地球冰川的消逝将改变你对过去50年的看法

地球冰川的消逝将改变你对过去50年的看法

New timelapse videos from satellites that have been monitoring Earth for decades have revealed the shocking reality of ice melting at accelerated speeds all over our planet.

几十年来一直在监测地球的卫星拍摄的最新时间间隔视频揭示了一个令人震惊的事实:地球上所有的冰都在加速融化。

The series focuses on glaciers and ice sheets in Alaska, Greenland and Antarctica, showing how, over the decades, most of the ice is retreating annually and not growing back.

该系列聚焦于阿拉斯加、格陵兰岛和南极洲的冰川和冰原，展示了在过去几十年里，大部分冰川每年都在退缩，而不是重新生长。

I think observational glaciology in terms of remote sensing is a very data-rich field now, compared to 1972, when you had a few images, says glaciologist Mark Fahnestock of the University of Alaska Fairbanks.

阿拉斯加费尔班克斯大学的冰川学家马克·法赫内斯托克说:“我认为，从遥感的角度来看，观测冰川学现在是一个数据非常丰富的领域。

So we are beginning to get a historical record of the speeds of glaciers, and so we can watch how rapidly that surface is lowering as things speed up, or where it's thickening.

“所以我们开始获得冰川速度的历史记录，这样我们就可以看到随着速度的加快，冰川表面下降的速度有多快，或者冰川在哪里变厚。”

Using Landsat images dating back to 1972 and continuing all the way up to this year for a total of nearly 48 years, Fahnestock created six-second timelapses of all the glaciers in Alaska and Yukon. While some of the ice masses grow over that time, most of them shrink quite shockingly.

Fahnestock使用的是1972年的Landsat图像，一直延续到今年，历时近48年，创造了阿拉斯加和育空地区所有冰川的6秒钟时间。虽然有些冰块在这段时间内不断增大，但大多数都缩小得相当惊人。

It is, according to scientists, a clear illustration of the havoc being wreaked by climate change. You see, for instance, the Columbia glacier remaining stable until about the mid-1980s, when it starts disintegrating and retreating into the Chugach Mountains. It's now one of the most rapidly changing glaciers in the world.

据科学家说，这是气候变化造成的严重破坏的一个清楚的例子。例如，你可以看到，哥伦比亚冰川在20世纪80年代中期之前一直保持稳定，直到它开始瓦解并退缩到丘加奇山脉。它现在是世界上变化最快的冰川之一。

Not even the growing glaciers are in the clear, such as the Hubbard glacier in eastern Alaska. Towards the end of the timelapse, a large chunk of the glacier calves into the ocean.

甚至连阿拉斯加东部的哈伯德冰川(Hubbard glacier)这样不断增大的冰川也无法清晰地看到。时间快到尽头时，一大块冰川崩裂成两半，流入大海。

That calving embayment is the first sign of weakness from Hubbard Glacier in almost 50 years - it's been advancing through the historical record, Fahnestock said. "The satellite images also show that these types of calving embayments were present in the decade before Columbia retreated."

法赫内斯托克说:“这是近50年来哈伯德冰川首次出现冰川崩解的迹象，它一直在打破历史记录。”“卫星图像还显示，在哥伦比亚号撤退之前的十年间，就存在这种类型的冰解湾。”

Things weren't much better in Greenland where, according to satellite data collected between 1985 and 2018, glaciers retreated by five kilometres (three miles) on average, speeding up quite noticeably after 2000, with the ice losing more mass than it gains. And the phenomenon is not geographically constrained.

格陵兰岛的情况也好不到哪儿去。根据1985年至2018年收集的卫星数据，那里的冰川平均退缩了5公里(3英里)，2000年之后明显加速，冰的质量减少的比增加的多。而且这种现象并不受地理限制。

One thing we've noticed is that retreat has been a pattern that we've seen across the ice sheets in Greenland, said glaciologist Michalea King of The Ohio State University. "It's not just limited to one region."

俄亥俄州立大学的冰川学家Michalea King说:“我们注意到的一件事是，退缩是我们在格陵兰冰盖上看到的一种模式。”“这不仅仅局限于一个地区。”

This retreat at glacial toes - or the ends of the glaciers - was accompanied by meltwater ponds (pictured below) appearing at higher and higher altitudes.

冰川脚趾处——或冰川的末端——的退缩伴随着融水池塘(见下图)出现在越来越高的海拔。

We looked at how many lakes there are per year across the ice sheet and found an increasing trend over the last 20 years: a 27 percent increase in lakes, said glaciologist James Lea of the University of Liverpool in the UK. "We're also getting more and more lakes at higher elevations - areas that we weren't expecting to see lakes in until 2050 or 2060."

英国利物浦大学的冰川学家詹姆斯·李说:“我们研究了冰原上每年有多少个湖泊，发现在过去20年里湖泊数量呈上升趋势:增加了27%。”“我们也在越来越多的高海拔地区发现湖泊，而这些地区直到2050年或2060年才会出现湖泊。”

And, down in Antarctica, microwave radar images revealed lakes of liquid water beneath the ice and snow, which remain liquid even in the depths of winter. These lakes can destabilise ice shelves, accelerating their calving.

而且，在南极洲，微波雷达图像显示冰和雪下有液态水的湖泊，即使在隆冬也保持液态。这些湖泊会破坏冰架的稳定，加速冰架的崩解。

We've known of such lakes beneath both Antarctica and the Greenland ice sheet; but the researchers' data suggest there may be more subglacial lakes in Antarctica than we knew about, suggesting that the loss of the ice shelves may be more advanced.

我们知道在南极洲和格陵兰冰盖下都有这样的湖泊;但研究人员的数据表明，南极洲可能有比我们所知道的更多的冰下湖泊，这表明冰架的消失可能更早。

Put all together, the decades of satellite data show a trend that is not limited by region: the world's permanent ice is melting, and these videos demonstrate that stark reality more clearly than ever before.

总而言之，几十年的卫星数据显示了一种不受地域限制的趋势:世界上永久性的冰正在融化，而这些视频比以往任何时候都更清楚地展示了这一严酷的现实。

It's just one of many, many signs that Earth is undergoing rapid climate change; it's not too late to do something about it.

这只是地球正在经历快速气候变化的众多迹象之一;现在采取行动还不晚。

The researcher was presented at the 2019 Fall Meeting of the American Geophysical Union.

该研究人员出席了2019年秋季的美国地球物理联盟会议。