打破边界：我们星球的科学（2021）

to a position where it dampens and reduces the stress,
吸取二氧化碳
sucking up carbon dioxide,
吸取热量 并吸收冲击
taking up heat, absorbing impacts,
同时翻转至能够自我强化变暖的那一点
and tipping over to a point where it could self-reinforce warming
成为我们的敌人
and become a foe.
当然 气候的变暖是由温室气体造成的
The climate is, of course, being warmed by greenhouse gases,
因此正是因为排放这些气体
so it’s in our emissions of these gases
让我们发现了全球的临界点
that we find a global tipping point.
早在人类出现之前 地球的平均温度
Since long before human beings appeared, the Earth’s average temperature
就密切追踪大气中二氧化碳的浓度
was closely tracking the concentration of carbon dioxide in the atmosphere.
在全新世时期
During the Holocene,
这个浓度保持相对稳定
this concentration remained relatively steady,
（时期 年份）
但是工业革命改变了一切
but that all changed with the Industrial Revolution.
1988年 我们向地球大气层
In 1988, we passed 350 parts per million
排放了百万分之350的二氧化碳
of carbon dioxide in Earth’s atmosphere.
这是我们越过界限的时刻
This was the moment we crossed the boundary.
从那时起 我们就面临着触发导致气候
Ever since then, we’ve been at risk of triggering changes
急速变暖变化的风险
that lead to runaway warming.
如果大气中二氧化碳的浓度
You go past 350 PPM
超过了百万分之350
in the concentration of carbon dioxide in the atmosphere,
地球就进入了危险区域
and you enter the danger zone.
因此 百万分之350是约翰的第一道界限
So 350 parts per million is the first of Johan’s boundaries,
而我们已经超过了这一界限
and we’re already well beyond it.
目前 大气中二氧化碳的浓度
Right now, we’ve reached a point of carbon dioxide concentration
大约是百万分之415
in the atmosphere of roughly 415 parts per million.
我们开始看到处于
We’re starting to see the impacts of being
气候界限危险区中间的影响
in the middle of the danger zone in the climate boundary
包括旱灾、热浪和
in terms of rising frequency of droughts,
洪水的频率增加
and heatwaves, and floods,
冰块加速消融
and accelerated melting of ice,
冻土加速解冻以及森林火灾发生的频率加快
and accelerated thawing of permafrost, and higher frequency of forest fires.
上述这些是第二个临界值
Up ahead is a second threshold.
二氧化碳的浓度正在迅速接近百万分之450
We are rapidly approaching 450 parts per million carbon dioxide.
地球界限的危险区域
The planetary boundary danger zone is defined
是由科学中的不确定度范围来定义的
by the uncertainty range in science.
如今 我们的评定标准是科学中的不确定度范围
Today, our assessment is that the uncertainty range in science
在百万分之350之间
lies between 350 PPM,
这是安全区
which is the boundary
与进入危险区域之间的界限
between the safe zone and entering the danger zone,
最高为百万分之450
up to 450 PPM,
这是离开危险区域进入高风险区域的当量
which is when you exit the danger zone and go into a really high-risk zone.
考虑到临界点的迹象就在我们周围
If we enter the high-risk zone,
如果我们进入高风险区域
irreversible tipping points become highly likely, if not inevitable,
如果并非不可避免
and this is a conservative estimate,
很有可能出现不可逆转的临界点而这只是保守估计
given that the signs of tipping points are all around us now.
简单来说 气候的地球界限
In simple terms, the climate planetary boundary
相当于升温1,5摄氏度
is equal to 1.5 degrees Celsius warming,
它只是提供了所有这些证据
and it just provides all this evidence
如果我们允许自己超过1,5摄氏度 我们将承担巨大的风险
that we take a huge risk if we allow ourselves to go beyond 1.5.
我们现在在1,1摄氏度 正在迅速向1,5摄氏度迈进
We are at 1.1, we’re rapidly moving towards 1.5,
我们留在气候的地球界限内的
and our only chance to stay within the planetary boundary on climate
唯一机会在于
is that we, you know,
我们在未来30年内实现无矿物燃料的世界经济
reach a fossil-fuel-free world economy within the next 30 years.
虽然全球气温的目标可能占据了
While that target for global temperature
所有的头条新闻
may have grabbed all the headlines,
约翰知道 这只是大局的一部分
Johan knew that this was only one part of a bigger picture.
因为我们地球的稳定不单单依赖于气候
For our planet’s stability relies on more than just its climate.
必须提出更多的研究和证据
More research and evidence had to be brought forward
得出我们还有四个生物圈界限的结论
to conclude that we also have four biosphere boundaries.
这些是在生生不息的地球上的界限
Boundaries that are in the living Earth.
包括土地结构
These include the land configuration.
地球上的生物群落是如何构成的？
How… How is the composition of biomes on Earth?
三个热带雨林、温带雨林
Er, the three rain forests, the temperate forest,
北方森林
the boreal forest,
草原
the grasslands,
和湿地
the wetlands.
