Should we create a solar shade to cool the earth? | Danny Hillis

翻译人员: Zihao Wang 校对人员: Yolanda Zhang

[A provocation from Danny Hillis:]

【来自丹尼希利斯的挑衅：

[It's time to start talking about engineering our climate]

是时候谈谈如何治理气候问题了】

What if there was a way to build a thermostat

是否可以创造一个恒温器，

that allowed you to turn down the temperature of the earth

能在任何时候

anytime you wanted?

给地球降温？

Now, you would think if somebody had a plausible idea about how to do that,

你也许会认为，如果有人已经 找到了可行的方法，

everybody would be very excited about it,

每个人都会非常激动，

and there would be lots of research on how to do it.

而且关于这方面的研究也会有很多。

But in fact, a lot of people do understand how to do that.

事实是，许多人明白如何做，

But there's not much support for research in this area.

但是，这些方法并没有 得到相关研究的支持。

And I think part of it

我认为，其中部分原因是

is because there are some real misunderstandings about it.

人们对这项研究存在着误解。

So I'm not going to try to convince you today that this is a good idea.

今天，我不会说服大家承认 我要说的是一个好办法，

But I am going to try to get your curiosity going about it

但我会尝试让你们 对治理气候变化感兴趣，

and clear up some of the misunderstandings.

并消除其中一些误解。

So, the basic idea of solar geoengineering

太阳能地球工程的基本思想就是

is that we can cool things down

我们通过把一部分阳光

just by reflecting a little bit more sunlight

反射回太空的方式，

back into space.

给地表的物体降温。

And ideas about how to do this have been around literally for decades.

数十年来人们都在讨论 如何实现这种想法，

Clouds are a great way to do that, these low-lying clouds.

低空的云，就是一种很棒的方式，

Everybody knows it's cooler under a cloud.

人们都知道，云底下凉快。

I like this cloud because it has exactly the same water content

我喜欢这种云是因为，它的含水量

as the transparent air around it.

和周围的空气一致。

And it just shows that even a little bit of a change in the flow of the air

这就意味着，只要空气的 流动发生一点改变，

can cause a cloud to form.

就能形成云。

We make artificial clouds all the time.

我们经常在空中制造人造云，

These are contrails, which are artificial water clouds

这些云是飞机飞行痕迹， 是人造水云，

that are made by the passing of a jet engine.

是由喷气式发动机产生的。

And so, we're already changing the clouds on earth.

我们已经在不经意间改变

By accident.

地球上的云了。

Or, if you like to believe it, by supersecret government conspiracy.

或者，你可能更愿意认为 这是政府的绝密阴谋。

(Laughter)

（笑声）

But we are already doing this quite a lot.

我们在这方面已经做了很多工作。

This is a NASA picture of shipping lanes.

这是一张由NASA 拍摄的船舶航线图。

Passing ships actually cause clouds to form,

船舶的航行会导致云的形成，

and this is a big enough effect

而且这种影响效应非常大，

that it actually helps reduce global warming already by about a degree.

大到能让大气温度降低一度， 从而减缓了全球变暖效应。

So we already are doing solar engineering.

也就是说，我们已经 开始研究太阳能工程了。

There's lots of ideas about how to do this.

有很多关于实现这一工程的想法，

People have looked at everything,

人们着眼于方方面面，

from building giant parasols out into space

从在太空建造巨大的遮阳伞，

to fizzing bubble waters in the ocean.

到在海洋里产生气泡。

And some of these are actually very plausible ideas.

其中有一部分想法是十分可行的。

One that was published recently by David Keith at Harvard

最近，哈佛的大卫 · 凯斯 提出了一个想法，

is to take chalk and put dust up into the stratosphere,

将白垩粉（如粉笔灰）洒到平流层中，

where it reflects off sunlight.

用来反射太阳光。

And that's a really neat idea,

这确实是一个不错的注意，

because chalk is one of the most common minerals on earth,

因为白垩是地球上 最常见的矿物之一，

and it's very safe -- it's so safe, we put it into baby food.

而且非常安全—— 安全到可以添加到婴儿的食物中。

And basically, if you throw chalk up into the stratosphere,

如果你把白垩投入到平流层中，

it comes down in a couple of years all by itself, dissolved in rainwater.

它会花几年的时间才落到地面， 并溶解在雨水中。

Now, before you start worrying about all this chalk in your rainwater,

在你担心雨水中的白垩之前，

let me explain to you how little of it it actually takes.

我先向你们解释一下， 我们使用的白垩是有多么的少。

And that turns out to be very easy to calculate.

可以证明它的用量非常容易计算。

This is a back-of-the-envelope calculation I made.

