What if there were 1 trillion more trees? - Jean-François Bastin

翻译人员: Yirong Chen 校对人员: Yolanda Zhang

Standing at almost 84 meters tall,

已知地球上现存的最大的一棵树，

this is the largest known living tree on the planet.

有近 84 米高，

Nicknamed General Sherman,

被亲切的称为“谢尔门将军树”。

this giant sequoia has sequestered roughly 1,400 tons of atmospheric carbon

在地球上存活的 2500 年间，

这棵巨大的红杉从大气中 吸收了将近 1400 吨的碳。

over its estimated 2,500 years on earth.

Very few trees can compete with this carbon impact,

很少有哪棵树能够 达到这样的碳影响力，

but today, humanity produces more than 1,400 tons of carbon every minute.

但是今天，人类每分钟 就会产生超过 1400 吨碳。

To combat climate change,

为了对抗气候变化，

we need to steeply reduce fossil fuel emissions,

我们需要大量减少化石燃料排放，

and draw down excess CO2 to restore our atmosphere’s balance

并且降低超量的二氧化碳， 来重建大气中的

of greenhouse gases.

温室气体平衡。

But what can trees do to help in this fight?

但是，树能在这场斗争中 起到什么作用呢？

And how do they sequester carbon in the first place?

它们又是怎样减少碳排放的呢？

Like all plants, trees consume atmospheric carbon

就像所有的植物那样，树通过 光合作用的化学反应

through a chemical reaction called photosynthesis.

从大气中吸收碳。

This process uses energy from sunlight

这个反应过程利用了太阳能，

to convert water and carbon dioxide into oxygen

将水和二氧化碳转化为氧气

and energy-storing carbohydrates.

和储存能量的碳水化合物。

Plants then consume these carbohydrates in a reverse process

然后植物通过 一个相反的过程——呼吸作用

called respiration, converting them to energy

消耗这些碳水化合物， 将它们转化为能量，

and releasing carbon back into the atmosphere.

并且将碳元素释放至大气中。

In trees, however, a large portion of that carbon isn’t released,

但是对于树来说，其中很大部分 碳元素并不会被释放，

and instead, is stored as newly formed wood tissue.

而是被储存在 新生长的木质组织中。

During their lifetimes, trees act as carbon vaults,

在它们的生命周期中， 树就像是碳储存库

and they continue to draw down carbon for as long as they grow.

并且只要它们继续生长， 就会持续吸收碳元素。

However, when a tree dies and decays,

但是，当一棵树死亡并腐烂时，

some of its carbon will be released back into the air.

一些碳元素会被释放回空气中。

A significant amount of CO2 is stored in the soil,

很大一部分二氧化碳 被储存在土壤中，

where it can remain for thousands of years.

可以存在数千年。

But eventually, that carbon also seeps back into the atmosphere.

但是最终，这一部分碳 也会渗入空气中。

So if trees are going to help fight a long-term problem

所以如果树木要成为

长期对抗气候变化问题的一员，

like climate change,

they need to survive to sequester their carbon

它们就需要存活足够长的时间

for the longest period possible, while also reproducing quickly.

进行固碳，同时要快速繁衍。

Is there one type of tree we could plant that meets these criteria?

是否有符合这些标准， 又能够人工种植的树呢？

Some fast growing, long-lived, super sequestering species

我们是否能将一些生长迅速， 寿命长且有超强固碳效应的种类

we could scatter worldwide?

种遍世界各地？

Not that we know of.

目前已知的还没有。

But even if such a tree existed,

但即使有这样一种树，

it wouldn’t be a good long-term solution.

这也不是一个理想的 长期解决方案。

Forests are complex networks of living organisms,

森林是一种错综复杂的生态体，

and there’s no one species that can thrive in every ecosystem.

没有一种特定的物种能够在 所有生态环境中繁衍。

The most sustainable trees to plant are always native ones;

适合种植且最具有可持续性的树 永远是原生品种；

species that already play a role in their local environment.

