英国皇家科学院圣诞讲座2020行星地球（2020）

只需要少消耗化石能源
We just need to stop burning fossil fuels
让它们留在地下
and keep them in the ground,
同时减少农业排放
and we need to reduce the emissions from agriculture
和食品制♥造♥排放
and food production.
我们只需要更有行动力一点
We just need to do more of it.
但仅仅减排还不够
But reducing emissions on their own isn't going to be enough.
我要再去看一下我们的大气
I'm going to take a look again at our atmosphere.
通过减排 我们成功地
So, what we've managed to do now by reducing emissions
减少了排入大气的二氧化碳
is to slow the flow of carbon dioxide into our atmosphere.
但可以看到 总量还在增加
But as you can see, it's still building up.
问题还是在恶化
We're still making the problem worse.
所以我们还需要
So what we also need to do
将大气中的二氧化碳去除
is remove carbon dioxide from the atmosphere.
而做到这一点的最佳盟友 是大自然
And our best ally in doing that is nature.
还记得 我们从克里斯和海伦那
As you remember with Chris and Helen,
了解到海洋和陆地
we learned about the natural ability
具有天然的碳存储能力
of our oceans and the land to store carbon.
只要我们保护自然
And so, if we protect nature,
保护生态系统 恢复它们的状态
we protect ecosystems and restore them,
就可以消除大气中的二氧化碳
we can remove CO2 from the atmosphere
这就是我们要做的 能实现
and that is what we need to do to be able to achieve
将变暖控制在1.5度的方法
1.5 degrees of warming.
这个过程中大自然是我们的最佳盟友
So nature is our best ally in this process.
你们也许知道树木可以极大地存储碳
You probably know that trees have a great potential
保护我们的安全
to store carbon and keep us safe.
但是不是从没想到土壤也可以
But have you ever thought about our soil?
土壤储存了一万五千亿吨♥
So, soil holds 1,500 billion tonnes
二氧化碳
of carbon dioxide.
相当巨大 而最厉害的是泥炭地
So much. And within that, peatlands,
只覆盖地球百分之三的面♥积♥
which cover only 3% of the planet,
却储存了土壤里三分之一的碳
they hold one third of all that soil carbon.
非常了不起
They're so amazing.
但不要光听我说
But don't take my word for it.
要了解泥炭
To learn more about peat
和它难以置信的碳储存能力
and its wonderful ability to store carbon,
让我们欢迎安迪·贝尔德教授
please welcome Professor Andy Baird.
安迪 非常感谢你能出席讲座
Andy, thanks so much for joining us.
请告诉我们 是什么让泥炭如此神奇
Erm, can you tell me what makes peatlands so amazing
它们又为何是如此厉害的储碳物质呢
and why are they such amazing carbon stores?
塔拉你好 泥炭确实很神奇
Hi, Tara. Yes, they are amazing.
泥炭地的形成
I mean, peatlands have been forming
始于冰河世纪末
since the end of the last ice age
自那之后的千万年时间里
and over the thousands and thousands of years that have elapsed since then,
泥炭地一直在慢慢地存储碳
they've been slowly accumulating carbon,
于是到了今天
so that now we get to the present day
他们成为了全球最大的储碳仓
and they are huge global carbon stores.
安迪 我们可以用这块你慷慨寄来的
And, Andy, can we use this cross section of peat
泥炭横截面
that you were kind enough to send me,
来解读这个存储过程吗
to explain this storage process?
比如从样本的底部开始
Maybe starting from the bottom of the sample.
当然可以 这个样本来自于某一片泥炭沼泽
Yeah, of course. This sample was taken from a peat bog
沼泽大约有六点五米深
that is six and a half metres deep.
现场的只是很浅处的样本
Now, we've only got a shallow bit of peat here,
但即便四十厘米深处的泥炭 也依然古老
but even at a depth of 40 centimetres, this peat is old.
在在样本底部的那个深度
So, at that depth, at the bottom of the core,
形成这块泥炭的植物
the plants that form that peat,
存活于莎士比亚
they were growing at a time that Shakespeare
写出自己最后一部戏剧的年代 已经四百岁
was writing his last play, so it's 400 years old.
如果我们向上移♥动♥到剖面的中部
If we move up in the profile to about mid profile,
大约在地表以下二十厘米
so about 20 centimetres below the surface,
依然处在地下水位以下
we're still below the water table there.
在地下水位以下意味着
And being below the water table means that decay of the peat
泥煤腐烂的速度减慢
is a lot slower.
这是泥炭地
So this is part of
长♥期♥碳储存的一部分
the long-term carbon store that peatlands have.
