James Hansen: Why I must speak out about climate change

翻译人员: Jing Gao 校对人员: Ting Huang

What do I know

我知道了些什么，

that would cause me,

会驱使我这样一个

a reticent, Midwestern scientist,

沉默寡言、来自中西部的科学家

to get myself arrested

到白宫门前去抗议

in front of the White House protesting?

而被捕？

And what would you do

而你又会怎样做

if you knew what I know?

如果你知道我所知道的？

Let's start with how I got to this point.

我们从我的成长历程讲起。

I was lucky to grow up

我很幸运。

at a time when it was not difficult

在我成长的那个年代，

for the child of a tenant farmer

一个佃农的孩子

to make his way to the state university.

想上州立大学还不那么难。

And I was really lucky

我还不是一般得幸运。

to go to the University of Iowa

我大学去了爱荷华州立大学。

where I could study under Professor James Van Allen

在那里，我得到了James Van Allen教授的悉心指教。

who built instruments

Van Allen教授为美国最早的卫星

for the first U.S. satellites.

制造仪器。

Professor Van Allen told me

教授告诉我，

about observations of Venus,

对金星的观察显示，

that there was intense microwave radiation.

金星上有强烈的微波辐射。

Did it mean that Venus had an ionosphere?

这是表明金星上有电离层，

Or was Venus extremely hot?

还是说金星上非常热？

The right answer,

经苏联的金星航天器肯定，

confirmed by the Soviet Venera spacecraft,

正确的答案是，

was that Venus was very hot --

金星上非常热——

900 degrees Fahrenheit.

温度高达900华氏度。

And it was kept hot

因为金星上空有一层厚厚的二氧化碳气层，

by a thick carbon dioxide atmosphere.

这个高温得以一直保持。

I was fortunate to join NASA

我非常幸运地加入了国家航空航天局，

and successfully propose

并成功地提出了一项

an experiment to fly to Venus.

飞往金星的实验。

Our instrument took this image

我们的仪器拍摄到这张照片。

of the veil of Venus,

照片上正是金星的面纱。

which turned out to be

这层面纱实际上是

a smog of sulfuric acid.

一层含硫酸的雾。

But while our instrument was being built,

但就在我们制造仪器期间，

I became involved in calculations

我参与

of the greenhouse effect

计算地球上的

here on Earth,

温室效应，

because we realized

因为我们意识到

that our atmospheric composition was changing.

我们的大气层成分正在发生变化。

Eventually, I resigned

最终，我辞去了

as principal investigator

我们金星实验组

on our Venus experiment

首席调查员的职务，

because a planet changing before our eyes

因为一颗就在我们眼前变化的行星

is more interesting and important.

要更有趣，也更重要。

Its changes will affect all of humanity.

它的变化会影响到全人类。

The greenhouse effect had been well understood

一个世纪来，

for more than a century.

人类已充分地了解了温室效应。

British physicist John Tyndall,

英国物理学家John Tyndall

in the 1850's,

在19世纪50年代时

made laboratory measurements

对红外辐射

of the infrared radiation,

也就是热辐射

which is heat.

进行了实验测量。

And he showed that gasses such as CO2 absorb heat,

他向我们展示，二氧化碳等气体吸收热，

thus acting like a blanket

就像是一层毯子，

warming Earth's surface.

给地球的表面加温。

I worked with other scientists

我和其他科学家

to analyze Earth climate observations.

一起分析地球的气候变化。

In 1981,

在1981年，

we published an article in Science magazine

我们在《科学》杂志上发表了一篇论文，

concluding that observed warming

我们的结论是，

of 0.4 degrees Celsius

在上个世纪，

in the prior century

地球的温度提升了0.4摄氏度，

was consistent with the greenhouse effect

这和更多的二氧化碳

of increasing CO2.

带来温室效应是相符的。

That Earth would likely warm in the 1980's,

地球很有可能会在20世纪80年代变暖，

and warming would exceed

到20世纪末，

the noise level of random weather

地球变暖的严重程度将超过

by the end of the century.