即那些在当地环境中 已有一席之地的品种。

Preliminary research shows that ecosystems

初步研究显示， 那些自然形成了

with a naturally occurring diversity of trees have less competition

树木多样性的生态体系， 对资源的竞争更少，

for resources and better resist climate change.

且能更好地应对环境变化。

This means we can’t just plant trees to draw down carbon;

这就说明，我们不能 仅靠植树去固碳；

we need to restore depleted ecosystems.

还需要重建已退化的生态环境。

There are numerous regions that have been clear cut

目前已发现，有很多地区

or developed that are ripe for restoring.

已经具备了开始重建工作的条件。

In 2019, a study led by Zurich’s Crowtherlab

2019 年，苏黎世 柯劳瑟实验室的一项研究

analyzed satellite imagery of the world’s existing tree cover.

分析了当前地球 植被覆盖的卫星图像。

By combining it with climate and soil data

并将这些图像 与气候及土壤数据结合，

and excluding areas necessary for human use,

再去除人类必要的使用区域，

they determined Earth could support

他们发现地球能够再多支撑

nearly one billion hectares of additional forest.

将近 10 亿公顷森林的生长，

That’s roughly 1.2 trillion trees.

相当于大约 1.2 万亿棵树。

This staggering number surprised the scientific community,

这个惊人的数字震撼了科学界，

prompting additional research.

并激发了更多的研究。

Scientists now cite a more conservative but still remarkable figure.

现在，科学家开始引用一个更保守， 但是仍然令人瞩目的数字。

By their revised estimates, these restored ecosystems

在修正后的预测中， 这些重建的生态系统

could capture anywhere from 100 to 200 billion tons of carbon,

能够吸收 1-2 千亿吨碳，

accounting for over one-sixth of humanity’s carbon emissions.

相当于人类碳排放量的 1/6。

More than half of the potential forest canopy

潜在的重建工程产生的 一半以上的森林覆盖

for new restoration efforts can be found in just six countries.

会分布在 6 个国家。

And the study can also provide insight into existing restoration projects,

研究也为现存的重建工程 提供了支持，

like The Bonn Challenge,

像是波昂挑战 （TheBonn Challenge），

which aims to restore 350 million hectares of forest by 2030.

它的目标是在 2030 年前完成 3.5 亿公顷森林的复育。

But this is where it gets complicated.

然而问题远没有那么简单。

Ecosystems are incredibly complex,

生态系统极其复杂，

and it’s unclear whether they’re best restored by human intervention.

并且尚不明确它们是否在 人工干涉下可以恢复得更好。

It’s possible the right thing to do for certain areas

或许对于某些地区来说，

is to simply leave them alone.

正确的方法是让它们自行修复。

Additionally, some researchers worry that restoring forests

另外，一些研究人员担心，

on this scale may have unintended consequences,

这种规模的森林复育 可能产生不可控的后果，

like producing natural bio-chemicals

比如自然生化产物的 生产速度到达一定程度后，

at a pace that could actually accelerate climate change.

可能会加速气候变化。

And even if we succeed in restoring these areas,

即使我们成功重建了这些区域，

future generations would need to protect them

后代也仍需要从

from the natural and economic forces that previously depleted them.

自然、经济等这些 传统的破坏因素中保护它们。

Taken together, these challenges have damaged confidence

综上，这些挑战已经破坏了

in restoration projects worldwide.

世界范围内重建工程的信心。

And the complexity of rebuilding ecosystems

而重建生态系统的复杂性

demonstrates how important it is to protect our existing forests.

也证明了保护我们现存的森林 是多么重要。

But hopefully, restoring some of these depleted regions

但是我们仍然希望， 重建一些已退化的区域

will give us the data and conviction necessary to combat climate change

能够在很大程度上 带给我们抗争气候变化所需的

on a larger scale.

数据和信念。

If we get it right, maybe these modern trees will have time to grow

如果我们是正确的，或许， 这些现代的大树会有足够的时间

into carbon carrying titans.

长成固碳的参天巨树。