Maybe it was a story of researchers finding a frozen baby mammoth in some permafrost.

也許是研究人員在永久凍土層中發現一隻冰凍的猛獁象寶寶的故事。

Or you might have heard about the risk of it melting and releasing some long, dormant supervirus.

或者，你可能聽說過它有可能融化並釋放一些長期休眠的超級病毒。

But there's a good chance permafrost is not exactly what you picture in your head.

但很有可能永凍土並不完全是你想象中的樣子。

It's not just a layer of ice and snow.

這不僅僅是一層冰雪。

It's the frozen remains of ancient ecosystems.

這是遠古生態系統的冰凍遺蹟。

And in some cases, it's the foundation of modern ones.

在某些情況下，它還是現代建築的基礎。

It's actually pretty complex, and there are a lot of reasons to care about it.

它其實很複雜，有很多理由讓我們關心它。

Because a ton of it is about to melt.

因為有一大堆即將融化。

And if it does, it's going to have a massive impact on the entire planet.

如果真的發生了，它將對整個地球產生巨大的影響。

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In simple terms, permafrost is soil in the ground that stays frozen year-round for at least two years straight.

簡單地說，永久凍土就是地面上至少連續兩年終年冰凍的土壤。

But there's so much more to it than that.

但事情遠不止這些。

While permafrost often includes lots of rock and ice, the key ingredient is organic matter.

雖然永久凍土通常包括大量岩石和冰，但關鍵成分是有機物。

So when you hear about animal bodies being found in permafrost, they aren't, like, frozen in an ice cube.

所以，當你聽說在永久凍土層中發現動物屍體時，它們並不是被凍在冰塊裡。

It's more like being mummified in frozen mud.

這更像是在冰凍的泥漿中變成木乃伊。

All that organic matter, and the carbon atoms within it, are what make permafrost so important for the entire planet.

所有這些有機物和其中的碳原子，正是永凍土對整個地球如此重要的原因。

As a plant grows, it takes carbon dioxide out of the atmosphere and stores it in its roots, stalk, and leaves.

植物在生長過程中會從大氣中吸收二氧化碳，並將其儲存在根、莖和葉中。

When the plant dies and decomposes, a lot of that carbon ends up going right back into the atmosphere as carbon dioxide, or worse, methane.

植物死亡和腐爛後，大量的碳最終會以二氧化碳或更糟糕的甲烷的形式回到大氣中。

But what if you stuck that plant in a freezer before it had a chance to decompose?

但是，如果你在植物還沒來得及腐爛之前就把它放進冰箱呢？

You'd trap all of its carbon in the freezer, too.

你也會把它的碳都困在冰箱裡。

That's why permafrost is a carbon sink, something that pulls carbon out of the atmosphere.

這就是永凍土是碳匯的原因，它能從大氣中吸收碳。

It stops the decomposition process in its tracks.

它能阻止分解過程的進行。

That is, until it melts.

也就是說，直到它融化為止。

Once things warm up, microbes break down all that organic matter and release carbon dioxide and methane.

一旦氣溫升高，微生物就會分解所有有機物，釋放出二氧化碳和甲烷。

And methane is an even worse greenhouse gas than carbon dioxide because it traps so much more heat.

而甲烷是比二氧化碳更糟糕的溫室氣體，因為它能捕獲更多的熱量。

Over a century, methane warms the planet up to 30 times more than CO2.

一個世紀以來，甲烷使地球變暖的程度是二氧化碳的 30 倍。

You can probably see the issue here.

你大概可以從這裡看出問題所在。

If the Earth warms up, permafrost melts and releases greenhouse gases that warm the Earth even more, melting more permafrost, and so on.

如果地球變暖，永久凍土融化，釋放出溫室氣體，使地球更加變暖，融化更多的永久凍土，如此循環。

Even more concerning, Earth's poles are warming about twice as fast as the rest of the planet.

更令人擔憂的是，地球兩極的變暖速度是地球其他地區的兩倍。

Which is where you can find the vast majority of our permafrost.

我們絕大多數的永久凍土都在這裡。

There are 14 million square kilometers of it across northern Europe,

整個北歐有 1 400 萬平方公里、

Alaska, and the Canadian and Russian Arctic.

阿拉斯加以及加拿大和俄羅斯的北極地區。

Like, you can find permafrost under 15% of the land in the Northern Hemisphere.

比如，你可以在北半球 15%的土地下發現永久凍土。

And all of that permafrost stores about twice as much carbon as is in our atmosphere today.

所有這些永久凍土所儲存的碳大約是我們今天大氣中碳含量的兩倍。

There's also some permafrost in the Southern Hemisphere, and even some undersea permafrost, mostly in the Arctic Ocean.

南半球也有一些永久凍土，甚至還有一些海底永久凍土，主要在北冰洋。

So it's a lot more widespread than you'd think.

是以，它比你想象的要廣泛得多。

Permafrost may evoke an image of barren, lifeless tundra, but that's another misconception.

永凍土可能會讓人聯想到荒蕪、毫無生機的凍原，但這是另一種誤解。

It can form the base of thriving ecosystems like boreal forests that grow on peatlands.

它可以構成繁榮的生態系統的基礎，如生長在泥炭地上的北方森林。

And plants growing on permafrost are really helpful since they provide insulation and shade to prevent the ice from thawing.

生長在永久凍土層上的植物非常有用，因為它們可以提供隔熱和遮陽效果，防止冰層解凍。

So when a wildfire comes along and burns down all the plants, permafrost ends up melting even after the blaze is out.