随机天气带来的噪音干扰。

We also said that the 21st century

我们还提出到21世纪

would see shifting climate zones,

地球的气候区将发生变化，

creation of drought-prone regions

北美和亚洲会

in North America and Asia,

出现易旱区；

erosion of ice sheets, rising sea levels

冰盖将融化，海平面将上升，

and opening of the fabled Northwest Passage.

传说中的西北通道将打开。

All of these impacts

从我们发表论文起，

have since either happened

所有的这些影响都已经发生了，

or are now well under way.

或正在发生。

That paper was reported on the front page of the New York Times

我们那篇论文上了《纽约时报》的头版，

and led to me testifying to Congress

在20世纪80年代，

in the 1980's,

我得以向国会证明我的发现。

testimony in which I emphasized

在陈述中，我强调

that global warming increases both extremes

全球变暖会加剧地球水循环的

of the Earth's water cycle.

两个极端。

Heatwaves and droughts on one hand,

一方面，变暖会直接

directly from the warming,

加剧热浪和干旱，

but also, because a warmer atmosphere

但同时，因为一个更暖的大气层

holds more water vapor

会保存更多的水汽

with its latent energy,

和其潜在能量，

rainfall will become

降雨活动也将变得

in more extreme events.

更为极端。

There will be stronger storms and greater flooding.

风暴会变得更强，洪水会变得更猛烈。

Global warming hoopla

全球变暖像是个套圈游戏，

became time-consuming

我在上面花的时间越来越多，

and distracted me from doing science --

都没心思做科研了——

partly because I had complained

其中一个原因是我之前抱怨说

that the White House altered my testimony.

白宫修改了我的证词。

So I decided to go back

于是我决定回归到

to strictly doing science

只做科研，

and leave the communication to others.

把这些跟人沟通的活儿都留给别人。

By 15 years later,

15年后，

evidence of global warming was much stronger.

全球变暖的证据越来越明显。

Most of the things mentioned in our 1981 paper

我们在1981的那篇论文里提到的大多数东西

were facts.

都变成了事实。

I had the privilege to speak twice

我很荣幸地两次

to the president's climate task force.

在总统的气候专案组前演讲。

But energy policies continued to focus

但是能源政策的重点依旧是

on finding more fossil fuels.

找到更多的化石燃料。

By then we had two grandchildren,

那时我已经有一个孙子和一个孙女，

Sophie and Connor.

Sophie和Connor。

I decided

我决定

that I did not want them in the future

我不希望他们在将来说，

to say, "Opa understood what was happening,

“爷爷知道发生了些什么，

but he didn't make it clear."

但他没有告诉大家。“

So I decided to give a public talk

于是我决定做场公众演讲，

criticizing the lack of an appropriate energy policy.

批评政府没有一项合适的能源政策。

I gave the talk at the University of Iowa in 2004

2004年我在爱荷华大学做了演讲，

and at the 2005 meeting

2005年我在

of the American Geophysical Union.

美国地球物理联盟的会议演讲。

This led to calls

因为这些演讲，

from the White House to NASA headquarters

从白宫到国家航空航天局总局都纷纷给我打电话，

and I was told that I could not give any talks or speak with the media

告诉我如果我没有得到

without prior explicit approval

航空航天局总局的明确批准，

by NASA headquarters.

我就不能做演讲或者联系媒体。

After I informed the New York Times

在我告诉《纽约时报》

about these restrictions,

我言论受到限制后，

NASA was forced to end the censorship.

国家航空航天局取消了对我的审查。

But there were consequences.

但这是造成了其他后果。

I had been using the first line

之后我一直在用

of the NASA mission statement,

国家航空航天局的任务声明的第一句话，

"To understand and protect the home planet,"

“为了了解和保护我们的地球家园”，

to justify my talks.

来给我的演讲作个幌子。

Soon the first line of the mission statement

很快航空航天局的任务声明的第一句话

was deleted, never to appear again.

就被删除了，以后也不会再出现了。

Over the next few years

在之后的几年里，

I was drawn more and more

我对宣传

into trying to communicate the urgency

改变能源政策的紧急性

of a change in energy policies,

越来越认真，

while still researching the physics of climate change.

同时我还在研究气候变化物理。

Let me describe the most important conclusion from the physics --

我来讲一下物理研究得出的最重要的结论。

first, from Earth's energy balance

首先，从地球能量平衡角度；

and, second, from Earth's climate history.