这是我粗略的计算。

(Laughter)

（笑声）

(Applause)

（掌声）

I assure you, people have done much more careful calculations,

我可以向各位保证， 已经有人进行过更详细的计算，

and it comes out with the same answer,

得出的结果是一致的——

which is that you have to put chalk up at the rate of about 10 teragrams a year

你需要每年以10太克（1Tg=10^9公斤）的 速率向平流层投放白垩，

to undo the effects of the CO2 that we've already done --

来消除二氧化碳的影响， 这是我们已经在做的——

just in terms of temperature, not all the effects, but the temperature.

仅仅是温度方面的影响， 不包含其他的影响。

So what does that look like?

那么这个数字是什么概念？

I can't visualize 10 teragrams per year.

我想象不出每年 10太克是什么样子的。

So I asked the Cambridge Fire Department and Taylor Milsal

所以，我请了剑桥消防部门， 以及泰勒 · 米尔索

to lend me a hand.

帮我一个忙。

This is a hose pumping water at 10 teragrams a year.

这根水管的出水量 就是一年10太克。

And that is how much

这个规模

you would have to pump into the stratosphere

就是让地球降温到 工业时代前的水平，

to cool the earth back down to pre-industrial levels.

需要将白垩注入到平流层的量。

And it's amazingly little; it's like one hose for the entire earth.

这个量小得惊人，整个地球 只需要这一根水管就够了。

Now of course, you wouldn't really use a hose,

当然，你不必使用一根水管，

you'd fly it up in airplanes or something like that.

可以通过飞机，或其他 类似的方法将白垩带上去。

But it's so little, it would be like putting a handful of chalk

这个量非常的小， 就好像用手抓一把白垩

into every Olympic swimming pool full of rain.

放入与奥运会标准泳池 等量的雨水中。

It's almost nothing.

很难察觉出变化。

So why don't people like this idea?

那么为什么 人们不喜欢这种方法？

Why isn't it taken more seriously?

为什么不重视这种方法？

And there are some very good reasons for that.

有一些很好的理由。

A lot of people really don't think we should be talking about this at all.

有很多人不认为 我们应当去研究这种方法。

And, in fact, I have some very good friends in the audience

事实上，在座的观众中 有一些是我非常要好的朋友，

who I respect a lot,

我非常尊敬他们，

who really don't think I should be talking about this.

他们认为我不应该研究这个。

And the reason is that they're concerned

因为他们关心的是，

that if people imagine there's some easy way out,

人们是否还能想出更简单的办法，

that we won't give up our addiction to fossil fuels.

来摆脱对化石燃料的依赖。

And I do worry about that.

我也关心这一点，

I think it's actually a serious problem.

因为我认为这是 一个很严重的问题，

But there's also, I think, a deeper problem,

也是一个很深奥的问题。

which is: nobody likes the idea of messing with the entire earth --

没有人喜欢让整个地球 陷入混乱的想法，

I certainly don't.

我当然也不喜欢。

I love this planet, I really do.

我喜欢这个星球，说真的，

And I don't want to mess with it.

我不想给地球制造任何麻烦。

But we're already changing our atmosphere,

但是我们已经在改变 我们的大气层了，

we're already messing with it.

我们已经把它搞得乌烟瘴气了。

And so I think it makes sense for us to look for ways

所以我们应该寻找一些方法，

to mitigate that impact.

减缓大气变化造成的影响。

And we need to do research to do that.

这就意味着我们需要去研究它，

We need to understand the science behind that.

我们需要弄清楚 这背后的科学道理。

I've noticed that there's a theme that's kind of developed at TED,

我注意到，在TED中 有关于发展的主题，

which is kind of, "fear versus hope,"

类似于“恐惧与希望”，

or "creativity versus caution."

或者是“创造与谨慎”。

And of course, we need both of those.

当然，我们也需要这些思想。

So there aren't any silver bullets.

但这不是完美的解决办法，

This is certainly not a silver bullet.

这确实不是完美的解决办法。

But we need science to tell us what our options are;

但我们需要通过科学知道， 我们有哪些选择；

that informs both our creativity and our caution.

这会为我们的创造力和 谨慎态度带来指导。

So I am an optimist about our future selves,

对人类的未来， 我是一个乐观主义者，

but I'm not an optimist because I think our problems are small.

我乐观的原因 并不是因为这些问题很小，

I'm an optimist because I think our capacity to deal with our problems

而是因为我认为 我们有能力解决这些问题，

is much greater than we imagine.

而且方法比我们想象的要好。

Thank you very much.

非常感谢。

(Applause)

（掌声）

This talk sparked a lot of controversy at TED2017,

这场演讲在 TED2017 引起了许多议论，

我们鼓励观众们 上网了解这些讨论，

and we encourage you to look at discussions online

了解其他的观点。

to see other points of view.