My subject is the future of life on Earth.
我演讲的主题是地球上生命的未来。
This is a very large and complex topic. It's the subject of futurology.
这是个非常大且复杂的话题。这是未来学的范畴。
And in fact, I am a palaeontologist, I study dinosaurs,
实际上，我是一个古生物学家，我研究的是恐龙，
and you might wonder why a palaeontologist would have something to say about the future.
你可能会想一个古生物学家对未来有什么可聊的。
However, there are some shared aspects which I will talk about, and this can provide some evidence to help us in making decisions.
我会聊一些这二者的共同点，这可以帮助我们做决定。
I'm a palaeontologist, as I say. I decided on this career when I was seven years old.
我说过我是个古生物学家。7岁时我就决定了自己的职业。
I loved dinosaurs at the age of seven, and I think these days, young people still do.
那时我就很喜欢恐龙，我觉得现在的年轻人也一样。
And I haven't changed my view since.
我从那时起就没有改变过对恐龙的喜爱。
I love the job, teaching students, going to exotic parts of the world to dig up dinosaurs, finding new facts about the history of life.
我喜欢这个工作，我教学生去世界的其他地方挖掘恐龙，找历史上存在过的生命的故事。
However, this kind of subject, studying the past, like studying the future, could be said by some not to be truly scientific.
然而，这个研究过去的学科就像研究未来一样，可以说并不是十分科学的。
And I want to explore that a little bit first, how do we do this,
我想先谈谈这一点以及我们是怎么从事这项工作的，
before we get to the point of beginning to establish some facts and figures about life and current threats.
在开始谈论一些关于生命的事实数据和现存威胁之前。
And this has been criticised by other scientists.
这一点被很多科学家批评过。
For example, 100 years ago, Sir Ernest Rutherford, a very famous physicist, Nobel Prize winner, said,
举个例子，100年前，一位著名的物理学家卢瑟福爵士，同时也是一位诺贝尔奖获得者说，
'All of science is physics, and the rest is stamp collecting.'
“所有的科学都是物理学，其他的都是集邮。”
By which he meant that if you cannot make it into mathematics or physics, it doesn't count.
他的意思是如果你不把一件事变成数学或者物理，它就不作数。
That excludes then the natural sciences, medicine and a lot of other areas.
这就把自然科学，医学和很多其他学科排除在外了。
And I think at the far end of the spectrum would be my subject, palaeontology.
那我觉得在这列表的尾端就会是我的学科古生物学。
I'd like to give you an example though,
我想举个例子，
to show you how we apply scientific methods to achieve a certain level of understanding and certainty.
告诉你我们是怎样用科学方法作出判断的。
And this is something that has been developing during my career
关于这一点，我们行业一直在发展，
so that when I started, a lot of what we did would be called a speculation or guesswork,
刚开始，我们的很多工作都被叫做是猜测或者推测，
whereas now, a lot of what we do can be tested and can be called scientific.
而现在，我们的很多工作可以被检测然后称作是科学的。
The example I'm going to take is the question I asked when I was seven, 'Could T. rex bite a car in half?'
我要举的例子是我7岁时问的那个问题：“雷克斯霸王龙可以一口把汽车咬成两半吗？”
This is a question about the most famous dinosaur, Tyrannosaurus Rex, which was huge, five tons in weight, enormous jaws and teeth.
这个问题是关于世界上最出名的恐龙，雷克斯霸王龙，它体积非常大，重5吨，有着巨大的下颌和牙齿。
Could it bite a car in half? Well, there were no cars in the Cretaceous, but let's forget that for the moment.
那么它能一口把汽车咬成两半吗？白垩纪还没有汽车，但我们先忘掉这一点。
When I started, you could only answer that question by guesswork,
一开始的时候，我们只能凭猜测来回答这个问题，
or you could make some very simple models of the skull, like levers, and try to calculate things.
或者用杠杆做一个透骨的模型试着计算。
If you were going to make a realistic model that had all the properties of the original bone and flesh of the dinosaur, you could not do it.
