英国皇家科学院圣诞讲座2020行星地球（2020）

因为现在是十二月所以会很冷
So, frosty because it's December,
这很有道理 对不对
and that makes sense, doesn't it?
让我们看看我们的魔力衣橱里有什么
So, let's see what we've got in our magic wardrobe.
天啊 康斯坦西亚和阿兰娜
Oh, dear, Constancia and Alana!
我觉得这个人并没准备好
I don't think this person is ready
面对十二月寒冷的天气
for the frosty December weather.
我觉得你连今天都撑不过去
I don't think you'd make it to the end of the day.
非常感谢
Thank you so much.
所以你能明白我们英国人
So you can see why we as Brits
为什么喜欢天气预报
love weather forecasts,
因为天气总是在变
cos the weather's always changing.
气候和天气有点类似
And climate is kind of like weather,
但请把它看作是天气的平均值
but think of it as the average of weather.
它不会告诉你该从衣橱里拿什么衣服
It doesn't tell you what to take out of your wardrobe,
它实际上告诉你的是 衣橱里要放什么衣服
it actually tells you what to have IN your wardrobe.
这很重要 因为在英国气候比较温和
And that's important, cos in the UK, where it's quite mild,
我像今天这样穿也可以出门
I can get away like I'm dressing today.
穿着牛仔裤和T恤 一点没问题
You know, kind of jeans and T-shirt, nothing to worry about.
但气候会变化 慢得多 但的确会变化
But the climate does change, more slowly, but it does change.
如果你愿意思考一下这件事
And if you want to think about that, it's useful, I think,
我觉得这样想很有用 我要去海滩度假
to think, well, OK, I'm going on a holiday to a beach next...
比如说 明年
...let's say next year.
我可能会穿短裤 人字拖 戴顶太阳帽
I might want to wear shorts, flip-flops, a sun hat.
是的 为炎热的天气做好准备
Yeah, get ready for that hot day.
但如果在六千万年前去同一个海滩呢
But what about going to the same beach 60 million years ago?
那时会是什么样
You know, what would it be like then?
作为一位地理学家 这令我非常兴奋
And as a geologist, this is where I get very, very excited
因为这是一个阅读岩石记录
cos it's a chance to read the rock record
和化石记录的机会
and the fossil record.
这里是一些岩心样本
What we have here are some cores of rock
每个岩心样本大约一米长
and these are about a metre long, each core in here.
这些是通过
And these have been obtained
在苏格兰近海海床处
by drilling down a couple of kilometres
向下钻探数千米而获得的
below the seabed offshore Scotland.
这些岩石的时代跨度
These rocks span an age range of
大约有1.5至3.5亿年
about 150 to 350 million years.
我们来看看这块岩心
So let's take this core in here.
你可以看到这些颜色上不同的变化
You can see these different changes in colour.
颜色有不同的层次
There's different layers of colour.
它们是不同类型的沉积物
And they're different types of sediment,
不同的粒度 不同的成分
different grain sizes, different compositions.
这些岩石的粒度
And those changes in the grain sizes
和成分的变化
and the composition of the rock
会告诉我们诸如气候变化
tell us about things like climate changing
和构造地质学 造山运动等过程
and tectonics, mountain building,
所有这些地质过程都被记录在了这些岩石中
all of these geological processes are coded into these rocks.
但当我们思考气候时
But when we're thinking about climate,
我们真正关心的不是岩石本身
it's not the rocks themselves we're really concerned with,
而是岩石内的东西
it's what's inside the rocks.
具体说 我们是对其中的化石成分感兴趣
And specifically, we're interested in their fossil content.
如果来到这里的这个显微镜
If we come over to this microscope on here,
你会看到这些是我们偶尔在岩石中
you can see these are the sorts of fossils
发现的各种化石
we sometimes find in rocks.
这些精致的小东西
These little delicate things in here,
实在太小 我们不得不将它们放大
which are so small we're having to magnify them,
它们被称为有孔虫
are called foraminifera
可以看到 这些有孔虫
and these foraminifera, you can see in here,
不仅存在于远古海洋中
they not only existed in the ancient oceans,
也存在于现代海洋中
but they also exist in the modern oceans.
这些动物会建造外壳
And these animals, you know, they build this shell,
那种坚硬的外壳 用来保护它们自己
this hard shell, to protect themselves.
在外壳中有许多不同的元素
And in that shell are a number of different elements, you know,
它们有着不同的化学特性
they've got different chemistries,
但其中非常重要的两个元素
but two of the really important elements...
或者说在外壳中很重要的元素之一
...or one of the important elements
就是氧元素
that are in those shells is oxygen.
氧元素有不同的形式 不同的特点
And oxygen comes in different types, different flavours.