其次，从地球气候历史角度。

Adding CO2 to the air

向空气中排入二氧化碳

is like throwing another blanket on the bed.

就像是在床上又加了床毯子。

It reduces Earth's heat radiation to space,

它减少从地球散向宇宙的热辐射，

so there's a temporary energy imbalance.

造成暂时性的能量不平衡。

More energy is coming in

进入地球的能量

than going out,

比离开地球的能量多，

until Earth warms up enough

直到地球继续升温

to again radiate to space

再次向太空辐射出

as much energy as it absorbs from the Sun.

它从太阳吸收到的同样多的能量。

So the key quantity

这其中的关键量

is Earth's energy imbalance.

是地球的能量不平衡。

Is there more energy coming in

进入地球的能量

than going out?

是否比离开地球的多？

If so, more warming is in the pipeline.

如果是的，更严重的变暖正在萌生。

It will occur without adding any more greenhouse gasses.

地球会继续升温，虽然温室气体没有增多。

Now finally,

现在，

we can measure Earth's energy imbalance precisely

通过测量地球热储层中的热量，

by measuring the heat content

我们能精确地

in Earth's heat reservoirs.

测量出地球的能源不平衡。

The biggest reservoir, the ocean, was the least well measured,

最大的热储层，海洋，也曾是被测量得最不精确的，

until more than 3,000 Argo floats

直到3000多个Argo浮标

were distributed around the world's ocean.

被分散到海洋各地。

These floats reveal

这些浮标显示

that the upper half of the ocean

海洋的上半层

is gaining heat at a substantial rate.

正在飞快地吸收热量。

The deep ocean is also gaining heat at a smaller rate,

深洋也在吸收热量，虽然速度要慢一些，

and energy is going

吸收的热量不断进到

into the net melting of ice all around the planet.

地球上的融冰中。

And the land, to depths of tens of meters,

陆地到十米深的地方，

is also warming.

也在升温。

The total energy imbalance now

现在的总能量不平衡

is about six-tenths of a watt per square meter.

大概有每平方米0.6瓦。

That may not sound like much,

这听起来好像不是很多，

but when added up over the whole world, it's enormous.

但把全世界的都加起来，这个数字就大得惊人。

It's about 20 times greater

它大概比所有人类用能量的

than the rate of energy use by all of humanity.

多出20倍。

It's equivalent to exploding

它等同于一年365天

400,000 Hiroshima atomic bombs per day

每天炸掉40万个

365 days per year.

广岛原子弹。

That's how much extra energy

地球每天都在吸收

Earth is gaining each day.

这样多的额外能量。

This imbalance,

这个不平衡意味着

if we want to stabilize climate,

如果我们想要稳定气候的话，

means that we must reduce CO2

我们就必须降低二氧化碳浓度，

from 391 ppm, parts per million,

从391ppm，即百万分之三百九十一，

back to 350 ppm.

降回到350ppm。

That is the change needed to restore energy balance

如果我们想重建能量平衡，阻止地球变得更暖，

and prevent further warming.

我们就必须做这样的改变。

Climate change deniers argue

否认气候变化的人说，

that the Sun is the main cause of climate change.

太阳是地球气候变化的主要原因。

But the measured energy imbalance occurred

但是我们测量到的能量不平衡发生在

during the deepest solar minimum in the record,

自人类记录以来太阳活动最弱时期，

when the Sun's energy reaching Earth was least.

这期间太阳到达地球的能量是最少的。

Yet, there was more energy coming in than going out.

然而，地球收到的能量还是比散发的多。

This shows that the effect of the Sun's variations on climate

这表明太阳辐射对气候的影响

is overwhelmed by the increasing greenhouse gasses,

已经被增加的温室气体减弱，

mainly from burning fossil fuels.

这些气体主要来自化石燃料的燃烧。

Now consider Earth's climate history.

现在想想地球的气候史。

These curves for global temperature,

这些全球温度的曲线，

atmospheric CO2 and sea level

大气层二氧化碳和海平面的曲线，

were derived from ocean cores and Antarctic ice cores,

是通过测量海洋芯、南极冰芯、

from ocean sediments and snowflakes

和海洋沉淀物和雪花得到的。

that piled up year after year

80多万年来，

over 800,000 years

这些沉淀物和雪花不断积累，

forming a two-mile thick ice sheet.

