But however devastating avalanches may appear to us, |
尽管破坏性的雪崩 威胁我们的安全 |
when it comes to reshaping the Earth, they barely even scratch the surface. |
但是对于重塑世界,它 甚至不能破坏地球表面 |
It's only when snow turns into ice |
只有当雪变成冰 |
that it becomes so powerful it can change our world. |
才具有改变世界的力量 |
on this ice cliff you can actually see |
在这个冰崖,你能清晰看到 |
the transformation of snow into ice as it happens. |
雪变成冰的过程 |
Each year's snowfall creates distinct layers, many metres deep. |
每年的降雪都造成 明显的雪层,许多数米厚 |
Now, above me is the fresh snow from this winter, |
现在,在我上方是 今年新下的雪 |
and down here, this brown line, is the melt from the summer before. |
接下来,看这些褐色线, 是夏天前融化的 |
So as you go down through these layers, the snow gets older and older. |
所以你越深入观察这些 雪层,雪堆积的时间越久远 |
It's kind of like the rings of a tree |
就像树的年轮 |
with each layer being a new layer of snowfall, |
老雪层被新雪层套着 |
and it's the weight of all those snowfalls building up |
所有这些雪崩的重量 |
that starts to compress the individual snowflakes together. |
是由独立的雪花压缩而成的 |
The further down the layers you go, |
越往下接触的雪层就 |
the harder the snow becomes until you reach here. |
越硬,到了这里 |
This is a really distinctive set of snow. |
这是很特别的雪 |
and it formed several years ago. |
叫做粒雪,数年前形成 |
It's really hard, I mean, I have to dig at it with my ice axe. |
这真的很硬,我用冰镐挖它 |
It's amazing stuff. It's kind of like a bubbly fibreglass. |
这是神奇的聚集物 就像气泡玻璃纤维 |
It's beautiful. |
真漂亮 |
And what it's telling us is we're getting close to true ice. |
这告诉我们我们 离真的冰更近了 |
The more the snow is compressed, the more air is forced out of it. |
越多的雪压缩, 越多的空气被挤出 |
Removing air is what turns fluffy snow into rock hard ice. |
移除空气使蓬松的雪 变成坚硬的冰岩石 |
This is it. I've come down about 20 metres to the base of the cliff |
这里,是我降到冰崖 二十米下的地方 |
and this is pure glacial ice. |
这是纯净的冰川 |
All those snowflake crystals in there have been squeezed down |
那里的雪花结晶被填满了 |
and it gives this weird texture. |
怪异的材质 |
I mean, it's just frozen water but it's like solid rock. |
我是说,它只是冻水, 却像坚固的岩石 |
Look at that. |
看这个 |
And it's got this glassy feel to it. It's almost transparent. |
如同镜面般光滑, 甚至是透明的 |
It might take 20 years or so, but now the air has gone, |
大概经历了二十年以上, 现在里面没有空气了 |
this ice is tough enough to take on the hardest rock. |
这冰足以和最坚硬的 岩石抗衡 |
When enough ice forms, it slowly starts to slide downhill |
当足够多的冰成型,它开始 缓慢从山上滑落 |
and becomes a glacier. |
逐渐变成冰川 |
And over the last few million years, the time that humans have been around, |
不到百万年,人类遍布 世界各地的时间 |
it's ice that has been the dominant force shaping our world, |
冰是塑造我们世界的 统治力量 |
even changing the climate. |
甚至改变气候 |
Recorded from deep within the ice, |
从深入研究冰的记载中 |
these are the sounds of a glacier groaning and creaking |
冰川的声音 充满隆隆声和嘎吱声 |
as it slides down the mountain. |
因为它们从山上滑落 |
(RUMBLING) |
隆! |
(CREAKING) |
嘎吱! |
(DEEP RUMBLING) |
隆! |
They may move too slowly for the human eye to appreciate, |
它们可能速度太慢 以致人的肉眼难以分辨 |
but as a speeded-up film |
如果用加速电影,那么 阿根蒂尔冰川显示 |
ice is very much on the move. |
冰一直在频繁运动 阿根蒂尔下方的工具 |
reveal that it's travelling at half a metre a day. |
揭示了它每天移动半米 |
Here in Europe, ice is confined to high mountain ranges. |
这是欧洲,冰都 覆盖在高山上 |
But in the polar regions, |
但是在极地 |
it's cold enough for ice to cover vast areas of land. |
气候足够冷,所以冰 覆盖了大部分土地 |
In Antarctica, a single ice sheet |
南极洲,一个单独的大冰原 |
