What happens when the Arctic permafrost melts? - Brendan Rogers and Jessica Howard

翻译人员: Yip Yan Yeung 校对人员: Gia Hwang

In June 2022, a gold miner in the Canadian Yukon

2022 年 6 月，加拿大 育空地区的一名淘金者

made a remarkable discovery.

获得了一个重大发现。

While working on the traditional lands of the Tr’ondëk Hwëch’in First Nation,

他在第一民族传统领地 Tr’ondëk Hwëch’in 工作时，

he uncovered the exceptionally well-preserved frozen remains

发现了保存非常完好的冰冻遗骸，

of a woolly mammoth calf that died 30,000 years ago.

来自死于三万年前的 长毛猛犸象幼崽。

But this find isn’t the only of its kind

但是这个发现绝非个例，

because the Arctic holds many buried secrets...

因为北极还埋藏着许多秘密……

About 15% of the Northern Hemisphere contains permafrost—

北半球大约 15% 的面积 包含永冻层——

that is, ground that doesn’t thaw seasonally,

即土地不会随着季节融化，

but has instead stayed frozen for at least two years—

而是保持至少两年的冻结状态，

and, typically, much longer.

通常会更久。

The oldest permafrost yet discovered is located in the Yukon

现今发现最古老的永冻层 位于育空地区，

and has been frozen for 740,000 years.

已经冻结了 74 万年。

The thickness of permafrost also ranges,

永冻层有厚有薄，

from just 1 meter in some areas to over a kilometer in others.

有些地区只有 1 米厚， 而有些地区厚达 1 千米。

And permafrost is exceptionally good at preserving biological remains.

永冻层很适合保存生物遗骸，

If any ice crystals are close to remains buried in permafrost,

一旦冰晶靠近 埋于永冻层中的遗骸，

they help draw moisture away.

永冻层会把水分排开。

And microorganisms that would otherwise quickly decompose

于是往常快速分解 动植物组织的微生物

plant and animal tissues operate at slower metabolic rates

会在这样低于冰点的温度下 以更缓慢的速度进行代谢，

in these subfreezing temperatures.

The outcome is that, instead of having to rely on fossilized skeletons

这会导致我们不再需要 通过骨架化石

to extrapolate what an ancient animal might have looked like,

推测古动物可能长什么样，

permafrost can sometimes offer scientists literal freeze-frames of times long gone.

永冻层有时可以为科学家们 提供万年以前的实况定格画面。

In 2016, another gold miner came face-to-face

2016 年，另一名淘金者

with a 7-week-old grey wolf pup

迎面挖到了一头 7 周大的灰狼幼崽，

that had been preserved in permafrost for 57,000 years.

已在永冻层中保存了 5.7 万年。

Researchers learned that she’d been feasting on salmon,

研究人员发现 她在大吃三文鱼，

and think she died quickly,

认为她死得很快，

possibly when the den she was nestled in collapsed.

有可能是因为她所在的狼窝塌了。

In 2020, reindeer herders encountered remains

2020 年，驯鹿牧人

that unmistakably belonged to a bear.

发现了明确属于一头熊的遗骸。

But it turned out that they were as much as 39,500 years old.

结果发现遗骸可追溯到 超过 3.95 万年以前，

They belonged to a cave bear.

属于一头洞熊。

Its species went extinct about 24,000 years ago.

洞熊已在大约 2.4 万年前灭绝，

Before this, scientists had only ever seen cave bear skeletal remains.

在此之前，科学家只发现过 洞熊的骨骼遗骸。

Even incomplete animal remains found in permafrost

即使永冻层中发现的 动物遗骸不完整，

have yielded incredible results.

还是带来了惊人的成果。

In 2021, researchers identified a new species of mammoth

2021 年，科学家发现了 一种新的猛犸象，

by reconstructing DNA sequences from 1.6-million-year-old mammoth teeth—

由 160 万年前的猛犸象牙齿 重构 DNA 序列，

making it the oldest sequenced DNA on record.