最后形成了一个2英里厚的冰盖。

As you see, there's a high correlation

大家都可以看到，温度、二氧化碳和海平面之间

between temperature, CO2 and sea level.

有着极大的关联。

Careful examination shows

仔细的研究显示

that the temperature changes

气温变化

slightly lead the CO2 changes

会引发几世纪后的

by a few centuries.

二氧化碳变化。

Climate change deniers like to use this fact

否定气候变化的人喜欢用这个事实

to confuse and trick the public

来迷惑和愚弄大众。

by saying, "Look, the temperature causes CO2 to change,

他们会说：“看，是温度引起了二氧化碳变化，

not vice versa."

而不是二氧化碳引起温度变化。”

But that lag

但是这正是

is exactly what is expected.

我们所预期的。

Small changes in Earth's orbit

经过数十万年，地球的轨道

that occur over tens to hundreds of thousands of years

会产生小小的变化，

alter the distribution

这些变化会改变

of sunlight on Earth.

地球各部分得到的阳光。

When there is more sunlight

如果高纬度地区

at high latitudes in summer, ice sheets melt.

在夏天得到更多的日照，冰盖就会融化。

Shrinking ice sheets

减少后的冰盖会

make the planet darker,

让地球变得更暗，

so it absorbs more sunlight

地球因此会吸收更多的阳光，

and becomes warmer.

变得更加温暖。

A warmer ocean releases CO2,

升温的海洋会释放二氧化碳，

just as a warm Coca-Cola does.

就像升温的可口可乐一样。

And more CO2 causes more warming.

更多的二氧化碳会引发更严重的变暖。

So CO2, methane, and ice sheets

因此，二氧化碳、甲烷和冰盖

were feedbacks

都是放大了

that amplified global temperature change

全球温度变化的反馈，

causing these ancient climate oscillations to be huge,

尽管气候变化最初是因小小的变化而起，

even though the climate change was initiated

这些古老的气候变化指数

by a very weak forcing.

也会变得非常大。

The important point

重要的问题是

is that these same amplifying feedbacks

这些同样的放大的反馈

will occur today.

会出现在现在。

The physics does not change.

物理原理是不会变的。

As Earth warms,

随着地球变暖，

now because of extra CO2 we put in the atmosphere,

现在是因为我们排入大气层的多余的二氧化碳，

ice will melt,

冰层将会融化，

and CO2 and methane will be released

升温的海洋和融化的冻土

by warming ocean and melting permafrost.

会释放出二氧化碳和甲烷。

While we can't say exactly how fast

虽然我们不知道这些放大的反馈

these amplifying feedbacks will occur,

会多快发生，

it is certain they will occur,

但毫无疑问它们会发生，

unless we stop the warming.

除非我们停止让地球变暖。

There is evidence

有证据显示

that feedbacks are already beginning.

这些反馈已经开始了。

Precise measurements

重力卫星GRACE的

by GRACE, the gravity satellite,

精准测量显示，

reveal that both Greenland and Antarctica

格陵兰岛和南极都在

are now losing mass,

变小，

several hundred cubic kilometers per year.

它们每年都会缩小几百立方千米。

And the rate has accelerated

自从九年前

since the measurements began

测量开始以来，

nine years ago.

它们的缩小率都在加快。

Methane is also beginning

甲烷也开始

to escape from the permafrost.

从冻土中逃出。

What sea level rise

海平面将会

can we look forward to?

上升至什么程度？

The last time CO2 was 390 ppm,

上一次二氧化碳含量为390ppm时，

today's value,

这个含量即是现在的含量，

sea level was higher

海平面高出了

by at least 15 meters, 50 feet.

至少15米，50英尺。

Where you are sitting now

各位现在坐的地方

would be under water.

会在水下。

Most estimates are that, this century,

大多数预算表明，在本世纪，

we will get at least one meter.