如果你想做一个足够逼真的模型，给它原装的骨头和恐龙的血肉，这是不可能实现的。
But now, with the power of computing, we can do this kind of thing.
但现在有了计算机，我们就可以做到。
So the way you calculate the bite force of T. rex, and the way people have done it,
人们计算雷克斯霸王龙咬合力的方法
is they scan a skull and make a three-dimensional, digital model inside the computer.
就是扫描它的头骨，再在计算机里做一个三维的数据模型。
You then divide that model into a mesh, or into a framework of elements or small components.
再把模型分成网格，或者各个部分的框架。
And each of these elements can be given physical properties so that we know the physical properties of bone of living animals.
每个部分都可以加上身体的组成部分，我们就知道它是属于活的动物。
These are material properties, like how far can you twist the bone before it breaks, how much compression can that bone take.
这些组成部分由各种材料构成，制作的时候会考虑到骨头承受多大的力会断裂，以及能被压缩到什么程度。
And so all of those properties are mapped into the skull.
然后所有的数据都会在制作头骨时用到。
And then you apply imaginary forces and increase those pressures until the thing breaks.
然后你要施加想象中的力，逐渐增加，直到它断裂。
And so the bite force of T. rex is huge. Let me lead you to the figure. Our bite force is about 800 newtons at most.
雷克斯霸王龙的咬合力是十分巨大的。我来告诉你数据。我们人类的最多咬合力大约是800牛顿。
The biggest bite force of any living animal is the great white shark, and that is about 5,000 newtons.
现存动物中咬合力最大的是白鲨，约5000牛顿。
T. rex, 50,000 newtons, ten times. And that's equivalent to five tons of weight, acting. So it could bite a car in half.
而雷克斯霸王龙的咬合力是50000牛顿，是白鲨的10倍。这跟它五吨的体重是相符的。所以它可以一口把汽车咬成两半。
Why do we believe this method? Because this method is a standard in design and architecture.
为什么我们会信任这种方法呢？因为它是设计和建筑行业的标准。
Finite element analysis is used for designing buildings like this one.
有限元素分析法同样用于建筑设计。
You don't simply build it and hope it doesn't fall down.
我们并不是把房子建起来然后希望它不要倒。
The thing is designed in a computer, it is stress-tested using this program we apply to the dinosaur.
设计是在电脑上完成的，他们测试压力的方法我们也用于恐龙。
I think we can believe it. But let's move on.
我认为这是可以相信的。我们回到正题。
That was just a brief word about how you can actually apply science,
这只是一个简单的针对你将这种方法
I would argue, to questions that are not happening at our time, in the past, or maybe in the future.
用于回应属于过去或者未来的问题的答案。
And in palaeontology, we don't just find fossils.
古生物学并不仅指寻找石油。
We also care about evolution and diversification, how groups have become diverse, how groups go extinct.
我们也关心进化和生物多样性一个群体如何变得多样化，一个群体怎样走向灭绝。
And at the moment, we are crucially concerned about extinction.
现在，我们非常关心物种灭绝。
So let's have a look at that, let's explore that. What are the current views?
所以我们来看看，我们来探讨一下。当下大家的意见是什么？
And these views are expressed not by scientists, but also by very important politicians.
这里面不光有科学家的意见，还有非常重要的政治领导人的意见。
So some of you may recall, a number of years ago, Al Gore, who was then vice president of the United States
你们可能会想起，几年前美国当时的副总统阿尔·戈尔引用了一个数字。
He quoted a figure of 100 species are going extinct every day.
他说每天都有100种生物在灭绝。
So this is a very high rate of extinction, 100 per day, which is equivalent to 40,000 per year.
这是非常高的频率，每天100种，也就是一年40000种。
At the other end, other politicians, perhaps in President Trump's camp, would say,
而在另一边，特朗普总统的阵营说，
'Don't worry about it. Extinction happens. Look at the dinosaurs. We've got nothing to do.'