如果我们向上移♥动♥到地表
And then if we move up to the surface,
在这里我们能看到所有转化的发生
we can see where all the dynamics happen,
我们能看到泥炭苔
we can see sphagnum mosses.
泥炭苔每年垂直生长
Now, sphagnum mosses, each year, they sort of grow up vertically
泥炭藓的底部
and the lower part of the sphagnum,
会死亡成为泥炭
it dies and it gets added to the peat,
变成泥炭地的一部分
it becomes part of the peatland.
如果成为泥炭的死亡泥炭藓的量
And if the amount of dead sphagnum moss being added to the peat
多于剖面下层腐烂的量
is more than all the decay in the profile below,
那里的泥炭就会越来越多
the peat in there will get bigger and bigger.
碳就会积累起来
It will accumulate carbon.
所以保持泥炭湿润的这整个过程
Wow. So it's this whole process of keeping the peat wet
是保证它能储存碳的关键
that is helping us to ensure that it stores carbon.
当然 没错 你需要保持泥炭地湿润
Absolutely, yes. You need to keep peatlands wet.
这让我想起两个有趣的数据
And that reminds me of two really interesting statistics.
层厚五十厘米的泥炭地
A 50 centimetre layer of peatlands,
比这个样本更深一些的地方
a little bit more than that core,
层厚五十厘米的泥炭地 每一万平方米
a 50 centimetre layer per hectare,
其碳含量比一万平方米热带雨林多
holds more carbon than a hectare of tropical rainforest.
我们想想世界上所有的森林
And if we think about all the world's forests,
它们含有大量碳
they contain a lot of carbon,
但是泥炭地含有相当于
but peatlands contain twice as much carbon
世界上所有森林加在一起碳量的两倍
as all the world's forests put together.
它们真的很神奇
They really are so amazing.
但是安迪 如果泥炭地干涸会怎样
But then, Andy, what happens if a peatland dries out?
如果你抽干泥炭地
If you drain a peatland,
你就是在降低地下水位
what you do is you lower the water table,
当地下水位下降时
and as the water table lowers,
泥炭地就会渗入空气
you allow air to get into the peat
也就是氧气 这会加快腐烂的速率
and that means oxygen, and that speeds up the rate of decay
加快十倍甚至一百多倍
perhaps by ten times, even more than 100 times.
腐烂会产生二氧化碳
And decay produces carbon dioxide
释放到大气中
and that goes into the atmosphere.
所以抽干的泥炭地
So peatlands that are drained,
可以说是二氧化碳进入大气的
they're big leakers of carbon dioxide
巨大泄露口
into the atmosphere, if you like.
安迪为什么我们在抽干泥炭地
And, Andy, why would we be draining peatlands?
我们为什么要抽干它们
Why are we drying them out?
这个问题很好
That's a good question.
抽水有很多原因
Well, drainage happens for a variety of reasons,
有时为了植树造林
sometimes to grow trees for afforestation,
也就是商品林业 有时为了农业
so commercial forestry, sometimes for agriculture,
也是为了泥炭开采更加直接 便捷
and also to make peat extraction more straightforward, easier.
人们开采泥炭也有一系列原因
And people extract peat for a range of reasons,
其中最重要的原因之一 是为你们的花♥园♥
but one of the biggest reasons is to produce compost
-生产混合肥料 -上帝啊
- for your gardens. - Oh, my goodness.
太愚蠢了 我们挖空这个神奇的储碳仓
It's so bonkers that we're digging up this amazing carbon store
竟然是为了用到我们的花♥园♥里
to use it in our gardens.
我同意 我也认为这很愚蠢
I agree. I think it's absolutely bonkers myself.
我觉得这有点像是
And I think of it as being a little bit
把大堡礁的珊瑚全都挖出来
like dredging up all the coral in the Great Barrier Reef,
压碎 然后洒在你的花♥园♥里
crushing it and then sprinkling it
好让它更漂亮一样
on your garden to make it look more pretty.
这真的很愚蠢
It's just madness,
这是在摧毁一个非常重要的生态系统
it's destroying a really important ecosystem.
我认为泥炭地和珊瑚礁一样重要
And I think peatlands are as important as our coral reefs.
所以安迪 如果它们那么重要
So if they're that important, Andy,
我们应该做什么来保护它们
what should we be doing to protect them?
我认为有两件事 泥炭地已经
I think there's two things, the peatlands that are already
在一种天然状态下 湿润状态
in a natural condition, already wet,
我们需要继续保持
we need to keep them that way.
我们坚决不能抽干它们 破坏它们
We mustn't drain them, we mustn't damage them.
然后已经抽干的
And then the peatlands that are drained
正在释放
and currently leaking loads
大量二氧化碳进入空气的泥炭地
of carbon dioxide into the atmosphere,