海平面会上升至少一米。

I think it will be more

我认为，如果我们继续燃烧化石燃料，

if we keep burning fossil fuels,

海平面会上升更多，

perhaps even five meters, which is 18 feet,

在本世纪或此后不久，

this century or shortly thereafter.

海平面也许会上升5米，即18英尺。

The important point

问题的关键是，

is that we will have started a process

我们将开始一个

that is out of humanity's control.

超出人类控制的进程。

Ice sheets would continue to disintegrate for centuries.

冰盖将连着几个世纪持续消融。

There would be no stable shoreline.

海岸线将不再稳定。

The economic consequences are almost unthinkable.

随之而来的经济损失是不可想象的。

Hundreds of New Orleans-like devastations

全世界都会出现数百起像新奥尔良一样的

around the world.

毁灭。

What may be more reprehensible,

如果我们继续否认气候变化，

if climate denial continues,

更应受谴责的后果恐怕是

is extermination of species.

物种的灭绝。

The monarch butterfly

据气候变化政府委员会预计，

could be one of the 20 to 50 percent of all species

目前的物种中有百分之二十到五十都会在

that the Intergovernmental Panel on Climate Change estimates

本世纪末灭绝，

will be ticketed for extinction

帝王蝶就可能是

by the end of the century

其中之一，

if we stay on business-as-usual fossil fuel use.

如果我们仍像现在这样使用化石燃料。

Global warming is already affecting people.

全球变暖已经在影响我们了。

The Texas, Oklahoma, Mexico

去年发生在德州、俄克拉荷马州和墨西哥的

heatwave and drought last year,

热潮与干旱，

Moscow the year before

去年的莫斯科热潮

and Europe in 2003,

和2003年的欧洲热潮

were all exceptional events,

都是不正常的现象，

more than three standard deviations outside the norm.

这些事情的概率超过了正常值3个标准差。

Fifty years ago,

50年前，

such anomalies

这些异常现象仅

covered only two- to three-tenths

覆盖了百分之一的陆地面积的

of one percent of the land area.

十分之二到十分之三。

In recent years,

在近几年，

because of global warming,

因为全球变暖，

they now cover about 10 percent --

异常现象覆盖了约百分之十——

an increase by a factor of 25 to 50.

比以前增加了25到50倍。

So we can say with a high degree of confidence

我们可以很肯定地说，

that the severe Texas and Moscow heatwaves

发生在德州和莫斯科的严重热潮

were not natural;

是反自然的；

they were caused by global warming.

它们是由全球变暖造成的。

An important impact,

如果全球变暖持续，

if global warming continues,

我们以及全世界的食物

will be on the breadbasket of our nation and the world,

都将受到重要影响。

the Midwest and Great Plains,

中西部和大平原地区

which are expected to become prone to extreme droughts,

将变得极易干旱，

worse than the Dust Bowl,

比20世纪30年代的大沙尘暴还要严重。

within just a few decades,

如果我们继续对全球变暖不闻不问，

if we let global warming continue.

这将在几十年内就变成事实。

How did I get dragged deeper and deeper

我是如何变得越来越

into an attempt to communicate,

渴望与公众交流，

giving talks in 10 countries, getting arrested,

在10个国家演讲，被逮捕，

burning up the vacation time

耗尽我积攒了30多年的

that I had accumulated over 30 years?

度假时间？

More grandchildren helped me along.

我的孙子孙女中也有越来越多的人来帮我。

Jake is a super-positive,

Jake是一个非常积极向上、

enthusiastic boy.

热情活跃的男孩儿。

Here at age two and a half years,

他只有2岁半的时候，

he thinks he can protect

就觉得他能保护

his two and a half-day-old little sister.

他两岁半天大的妹妹。

It would be immoral

把一个持续迅速失控的

to leave these young people

气候系统

with a climate system

留给这些年轻人

spiraling out of control.

是不道德的。

Now the tragedy about climate change

而气候变化的悲剧是，

is that we can solve it

我们其实只用一个简单、诚实的办法

with a simple, honest approach

就可以解决它。

of a gradually rising carbon fee

我们可以逐步提高从化石燃料公司

collected from fossil fuel companies

收取的碳化气体排放费，

and distributed 100 percent electronically

通过电汇、依据个人收入水平

every month to all legal residents

把这次钱百分之百地分配到

on a per capita basis,

合法居民头上，

with the government not keeping one dime.