我们这里有白色的氧16
We have here a white oxygen 16,
它是一种较轻的氧同位素
which is a lighter oxygen isotope,
我们还有一个较重的蓝色氧18
and we have a heavier blue oxygen 18 here.
这些是怎么记录在我们刚从放大镜下
How is that recorded in the shells of those creatures
看到的那些生物外壳中的呢
we just looked at under the magnifying glass?
为了向你们展示个中原理 我们不惜重金
So to show you that science, we have spared no expense for you.
打造了这个美丽的远古海洋
We have created this beautiful, ancient ocean,
我会把它往前放一点
which I'm just going to slide forward here.
当然 它看起来就像一片海洋
And it looks just like an ocean, of course.
在这片海洋中
And in this ocean,
我们既有较轻的氧16 白球
we have both the lighter oxygen 16s, the whites,
也有较重的氧18 蓝球
and the heavier oxygen 18s, the blues.
我们这里将模拟热量
And we're going to simulate heat here
看看在相对寒冷的气候中 这些元素
to see how these react differently to the warming of the oceans
对海洋变暖的不同反应
in a relatively cool climate.
你可以看到 这些同位素四处跳动
And you can see those isotopes are jiggling around and...
糟糕 跑出来了个氧18 还有一个氧16
Whoops! There goes an 18. And there goes a 16.
你们看 我做得很好 我把这些淘气的同位素
You see, I'm doing quite a good job of keeping
放在一起 让它们乱蹦乱跳
these naughty isotopes together, bouncing around.
你们可以看到它们正在蒸发
And you see they're evaporating off.
我们现在可以看到 在这里
Now, what we can see is, you know, out of there,
我们发现通常蒸发出来的
what we typically find evaporating out
是那些较轻的白色氧16
are these lighter white oxygen 16s.
对它们来说至关重要的是
And the critical thing that happens to them is
它们去往更高的纬度 到了两极
they go to higher latitudes, towards the poles,
在那里 它们被困在了冰川内
where they are trapped inside ice sheets.
这些氧16被困在了冰川内
So these oxygen 16s get trapped inside the ice sheets
这意味着我们的远古海洋 如你所见
and that means our ancient ocean, as you can see here,
现在相对富含较重的氧18
is now relatively enriched in the heavier oxygen 18s.
这对我们的有孔虫意味着什么呢
Now, what does that mean for our foraminifera?
如果生长在相对寒冷的海洋中
If it's growing in that sea, when it's relatively cool,
有孔虫将会富含蓝色的 较重的
that means that foraminifera will be enriched in the blue oxygen,
氧18同位素 而含有较少的氧16同位素
heavier 18 isotopes, with less of those 16s.
如果我们让海洋变暖会发生什么呢
Now, what happens if we warm the ocean?
让我们将全球变暖 去融化那些冰 好吗
So let's warm the whole planet. We melt the ice, OK?
我们这里依然有海洋 然后我们
So we can have the ocean still here and then we have...
记住 我们这里有个巨大的冰川
Remember, we have this big ice sheet in here,
内含所有被困住的氧16
containing all of that trapped oxygen 16
所有氧16都落回到了海洋中
and it all just gets dumped back into the ocean.
你可以看到它们都在里面四处跳动
And you can see them all jiggling around in there.
通过这样做我们改变了这两种同位素的比例
So you can now see by doing that, we've changed the ratio,
也就是它们的相对丰度
the relative abundance, between those two isotopes,
也就是说
meaning that
如果生长在海洋较为温暖的时期
the foraminifera that is growing at that time in the ocean,
有孔虫就会
when it's relatively warm,
含有更多较轻的氧16
will have relatively more of those lighter oxygen 16s,
所以很有可能 你可以看到
so hopefully, you can see there
在这两种有孔虫的外壳上
those two foraminifera will have coded into those shells
记录了不同的氧同位素比例
that different ratio of those oxygen isotopes.
所以虽然这些外壳非常小
So although these shells are really tiny,
我们还需要放大它们
and we had to magnify them,
它们却是远古时代气温信息的神奇信使
they are these amazing messengers of temperature from deep time.
如果我们研究一下诸多岩层中
And if we study lots of rock layers
各式各样的化石
with lots of those different fossils
并且对这些外壳做一些化学分♥析♥
and do that chemical analysis on those shells,
我们其实能够建立一个相对清晰和准确的图像
we can actually build up a relatively clear and accurate picture
来展示气候是如何随时间变化的
of how climate has changed through time.
我们来看这个图
So I've come over to this graph here
在下面的这个轴
and what I'm showing you on this lower axis,
也就是X轴
this is the X axis here.
我把它拉到这里
Let me just pull that out for you.
这里代表大约5.5亿年
That's about 550 million years of time.
所以从5.5亿年前开始 一直到现在
So 550 million here, going through to today.