How are these fires burning underground? - Emma Bryce

譯者: Ng Kai Yuan 審譯者: Esther Lam

In 1997, a fire began in Indonesia that would rage for almost a year.

1997 年，印度尼西亞發生了 一場火災，持續燃燒將近一年。

It spanned several thousand square kilometers,

蔓延至數千平方公里，

halted numerous international flights,

許多國際航班因此停駛，

and spread an acrid haze all the way to China.

陣陣刺鼻的烟霧甚至彌漫到中國。

Yet, despite being one of the largest fires in recorded history,

然而，儘管這是記錄史上最大的火災之一，

for months at a time it burned without a flame—

大火在好幾個月的時間內都沒有火焰，

blazing on entirely underground.

它是在地底下燜燒。

This might sound like a uniquely freaky fire, but each year,

這似乎是一場離奇反常的火災，但每年，

subterranean fires produce roughly 15% of global greenhouse gas emissions—

地下火災大約排放了全球15%的溫室氣體，

that’s six times more than international aviation.

這可是國際航空業排放量的六倍。

And these burns are virtually unstoppable,

而且這些火災幾乎無法撲滅，

earning them the ominous title of zombie fires.

贏得了殭屍火災的恐怖稱號。

So, is it possible to snuff out these bizarre blazes?

那麼，是否有可能熄滅 這些奇怪的火焰？

And how do they even form in the first place?

而且，它們究竟是如何形成的？

A standard fire requires three ingredients: fuel, heat, and oxygen.

一場普通的火災需要三個要素： 燃料，熱能和氧氣。

Every fuel has what’s known as an ignition point—

每種燃料都有所謂的燃點

a temperature at which it begins to break down.

即燃料開始分解的溫度。

This process, also known as pyrolysis,

這個過程也稱為熱裂解，

releases gaseous compounds that mix with nearby oxygen molecules

釋放出氣體化合物， 這些化合物與附近的氧氣分子結合，

to produce combustion.

從而產生燃燒。

And it’s this chemical reaction that releases large amounts of heat and light

正是這種化學反應， 以火焰形式

in the form of flames.

釋放大量的熱與光。

But not all combustion leads to flames.

但並非所有的燃燒都會產生火焰。

Pyrolysis leaves behind a solid material called char—

熱裂解會留下被稱為炭的 固體物質

like what’s found in charcoal.

就像木炭中含有的那種物質。

Char contains no combustible gases but it’s rich in highly flammable carbon.

炭不含可燃氣體，但富含易燃的碳元素。

And under hot enough conditions,

在足夠高的溫度下，

its surface reacts with the surrounding oxygen,

其表面與周圍的氧氣發生反應，

creating a slow, glowing burn called smoldering.

形成一種緩慢而發光的燃燒，稱為燜燒。

Instead of flame, this process releases smoke;

這個過程釋放的是煙， 而不是火焰

specifically, smoke full of emissions like carbon monoxide, methane,

特別是包含一氧化碳、甲烷

and particulate matter.

和顆粒物的煙霧。

All these factors come into play in zombie fires,

所有的這些因素， 在殭屍火災中都發揮作用，

which are more scientifically known as peat fires.

這種火的學名為泥炭火。

Peat is a type of soil that forms when organic matter builds up more rapidly

當有機物質堆積的速度 超過其分解速度時

than it decomposes,

便會形成泥炭這種土壤。

and it’s typically found in regions that are very cold or very wet—

通常出現在十分寒冷或潮濕的地區

two factors that can slow down decomposition.

這兩個因素都能減緩分解的速度。

When plants shed and die in peatland,

當植物在泥炭地中枯萎和死亡時，

the carbon they've absorbed during their lifetime gets locked inside,

牠們一生中所吸收的碳， 將被保管在泥炭地裡，

making peatlands one of the planet's largest natural carbon stores.

使得泥炭地成為地球上最會 儲存碳的天然倉庫之一。

But just like char, that also makes this carbon-rich material extremely flammable.

但就如炭一樣，這種富含 碳的物質也非常易燃。

Historically, the moisture and cold temperatures of peatlands

以往，泥炭地的潮濕和寒冷的溫度

made them unlikely to catch fire.

不太可能發生起火事故。

But today, droughts caused by climate change

但如今，氣候變化引起的乾旱

are drying out these landscapes worldwide,

正在使全球各地的泥炭地乾燥化，

and other peatlands have been drained to make way for farms.

而有些已經被瀝乾， 以騰出作為農業用地。

Under these conditions,

在這種情況下，

a fire at the surface can more easily ignite the peat below,

表層上的火能夠更容易地 點燃下方的泥炭，

transforming it into char which will continue to smolder.

將其轉化為炭， 使其繼續燜燒。

As heat builds in the soil, it further dries the peat

隨著土壤中的熱量積聚， 泥炭將越來越乾燥

and eventually, deeper layers begin to burn.

最終深層的部分開始燃燒。

Peat fires are slow, creeping along at just one millimeter a minute.

泥炭火災蔓延的速度緩慢， 每分鐘的速度只有一毫米。

But what they lack in speed, they make up for in persistence.

但是速度上缺乏的， 將透過持久性來彌補。

These fires can burn for months or even years,

這些火焰可以燃燒數月甚至數年，

all while spewing smoke full of poisonous gases.

同時噴出充滿毒氣的煙霧。

And since they show few signs of burning above ground,

由於地面上很少露出燃燒的跡象，

they’re incredibly difficult to track until they ignite dry surface soil,

除非它們開始點燃乾燥的土壤表面， 不然要追蹤源頭是非常困難的，

potentially miles away from the source.

更何況源頭可能有數英里遠。

Zombie fires can even burn beneath snow-caked soil,

殭屍火災甚至可以在 積雪的土壤下燃燒，

overwintering until they spark new blazes in the spring.

過冬，直到春天來時再次引發新的火災。

So how can we fight these fires?

那麼？我們該如何對抗這種火災？

Well, dousing them with water is surprisingly tricky.

出乎意料的是 灌水撲滅沒設想中的簡單。

Water's molecules form close bonds,

水分子會緊密相結合，

resulting in a high surface tension that stops it from filtering evenly

形成高度表面張力，

through burning peat.

阻止其均勻滲透到燃燒的泥炭中。

Researchers are experimenting with ways to reduce water’s surface tension,

研究人員正在實驗 降低水表面張力的方法，

allowing it to permeate the simmering soil.

使水能夠滲透到持續燃燒的土壤中。

And some countries are trying to stop the fires before they start

有些國家試圖在災難開始前， 阻止火災的發生，

by running controlled burns in peatland habitats.

透過在泥炭地進行控制燃燒。

But many others are simply working to prevent peatland drainage,

而多數則是致力於預防泥炭地的排水，

which keeps these landscapes wet and resilient to fires.

使這些地保持濕潤，抵禦火災。

Despite accounting for only 3% of Earth's land,

儘管泥炭地只佔地球土地的3%，

peatlands hold more than a quarter of the planet's carbon.

其佔有的碳， 是地球的四分之一以上。

And as climate change continues to increase the risk of extreme weather,

隨著氣候變化持續增加極端天氣的風險，

including the droughts plaguing these landscapes,

包括對這些地區構成威脅的乾旱，

keeping that carbon out of the atmosphere has never been more important.

防止這些碳進入大氣層的工作， 比以往任何時候都更加重要。