“别担心。物种灭绝一直在发生。想想那些恐龙。不干我们的事。”
So how do you connect between these two positions because of course we have to think about these points.
你怎样考虑这两方的意见呢，因为我们当然有时需要思考这些问题。
The first approach that we use is to look at history. We have recent history recorded of extinction.
我们用的第一个方法就是去看历史纪录。我们的近代史有记录物种灭绝。
So many of you will be familiar with the extinct bird called the dodo.
你们中的很多人对渡渡鸟应该很熟悉。
This lived on the island of Mauritius in the Indian Ocean.
它曾生活在印度洋上的毛里求斯岛。
The dodo was a kind of fat, flightless bird related to pigeons,
渡渡鸟是一种很胖的、不会飞的鸟，它跟鸽子是亲属关系，
and a very famous image of the dodo was in the famous children's book 'Alice in Wonderland',
童话书上有一幅很出名的渡渡鸟的画，那个故事叫爱丽丝梦游仙境，
where the dodo, who is a wise, old gentleman with a walking stick organises Alice and all the animals and says to them, 'We will have a Caucus race.'
渡渡鸟在里面是一个智慧的、杵着拐杖的绅士，他负责安排爱丽丝和其他动物，跟他们说：“我们要开重要比赛啦。”
And a Caucus race is one where people start when they like and they finish when they like, and everybody gets a prize.
这场比赛随时想开始就开始，想结束就结束，谁都可以领到奖。
So that was very nice, but unfortunately the dodo in real life didn't get a prize.
这很好，不幸的是，现实中的渡渡鸟并没有奖可拿。
Because some of you may know the first records of dodos were in 1598 when seamen reported they had seen this bird.
你们可能知道最早关于渡渡鸟的记载是在1589年，一个海员报告说看见了这种鸟。
They could go on the island and catch it very easily and eat it. And within 60 years it was extinct.
他们可以去岛上很轻松的抓来这种鸟然后吃掉。不到60年他们就灭绝了。
Another example of recorded extinction is the great auk.
还有一个例子是大海雀。
This was a large bird that lived in the North Atlantic, and the great auk went extinct in 1844.
它是一种生活在北大西洋的大鸟，1844年灭绝。
How do we know that? Because collectors sent by a museum shot the last example.
我们是怎么知道的呢？因为正是博物馆的信息采集人员杀死了最后一只大海雀。
They were concerned that their museum did not have a stuffed specimen of this bird.
因为他们担心博物馆没有足够多的样本。
They heard it was going extinct, so they thought, 'We'd better get one before it dies out.'
他们听说大海雀要灭绝了，于是想：“我们最好在灭绝前抓一只。”
So these are two examples of data about extinction.
这就是两个灭绝物种的数据信息。
And indeed through the last 500 years, mankind has killed many species which are recorded like that.
在过去500年里，人类确实像记录里那样杀了很多物种。
And this is the basis of the figure that Al Gore gave. Let me explain it.
这是阿尔·戈尔给出的数据基础。我来解释一下。
He gave that figure of 100 species per day going extinct. This was based on the bird data.
他说一天有100种生物灭绝。这是基于鸟类的数据。
But we know something like 100 or two or three hundred species of birds have been killed by human activity in the last 500 years.
但我们知道在过去500年间，有大约100或200或300种鸟类死于人类活动。
And the figures are debated. It's something like from half a species to four species each year on average.
对这个数字人们争论不休。有人说平均每年只有半种到四种灭绝。
We don't know for sure because of course people didn't record everything.
因为并不是所有数据都有记录，我们并不知道确切答案。

Now, how do we scale this up to get a global figure, from birds on the one hand to all of life?
那么，我们怎样将这个数据上升到全球层面，从鸟到所有生命呢？
And the way it was done was simply to say, 'We know how many species or birds there are alive today.'
方法很简单，只要说：“我们了解目前有多少中存活的鸟类。”
There are 10,000, and the initial estimate for the diversity of all of life were 100 million.