成为有史以来最古老的DNA测序记录。

And extraordinary finds go beyond the animal kingdom:

重大发现不仅限于动物领域：

in 2012, scientists successfully regenerated a flowering tundra plant

2012 年，科学家成功复现了 一种开花的苔原植物，

from seeds they found encased in 32,000-year-old squirrel burrows.

来源于 3.2 万年前的 松鼠洞中保存的种子。

However, all the prehistoric remains we have yet to discover in permafrost

但是，我们尚未发现的 所有永冻层中的史前遗骸

are at risk, along with much more, because permafrost is thawing rapidly.

都岌岌可危，且日渐恶化， 因为永冻层正在快速融化。

Climate change is warming the Arctic at 3 to 4 times the rate

气候变化正在使北极升温，

速度比世界其他地区快 3-4 倍。

of the rest of the world.

And an increased frequency in extreme weather events,

极端气候事件越发频繁地发生，

like lightning and wildfires,

如闪电和山火，

is burning the plants and soil that otherwise help to keep permafrost cool.

烧掉了本该保持永冻层 低温的植物和土壤。

When permafrost thaws, it has concerning and far-reaching effects.

永冻层融化时，会产生 令人担忧且深远的影响。

The ground can fracture and collapse in on itself,

地面会裂开、向内塌陷，

and the landscape can experience flooding and erosion,

整块区域会发生洪涝和侵蚀，

making previously stable trees tilt and form so-called “drunken forests.”

让原本稳固的树木倾斜， 形成所谓的“醉林”。

It can also trigger massive landslides and threaten critical infrastructure.

还会造成大规模的山体滑坡， 威胁重要的基础设施。

By the year 2050, permafrost thaw may endanger 3.6 million people.

到 2050 年，永冻层融化 会危及 360 万人。

This includes many Indigenous and First Nations people

包括许多原住民和第一民族人，

who have lived across the Arctic region since time immemorial.

他们从远古时期起 就住在北极地区各处。

Right now, they’re dealing with difficult decisions

眼下，他们正面临艰难的决定：

about how to protect their communities and traditional ways of life

如何在气候变化面前 保护他们的族群和传统的生活方式。

in the face of climate change.

The effects of thawing will also extend far beyond the Arctic.

解冻的后果远远超出了北极自身，

This is because permafrost stores an estimated 1.6 trillion tons of carbon.

这是因为永冻层储存了 大约 1.6 万亿吨的碳，

That’s over double the amount in Earth’s atmosphere as of 2022—

这比 2022 年地球 大气层内的碳多不止一倍，

and more than humans have ever released by burning fossil fuels.

比人类燃烧化石燃料至今 产生的总碳量还多。

Permafrost is one of the world’s largest carbon reservoirs

永冻层是世界上最大的碳库之一，

because of all the organic material it contains—

因为它含有的所有有机物质——

some as intact remains,

有的是完整的遗骸，

but much of it in the form of partially decomposed soils and sediments.

但很多是已部分分解的土壤和沉淀物。

When it begins thawing,

永冻层一开始融化，

microorganisms decompose organic material more efficiently,

微生物就会更高效地 分解有机物质，

and release gases like carbon dioxide and methane.

然后释放出二氧化碳 和甲烷这样的气体。

This triggers a feedback loop:

这就形成了一个循环：

as more gases are released, the climate warms,

释放了更多气体， 气候变得更暖，

causing more permafrost to thaw and release even more greenhouse gases.

造成了更多永冻层融化， 释放出更多的温室气体。

To preserve snapshots of what the planet was like thousands of years ago—

如果我们想保留 地球万年以前的定格瞬间——

when mammoths and cave bears trod its terrain—

那时，猛犸象和洞熊 在它们的家园里漫步，

and to support the diversity of life on Earth thousands of years to come,

如果我们想为地球未来万年里的 生命多样性做出贡献，

the Arctic needs to keep its cool.

那么，北极必须维持它的低温。