是以，當野火出現並燒燬所有植物時，永久凍土甚至會在大火熄滅後融化。

Not from the heat of the fire, but from the ground staying warmer without the forest to shade it.

不是因為火的熱量，而是因為沒有森林遮擋的地面更暖和了。

A 2023 study in Alaska looking for hot spots of methane emissions from melting permafrost found that they were nearly a third more likely in areas where wildfires had burned through even 50 years prior.

2023 年在阿拉斯加進行的一項研究尋找永久凍土融化產生的甲烷排放熱點，發現即使在 50 年前，在野火燒過的地區，甲烷排放的可能性也要高出近三分之一。

And a warmer planet means more intense wildfires, which will just keep this cycle going.

地球變暖意味著野火更加猛烈，這將使這種循環繼續下去。

By now, you've probably figured out that this is more than just some frozen ground, but permafrost is also more than just one thing.

現在，你可能已經明白，這不僅僅是一些冰凍的地面，但永久凍土也不僅僅是一種東西。

One of the coolest kinds of permafrost is called yedema, and it's utterly crucial when it comes to carbon storage.

最酷的一種永久凍土被稱為 "酵母凍土"，它在碳儲存方面至關重要。

Yedema is a massive permafrost layer that stretches across Siberia, Alaska, and Canada.

葉德瑪是橫跨西伯利亞、阿拉斯加和加拿大的巨大永久凍土層。

It can be up to 130,000 years old, but all of it dates back to the last ice age, so all of it is at least 10,000 years old.

它的歷史可能長達 13 萬年，但所有這些都可以追溯到上一個冰河時期，是以所有這些都至少有 1 萬年的歷史。

Over the last two centuries, yedema has been the subject of much debate among scientists.

在過去的兩個世紀中，水腫一直是科學家們爭論不休的話題。

They first used the term to describe permafrost that was particularly rich in ice.

他們首先用這個詞來形容冰量特別豐富的永久凍土。

In fact, scientists would find massive chunks of ice buried in the ground next to things like woolly mammoths.

事實上，科學家們會在長毛猛獁象等動物旁邊發現埋在地下的大塊冰塊。

So their question was, how did that ice get there?

是以，他們的問題是，冰塊是如何到達那裡的？

It took a hot minute to figure out how these ice wedges formed, but now researchers have a pretty good idea.

研究人員花了很長時間才弄清這些冰楔是如何形成的，但現在已經有了一個相當不錯的想法。

In the cold Arctic winter, the ground contracts, forming small cracks across it.

在北極寒冷的冬天，地面會收縮，形成遍佈地面的小裂縫。

These cracks then fill up with water from melting snow and other runoff, which freezes when it flows down and reaches the cold permafrost.

這些裂縫會被融化的雪水和其他徑流填滿，水流到寒冷的永久凍土層時就會結冰。

Water is one of the few substances that expands when it freezes, so the growing ice widens the cracks ever so slightly.

水是為數不多的在結冰時會膨脹的物質之一，是以不斷增大的冰會使裂縫變得越來越寬。

Every year, this seasonal cycle repeats, and the ice wedges grow into massive columns of ice.

每年，這種季節性循環都會重複，冰楔逐漸長成巨大的冰柱。

From ground level, these look like a network of large polygons, but below this, ice wedges in yedema can be more than 40 meters deep.

從地面上看，這些地方就像一個由大型多邊形組成的網絡，但在其下方，水腫的冰楔可能有 40 多米深。

In addition to being ice-rich, yedema is also carbon-rich.

除了富含冰之外，葉德曼還富含碳。

See, because it formed during the last ice age, the carbon froze really quickly and didn't have much chance to decompose first.

因為它是在上一個冰河時期形成的，所以碳很快就凍結了，沒有機會先分解。

Not all of this carbon would be released in the atmosphere if the layer melted, but around 10% could be.

如果碳層融化，這些碳不會全部釋放到大氣中，但大約有 10%的碳會釋放到大氣中。

And the fact that yedema is perforated by all these ice wedges turns out to have a pretty devastating downside.

而事實上，水腫被所有這些冰楔穿孔，會帶來非常嚴重的負面影響。

When those ice wedges melt, they destabilize the surrounding permafrost.

當這些冰楔融化時，就會破壞周圍永久凍土層的穩定。

The ground collapses, creating voids that are now exposed to air, perfect conditions for organic material to decompose and release greenhouse gases.

地面塌陷產生的空隙現在暴露在空氣中，是有機物分解和釋放溫室氣體的絕佳條件。

One computer model suggests that by the year 2300, greenhouse gas emissions from all types of permafrost will be about as much as humans emitted up to the year 2000.

一個計算機模型顯示，到 2300 年，各類永久凍土的溫室氣體排放量將與人類截至 2000 年的排放量相當。

And while there's a lot of uncertainty around the exact number, we know permafrost can emit a lot of greenhouse gas.

雖然確切數字還存在很多不確定性，但我們知道永久凍土可以釋放大量溫室氣體。

It's yet another reason why it's so important for us humans to reduce our carbon emissions as soon as possible and prevent these feedback loops.

這也是為什麼我們人類必須儘快減少碳排放，防止這些反饋循環的另一個原因。

So now you know what permafrost is and what it isn't, which is good, since it's going to play a pretty big role in our planet's future, and research suggests we should do what we can to preserve it.

現在你知道什麼是永久凍土，什麼不是永久凍土了吧，這很好，因為永久凍土將在我們地球的未來扮演重要角色，研究表明我們應該盡我們所能來保護它。

With any luck, this Arctic oddity will be around long enough to be misunderstood by generations to come.

如果運氣好的話，這個北極奇觀還能存在很長時間，以至於被後人誤解。

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