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

譯者: Lilian Chiu 審譯者: Helen Chang

In June 2022, a gold miner in the Canadian Yukon

2022 年六月，

一名淘金者在加拿大育空

made a remarkable discovery.

有了重大發現。

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

在克朗代克火欽人的 傳統土地上工作時，

he uncovered the exceptionally well-preserved frozen remains

他發現了一些保存 非常良好的冷凍遺骸，

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

這些遺骸屬於一隻 在三萬年前死亡的小長毛象。

But this find isn’t the only of its kind

但此發現並非唯一的，

because the Arctic holds many buried secrets...

因為北極地區埋藏了許多秘密……

About 15% of the Northern Hemisphere contains permafrost—

北半球大約 15% 含有永久凍土——

that is, ground that doesn’t thaw seasonally,

永久凍土是種不會 隨季節而融化的地面，

but has instead stayed frozen for at least two years—

它們會維持凍結狀態至少兩年——

and, typically, much longer.

通常還會更長許多。

The oldest permafrost yet discovered is located in the Yukon

目前已知最古老的 永久凍土位於育空，

and has been frozen for 740,000 years.

其凍結狀態已持續了七十四萬年。

The thickness of permafrost also ranges,

各永久凍土的厚度也不盡相同，

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

厚度從僅僅一公尺 一直到一公里都有。

And permafrost is exceptionally good at preserving biological remains.

而永久凍土特別適合保存生物遺骸。

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

如果埋在永久凍土中的 遺骸周邊有冰晶，

they help draw moisture away.

它們能協助吸走水分。

And microorganisms that would otherwise quickly decompose

而有些微生物本來應該會 快速分解植物及動物組織，

plant and animal tissues operate at slower metabolic rates

若溫度不到零度，它們運作時的 新陳代謝率會變得比較低。

in these subfreezing temperatures.

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

結果就是，

不再需要仰賴化石骸骨

to extrapolate what an ancient animal might have looked like,

來推斷古代動物可能的模樣，

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

因為永凍土有時可以提供科學家

久遠時代的真實定格（凍結）畫面。

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

2016 年，另一名淘金者找到了

with a 7-week-old grey wolf pup

一隻七週大的灰狼幼崽，

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

牠被保存在永久凍土中

長達五萬七千年之久。

Researchers learned that she’d been feasting on salmon,

研究人員得知牠當時 正在吃一頓鮭魚大餐，

and think she died quickly,

並認為牠死亡的過程很快，

possibly when the den she was nestled in collapsed.

死因可能是牠居住的巢穴坍塌。

In 2020, reindeer herders encountered remains

2020年，馴鹿牧民發現的遺駭

that unmistakably belonged to a bear.

毫無疑問是屬於一頭熊。

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

但結果發現，

這些遺駭有三萬九千五百年的歷史，

They belonged to a cave bear.

是一隻洞熊的遺駭。

Its species went extinct about 24,000 years ago.

此物種在兩萬四千年前就已絕種。

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

在這之前，

科學家只見過洞熊的骨駭。

Even incomplete animal remains found in permafrost

即使在永久凍土中發現的 動物遺骸並不完整，

have yielded incredible results.

也產生了令人難以置信的結果。

In 2021, researchers identified a new species of mammoth

2021 年，

研究人員發現了一種新的長毛象，

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

靠的是用一百六十萬年前

長毛象牙齒來重建基因序列，

making it the oldest sequenced DNA on record.

使它成為記錄上最古老的 已完成序列分析之 DNA 樣本。

And extraordinary finds go beyond the animal kingdom:

在動物界之外也有一些非凡的發現：

in 2012, scientists successfully regenerated a flowering tundra plant

2012 年，

科學家成功再生了 一種開花的苔原植物，

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

靠的是他們在有三萬兩千年 歷史的松鼠洞穴中發現的種子。

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

然而，永久凍土中所有 尚未被發現的史前遺駭

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

都處於危險中，除此之外還有更多，

因為永久凍土正在迅速融化。

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

氣候變遷讓北極地區暖化的速度

是世界其他地區的三到四倍。

of the rest of the world.

And an increased frequency in extreme weather events,

且極端天氣事件的發生頻率增加，

like lightning and wildfires,

如閃電及野火，

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

會燒毀本來有助於保持 永凍土低溫的植物和土壤。

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

當永久凍土融化，

會產生令人擔憂和長遠的影響。

The ground can fracture and collapse in on itself,

地面可能會自行斷裂和坍塌，

and the landscape can experience flooding and erosion,

地面景觀則可能會遇到洪水及侵蝕，

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

讓原本穩定的樹木

也開始傾斜，形成所謂的「醉林」。

It can also trigger massive landslides and threaten critical infrastructure.

它還可能觸發大規模山崩，

威脅到重要的基礎設施。

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

到 2050 年，

永久凍土的融化可能會 危及到三百六十萬人口。

This includes many Indigenous and First Nations people

這當中包括許多原住民和第一民族，

who have lived across the Arctic region since time immemorial.

他們自古以來就一直住在北極地區。

Right now, they’re dealing with difficult decisions

而現在，他們得要做出困難的決策，

about how to protect their communities and traditional ways of life

決定在面臨氣候變遷時 要如何保護他們的

in the face of climate change.

社區和傳統生活方式。

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

融化的影響將遠遠超出北極地區。

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

這是因為永久凍土中儲存了

估計約一兆六千萬公噸的碳。

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

這是截至 2022 年地球 大氣中的碳量的兩倍多，

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

且遠超過人類因燃燒化石 燃料而釋放的所有碳量。

Permafrost is one of the world’s largest carbon reservoirs

永久凍土是世界上最大的碳庫之一，

because of all the organic material it contains—

原因是它所包含的各種有機物質——

some as intact remains,

有一些是完整的遺骸，

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

但大多數的形式都是 部分分解的土壤和沉積物。

When it begins thawing,

當它開始融化時，

microorganisms decompose organic material more efficiently,

微生物會更有效地分解有機物質，

and release gases like carbon dioxide and methane.

並釋放出二氧化碳和甲烷等氣體。

This triggers a feedback loop:

這會觸發一種回饋迴圈，

as more gases are released, the climate warms,

隨著更多氣體被釋放，氣候會暖化，

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

導致更多的永久凍土融化，

釋放出更多的溫室氣體。

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

若要保存數千年前 地球樣貌的快照——

when mammoths and cave bears trod its terrain—

長毛象和洞熊還在 地球上行走的年代——

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

以及若要維持地球未來 數千年的生命多樣性，

the Arctic needs to keep its cool.

北極地區需要好好保持它的低溫。