政府不拿其中一分钱。

Most people would get more in the monthly dividend

大多数人拿到的月津贴将比

than they'd pay in increased prices.

他们为上涨的物价多付的钱要多。

This fee and dividend

这笔费用和津贴

would stimulate the economy

将促进经济

and innovations,

和创新，

creating millions of jobs.

创造数以百万的工作机会。

It is the principal requirement

这是让我们

for moving us rapidly

加速进入一个清洁未来的

to a clean energy future.

主要条件。

Several top economists

几位顶级经济学家

are coauthors on this proposition.

合作提出这个主张。

Jim DiPeso of Republicans for Environmental Protection

来自环保共和党人的Jim DiPeso

describes it thusly:

因此这样形容道：

"Transparent. Market-based.

”公开透明。以市场需求为基础。

Does not enlarge government.

不扩大政府。

Leaves energy decisions to individual choices.

让公民个人为能源做决定。

Sounds like a conservative climate plan."

听起来像是一个保守的气候计划。“

But instead of placing a rising fee on carbon emissions

但是政府却没有提高碳化气体排放费，

to make fossil fuels pay

让化石燃料公司为它们带给社会的

their true cost to society,

真正危害买单，

our governments are forcing the public

却在迫使世界范围的

to subsidize fossil fuels

公民大众每年掏出

by 400 to 500 billion dollars

400到500亿美元

per year worldwide,

补贴化石燃料公司。

thus encouraging extraction of every fossil fuel --

这就鼓励化石燃料公司去挖掘每一滴化石燃料——

mountaintop removal,

切掉山顶，

longwall mining, fracking,

长壁开采，水力压裂，

tar sands, tar shale,

焦油沙，焦油页岩，

deep ocean Arctic drilling.

深海北极钻探。

This path, if continued,

如果我们继续走这条道路，

guarantees that we will pass tipping points

我们一定会超过引爆点，

leading to ice sheet disintegration

引发冰盖消融，

that will accelerate out of control of future generations.

等到了我们的后代时，消融会超出人类控制地加速。

A large fraction of species

许多物种都将

will be committed to extinction.

走向灭亡。

And increasing intensity of droughts and floods

加剧的旱灾和洪涝

will severely impact breadbaskets of the world,

将严重影响世界的食物产量，

causing massive famines

带来严重的饥荒

and economic decline.

和经济衰退。

Imagine a giant asteroid

想象一个巨大的小行星

on a direct collision course with Earth.

在和地球正面相撞的轨道上。

That is the equivalent

这和我们现在

of what we face now.

所面对的情况是相同的。

Yet, we dither,

然而，我们犹豫不决，

taking no action

却不改变

to divert the asteroid,

小行星的轨道，

even though the longer we wait,

即使我们知道我们等得越久，

the more difficult and expensive it becomes.

改变就变得更难更贵。

If we had started in 2005,

如果我们从2005年就开始改变的话，

it would have required emission reductions of three percent per year

我们需要每年减少百分之三的气体排放，

to restore planetary energy balance

才能在本世纪重造能源平衡，

and stabilize climate this century.

稳定气候。

If we start next year,

如果我们从明年开始，

it is six percent per year.

我们需要每年减少百分之六。

If we wait 10 years, it is 15 percent per year --

如果我们等上十年，就得百分之十五——

extremely difficult and expensive,

极其困难与昂贵，

perhaps impossible.

也许甚至会是不可能的。

But we aren't even starting.

然而我们到现在都没有开始。

So now you know what I know

现在你们知道了到底是什么

that is moving me to sound this alarm.

驱使我发出警告。

Clearly, I haven't gotten this message across.

显然，这个消息还没有被足够广泛地传播。

The science is clear.

科学证据再清晰不过了。

I need your help

我需要你们的帮助，

to communicate the gravity and the urgency

来更有效地传播

of this situation

情况的重要性

and its solutions

和紧急性，

more effectively.

以及解决办法。

We owe it to our children and grandchildren.

我们要对我们的后代负责。

Thank you.

谢谢大家。

(Applause)

（掌声）