有10000种，所有生物种类的预测最初是1亿种。
So you scale from four a day upwards, and that brings you up to this figure of 100 per day by multiplying up many times;
所以就可以从4种一天往上数，乘以几倍后你就得到了每天100种这个数字，
40,000 lost per year, 100 per day, based on that extreme high bird figure.
基于鸟类的数量，一年40000种，一天100种。
At the other end, the lowest estimate is something like one species per day.
另一方面，预估的最少的一天一种。
This is because we are not sure about that bird figure, so we could take a lower estimate,
这是因为我们不确定鸟的数量，于是就从较小的数字开始，
and also we are actually not sure about the diversity of life today either.
我们同样也不确定现在生命的种类数量。
Some of you will know that you might think we would have named every species, we would know that -- we don't.
可能你们中的一些人会想，要是我们给每一种鸟都命名了，就会知道了--我们没有这样做。
You can look at Wikipedia. There are thousands and thousands of pages describing all the living species,
看看维基百科。那里有成千上万页描述生命的文档，
but there are so many living species that we have never discovered, never described, aren't there in Wikipedia.
但也有很多我们没有发现过、描述过的、不在维基百科里的。
So there is that uncertainty. One hundred million? Ten million? We don't know.
所以就存在不确定性。一亿种？一千万种？我们不知道。
Those are the estimates of numbers of species going extinct each day.
这只是猜测的每天灭亡的种类数量。
One per day, one hundred per day. Do we worry about that?
一天一种，或是一天一百种。我们需要担心吗？
This is where palaeontology comes in first, because fossil data allows us to calculate what would be the normal rate of extinction.
在这一点古生物学就了解的比较多，因为古生物的化石可以让我们了解到生物正常的灭亡速度。
Species do go extinct, so this politician over here was quite right. But was Al Gore right? We don't know.
物种确实会灭亡，所以这位政治家是对的。但阿尔·戈尔说的对吗？我们不知道。
You know, he was giving that high figure -- maybe somewhere in between.
他给出了这样高的一个数字--也许实际上是一个居中的数字。
But what is the norm? Is one a day okay? It doesn't sound too many.
那正常情况下是多少呢？一天一种可以吗？听起来并不多。
If there are millions and millions of species, it is far too high.
但如果有成百上千万种，那就太多了。
We know that the average duration of a species is two million years.
我们知道平均一个物种的存货期是大约两百万年。
They originate, they go extinct. Two million years.
两百万年内他们出现再消亡。
And that means, as they come and go, on average,
这就意味着，随着它们的出现和消失，
we would expect the extinction of five million species every million years, which is five species per year.
我们可以猜测每一百万年有五百万种生物消失，也就是一年五种。
So that does contrast remarkably even at the lowest estimate of human impact
所以这就跟预估的人类影响造成的灭绝数量不一致了，
500 species per year is 100 times the normal rate of 5 per year.
每年500种是正常数据，也就是每年5种的100倍。
And at the bottom there is the dodo, just in case you weren't sure what it looked like.
最下面是渡渡鸟，以防有人不知道它长什么样子。
So I want to look at two other topics briefly. One is risk.
我想聊聊另外两个话题。一是风险。
And so, one of the questions we would have estimating the total numbers is one thing.
这是我们预测灭亡数量需要考虑的问题之一。
We have learned that we are impacting life harder than we should be. Human activity is causing extinction.
我们知道我们对物种造成的影响比想象中要大。人类活动会造成物种灭绝。
What about risk? It's easy to say of course, the dodo was stupid, it lived on one island,
那么风险呢？当然很容易说渡渡鸟很笨，它们只生活在一个岛上，
it just stood around and allowed itself to be hit on the head.
随便站着所以人类很容易打到它的头。
To an extent. We worry about elephants, we worry about pandas, we worry about many individual species.
扩展一下来说。我们担心大象，担心熊猫，担心很多种生物。
Many of those have high-risk factors. So for example, an elephant is very large.
很多其实都处在高风险之中。比如，大象体积很大。
This means they need a lot of food, they need a lot of territory to walk around.