其次是生物多样性
Second is biodiversity.
水中和陆地上的所有物种
So all the species in water and on land.
第三是命脉与水文循环
And then the third one, of course, the bloodstream, the hydrological cycle.
淡水
最后是注入营养物质…
And then, finally, the injection of nutrients
营养物质
…这些是现存生物圈与氮磷循环
that are fundamental for the functioning of the living biosphere.
运作的基础
The nitrogen and phosphorus cycles.
第一个生物圈边界是在地球上构成的栖息地
The first of the biosphere boundaries,the composition of the habitats on Earth,
涉及到我们现在如何改造这些自然栖息地
is concerned with how we are now transforming those natural habitats.
在这个星球现存的一处最大荒野上
We are fast approaching a major tipping point
我们正在迅速接近一个重大的临界点
in one of the planet’s largest remaining wildernesses.
那就是亚马逊
The Amazon.
卡洛斯♥诺♥布雷几十年来
Carlos Nobre has been studying
一直在研究雨林对我们星球稳定性的重要之处
the rain forest’s importance to our planet’s stability for decades.
他是第一个拉响警报的人
He was the first to sound the alarm.
卡洛斯♥诺♥布雷
圣保罗大学高级研究所
我看到亚马逊在1971到1972年间并未干扰
I saw the Amazon in 1971-72 undisturbed.
我看到了森林
I saw the forest
还有河流
and the rivers.
我与食人鱼一起在尼格罗河游泳
I would swim in the Rio Negro with the piranhas,
我从没出过任何事
And nothing ever happened to me.
从那时起 亚马逊的大♥片♥土地被开垦
Since that time, large swathes of Amazon have been cleared
为畜牧业和大豆种植业提供场地
for livestock and soya farming.
卡洛斯发现 这正促使我们
Carlos has discovered that this is pushing us closer
在剩下的大部分地区触发不可逆转的改变
to triggering irreversible change across much of what remains.
1998年 我们开始在热带雨林中
In 1998, we began the largest scientific experiment
进行有史以来最大的科学实验
ever conducted in a tropical rain forest.
当时在雨林里建了很多座塔
Many towers were built in the rain forest
研究森林如何创造自己的气候
to study how it creates its own climate.
数据显示 大部分雨林正在枯竭
The data shows large parts of the rain forest are drying out.
在亚马逊 旱季最多持续三个月
In the Amazon,the dry season lasts a maximum of three months.
但是从20世纪80年代♥开♥始
But with global warming
随着全球变暖
and also forest degradation, due to human activities,
还有人类活动造成的森林退化
in particular, livestock and soya farming,
特别是畜牧业和大豆种植
the dry season has become six days longer
旱季延长了六天
each decade since the 1980s.
随着森林的减少和破坏
As the forest is reduced and fragmented,
它的循环用水
its ability to recycle water
和在旱季产生雨水的能力减弱了
and generate rain into the dry season is diminished.
如果旱季变长超过四个月
If the dry season becomes longer than four months,
丛林树木会死去取而代之的会是草原
the jungle trees die and are replaced by savanna.
这个过程称为稀树草原化
A process called savannization.
有迹象表明 亚马逊的部分地区已经在发生变化
There are signs that parts of the Amazon are already changing.
如果森林砍伐量超过森林面♥积♥的20％到25％
If deforestation goes above 20 to 25% of the forest,
随着全球变暖
with global warming increasing,
我们很可能会经历不可逆转的稀树草原化过程
we are likely to experience an irreversible process of savannization
可能影响整个亚马逊森林的50％到60％
that could affect 50 to 60% of the entire Amazon forest.
我们已经失去了近20％的亚马逊雨林
We have already lost close to 20% of the Amazon rain forest.
我们可能要把亚马逊 从地球的朋友变成地球的敌人
We could be about to tip the Amazon from planetary friend to planetary foe.
当丛林变成草原 许多树会死去
As the jungle turns to savanna, many trees die,
并将碳排放到大气中
and carbon is released into the atmosphere.
卡洛斯曾计算过 亚马逊在未来30年
Carlos has calculated the Amazon could release
将排放2000亿吨♥碳
200 billion tons over the next 30 years.
这相当于过去5年里
That’s equivalent to all the carbon emitted worldwide
全球碳排放总量
for the past five years.
我们现在非常接近临界点
We are very, very close to the tipping point.
我们是否关心应对气候危机的问题？
Are we concerned about fighting the climate crisis?
我们是否关心把碳留在森林里
Are we, er, concerned about keeping the carbon in the forest?
还是“我不在乎”？
Or “I don’t care”?
在这种时候 我们有理由深感忧虑
There is reason to be deeply concerned at this point.
我们还在把农业用地扩大到自然生态系统
We’re still expanding agricultural land into natural ecosystems.
我们对于雨林砍伐的速度
We are still cutting down the rain forest
仍在危及整个系统
at a pace that puts the whole system at risk.
而且不仅仅是雨林
And it’s not just the rain forests.