buries a continent bigger than the United States. |
覆盖了一片比美国 还大的土地 |
The ice sheet is a staggering four kilometres thick |
冰原有惊人的四千米厚 |
so only the peaks of high mountains, called nunataks, can poke through. |
所以只有被称为冰源石山的 高山的山顶,能刺穿冰层 |
This is a world where ice doesn't so much carve out a landscape, |
这是个冰没怎么雕刻的景观 |
it is the landscape. |
它自己就是景观 |
This ice world is so huge |
冰的世界相当大 |
that some of its greatest wonders can only be seen from space. |
有些伟大的景色 只有在太空中才能看到 |
These are megadunes of ice, carved by centuries of relentless winds. |
这些数百万的冰丘,被 无情的风雕刻了几个世纪 |
Each dune is six kilometres from the next. |
每个冰丘有六千米,相互连接 |
Together they cover an area twice the size of Great Britain. |
覆盖一片区域,两倍于大不列颠 |
The polar ice even creates its own climate. |
极地的冰甚至创造 自己的气候 |
The air is so cold that it holds almost no moisture |
空气太冷以至于没有湿气 |
so, in fact, Antarctica is the biggest and driest desert on Earth. |
所以,实际上,南极洲是 地球上最大和最干的荒漠 |
But beneath the ice is another even more magical world, |
但是在冰的下面是 更魔幻的世界 |
one that's been lost for more than 1 0 million years. |
一个消失了超过一千万年 的世界 |
This satellite image reveals a huge area of flat ice, |
卫星照片显示有一大块 区域是平滑的冰 |
flat because it's floating on top of an enormous lake. |
平滑是因为它浮在一个大湖上面 |
It's called Lake Vostok. |
叫做沃斯托克湖 |
It lies beneath three kilometres of ice. |
它在冰下三千米 |
The lake has been isolated from the rest of the planet |
这湖独立于星球的其他部分 |
for millions of years. |
数百万年 |
It may even be home to forms of life we've never seen. |
它甚至可能是某些我们 未曾见过的物种起源地 |
And thanks to radar, |
感谢雷达 |
for the first time we can reveal the complete landscape |
我们能第一次揭示 隐藏在南极洲冰层下的 |
that lies buried beneath Antarctica's ice. |
整个完全的风景 |
It's a strange and unfamiliar world of islands and mountains |
这是个陌生和新奇的岛屿和山脉 |
that's never been seen by humans. |
人类从未见过 |
We may take it for granted that snow and ice are very much part of our world |
我们把冰和雪视为 世界当然的一部分 |
and that glaciers and ice sheets seem to be a permanent feature of the landscape |
冰川和冰原是 永久不解冻的风景 |
but, in fact, nothing could be further from the truth. |
但是,实际上,事实并非如此 |
As far as Earth is concerned, ice is pretty unusual. |
当地球被研究以来, 冰就是非常特别的 |
For most of our planet's long history, about 90% of it, |
我们地球漫长的历史中, 有百分之九十的时间 |
there's been virtually no ice at all. |
是一点冰都没有的 |
Even the dinosaurs, that hung around for 200 million years, |
甚万至是恐龙, 两百年前满地都是 |
never saw anything like this. |
也没见过这一景象 |
We're living at an unusual time. |
我们处于一个 非常时段 |
Technically speaking, we're in the middle of an ice age right now, |
技术的说,我们处于一个 冰河世纪中期 |
but, fortunately, a relatively warm part of one. |
但幸运的是,这是个 相对暖的时代 |
Throughout Earth's four-and-a-half-billion year history, |
贯穿地球四十五亿年历史 |
ice ages have come and gone, |
冰河世纪去又来 |
sometimes reaching as far as the equator. |
有时最远到赤道 |
But they don't happen very often, |
但不经常发生 |
and when they do, they don't last that long, |
但是如果发生, 不会持续太久 |
usually no more than a few million years. |
一般不到一百万年 |
The most recent one, the one we're living in right now, |
最近这个,就是我们 正处于的 |
is believed to be the result of a rather remarkable chain of events. |
被认为是一个非凡的 连锁事件造成的 |
First, around three million years ago, |
首先,大约三百万年前 |
the continents of North and South America collided. |
南北美洲大陆冲撞 |
The result, a warm ocean current that flowed around the equator was cut off, |
结果,一个沿着赤道流动的 海洋暖流被切断 |