这意味着他们需要很多食物，需要很大的空间走动。
And so it's much harder to keep a sufficiently large population of elephants breeding and successfully in the wild.
在野外找一块地方供足够多的大象生活是很难的。
We don't need to worry about rats, for example. They're small and there's lots of them.
比如，我们就不需要担心老鼠。他们很小数量又多。
So body size is one risk factor. Being big is not a good thing if you want to survive as a species.
所以体积是风险之一。太大的体积不利于生存。
What about the panda? They're not so huge. They're about human size.
那熊猫呢？他们不大。体型跟人类差不多。
They have a specialised diet. They have evolved into a crazy position.
还有特别的饮食习惯。他们已经进化到一个疯狂的地步了。
As you know, they are eating bamboo without the real ability to consume it properly.
大家知道他们吃竹子，但又不能很好的做进食规划。
If that food supply disappears, they're stuck. So, secondly, restricted diet is a problem.
如果食物来源断了，他们就完了。所以第二，有限的食物种类也是问题。
The third one is shown by the dodo. If you live in only a very small geographic area rather than over the whole world, you are at risk.
第三是渡渡鸟表现出来的问题。如果你只生活在很小的一块地方，而不是全世界都有你的族群，你就面临着很大的风险。
So there are three things to be:
所以这三点很重要：
medium-sized or small, if you want to survive; broad diet, willing to eat everything; and living over the whole world.
中等体型或者很小，如果你想生存下去；爱好广泛，什么都吃；全世界都有你的族。
So that includes human beings and rats and cockroaches.
这就包括了人类、老鼠和蟑螂。
They will survive and many other species will not survive whatever we do.
他们会生存下来，而很多其他的物种不论怎样都生存不下来。
So risk is something we can determine from the present day, but also we can test when we look at mass extinctions in the past.
所以风险是我们从现在开始就可以控制的，但我们同样可以用过去大规模的种族灭绝现象来做测试。
So this is where we come back to palaeontology,
这里我们说回古生物学，
because I think most people here know that the end of the dinosaurs was marked by a mass extinction.
大部分人都知道恐龙是在一场大规模的生物灭绝发生时死亡的。
Many millions or thousands of species died out rather rapidly.
成百上千万种物种突然死亡。
The cause of that extinction definitely was largely the impact of a meteorite, a huge asteroid, maybe ten kilometres across,
这场灭绝的原因是受陨石的影响，一颗巨大的小行星，直径大概有10千米，
and the model for extinction of the dinosaurs 66 million years ago was the asteroid hit the Earth
大概在6600万年前撞击了地球，恐龙就是在那时候灭绝的，
this is unpredictable, when this may happen or not -- it penetrated into the crust, it vaporised,
无法预测这种事是否会发生--这颗小行星砸穿了陆地，开始蒸发，
and all that rock of the asteroid plus the crust that it had penetrated turned into rocks and dust, mainly dust.
小行星携带的岩石和被砸穿的地面的岩石变成了碎石和灰尘，主要是灰尘。
This was thrown up high into the atmosphere and went all round the Earth, blacking out the sun,
灰尘高高的扬起进入大气层包裹了地球，挡住了太阳，
and so that you get two effects there, no light, no heat.
于是就产生了两种影响，没有光，没有热。
So there was a cessation of photosynthesis. The plants died. There was darkness and cold.
光合作用停止。植物死亡。到处都是黑暗和寒冷。
So this was not good for dinosaurs and other groups that enjoyed the warm climates, and so you get extinction.
这些对恐龙和其他喜欢温暖气候的生物都是不利的，于是物种就这样灭绝了。
And you might think, of course, 'What do we learn from this?'
当然你可能会想：“我们从中学到了什么呢？”
Yes, that's all very well, but that's not something we can do anything about really.
这个问题很好，但我们的确做不了什么。
And indeed, asteroids do come close to the Earth from time to time.
而且小行星确实时不时会靠近地球。
Earlier this week, one did. Luckily it didn't hit the Earth. We can't really prepare.
