warmer than modern Arctic summers. These warm temperatures, which supported plants like Douglas fir and hemlock, lasted until about 2.2 million years ago.
El'gygytgyn, 一个俄罗斯湖，距离北极圈100千米，含有360万年前湖的形成时期的矿物样本。矿物分析表明，那时候的夏天温度达到15-16摄氏度。比现在的北极高8度。这种温度，使得像 Douglas fir 和 hemlock这样的植物，一直存活到220万年前。
Using a sediment core as a detailed history of climate change, scientists can see how the forested Arctic gradually became covered in ice and snow. These changes help us understand details about the development of Ice Ages. In addition, the sediment comes from a window of time during the Pliocene Epoch, when greenhouse gas levels were only slightly higher than they are today. Such sensitivity to small carbon dioxide changes hint at a warm Arctic future.
使用地质核研究气候变化历史，科学家们可以看见，森林覆盖的北极如何逐渐被冰雪覆盖。这些改变帮助我们理解关于冰河时期发展的细节。另外，矿物来自于上新世，这时期温室气体水平只比今天高一点。这种对二氧化碳的敏感性，预示着北极温暖的前景。