这周前几天就有一个，幸运的是它没有撞到地球。我们其实没办法做准备。
But the key point is that the other mass extinctions in the history of life were not caused by impact.
但重点是另一次大规模的物种灭绝不是被这影响到的。
They were caused by climate change. Immediately, you can see now how that matters.
他们是受气候变化的影响。你们很快会看到影响有多大。
I will briefly characterise one of them that I have worked upon.
我会简单概括一下我在研究的这一案例。
At the end of the Permian Period, 250 million years ago, there was another major extinction.
二叠纪尾期，2亿5千年前，有一次大规模的物种灭绝。
This was before the dinosaurs. And the sequence of events was that massive volcanoes errupted in Russia.
还在恐龙灭绝之前。气候变化的后果是俄罗斯的火山大量喷发。
They were so huge that they poured out enormous amounts of lava, of course,
势头很猛，当然有大量的岩浆被喷发出来，
but more importantly, they poured out gases into the atmosphere, including carbon dioxide.
但更重要的是，大量气体被输送到大气层，其中就包括二氧化碳。
And carbon dioxide is famous as a greenhouse gas, meaning it heats the atmosphere.
二氧化碳是一种非常出名的温室气体，这就意味着它会加热大气层。
We have primary evidence that around the equator, ocean temperatures warmed up to 40 degrees plus.
我们有证据表明赤道周围海平面温度达到了40多度。
So this is like a very warm shower. You might think that's OK.
简直像喜热水澡一样。你可能觉得没关系。
Maybe for 10 minutes but not for day after day after day.
10分钟可能还好，但是一天接着一天可就不好了。
And so life had to progressively flee out of the equatorial zones.
所以很多生物逃离了赤道，逃到两级地区。
It became crowded at the poles and there was great extinction.
当时也有很大规模的生物灭绝的现象。
So we learnt from that that carbon dioxide and global warming can cause extinction
于是我们就知道了二氧化碳和全球变暖都会导致生物灭绝，
whatever the cause of that carbon dioxide, whether it comes from volcanoes or human activity.
无论二氧化碳的源头是什么，无论是火山喷发还是人类活动。
So we've learnt three things that we can illustrate and use for predicting into the future, what may happen to life.
我们学到了三件事，可以用来预测未来会发生什么。
We've learnt that we can calculate the rate of extinction by looking at historical extinctions
我们学会了通过看历史物种灭亡数据计算正常的物种灭亡速率，
and at that rate of extinction, even at the minimal figures, it's at least one hundred times what it ought to be.
根据这个数字，可以判断即使是人类猜测的数据的最小值，也是正常数据的一百倍。
Secondly, we've learnt something about risk, which species are most at risk of extinction, and I think that's fairly straightforward.
其次我们学习了风险，哪种生物面临的灭绝风险最大，我觉得这个答案很明显。
But we need the evidence to be able to argue the case.
但是还需要证据来证明。
And thirdly, we've learnt that the whole history of the Earth records a rich record of climate change.
第三，我们知道了地球的历史完整的记录了气候变化史。
We don't need to do experiments, we don't need to imagine what a world would be like without the polar ice caps.
我们不需要做实验，不需要想象没有了两极冰川世界会是什么样子。
It has existed and we can study it. So to conclude, my aim has not been simply to spread doom and gloom,
这样的时期曾存在过，我们可以进行研究。所以我的结论是，我的目的并不是简单的散播恐慌，
but to indicate that we have the power to change.
而是告诉大家我们有能力做出改变。
And in order to change, we have to accept reality along the lines that we're mentioning.
为了做出改变，我们必须接受历史和现实。
And we have to ask the right questions about what we should do.
我们应该对要做的事问正确的问题。
And in order to decide what we should do, we need to use evidence.
而为了判断要做的是什么，我们就需要证据。
And some great evidence comes from the history of the Earth and the history of life. Thank you very much.
好的证据就来自于地球和生命的历史。谢谢大家。