Less than 20 years ago, the world's largest living structure looked like this, and this.

不到 20 年前，全世界最大的活體看起來是像這樣，和這樣。

But today, ongoing pressures from climate change put it at serious risk for being wiped out entirely.

但是現在，持續不斷的氣候變遷壓力，使得它們嚴重地面臨被完全消滅的危機。

In fact, in August, an official report by the Australian government downgraded the reef's future outlook from "poor" to "very poor."

事實上，在八月的時候，澳洲政府的官方報告將珊瑚礁的未來展望從「差的」下修到「非常差的」。

So, how exactly did we get here?

所以，我們到底是如何走到這一步的？

And can it be reversed?

這個狀況可以被翻轉嗎？

The Great Barrier Reef is big.

大堡礁很大。

So big, in fact, that you can see it from space.

事實上，它大到你可以從太空看見它。

It's important for people to remember that the Great Barrier Reef is much more than just one coral reef, which is what I think a lot of people think.

重要的是要讓人們記得，大堡礁不僅僅是一個珊瑚礁，我想很多人都這麼認為。

So, it's actually 3,000 separate, individual coral reefs, and every one of them is in a different condition.

它其實是 3,000 個各自獨立的珊瑚礁，而它們每一個的狀況都不相同。

It's also the world's largest living structure, as well as a home to thousands of plant and animal species.

它同時也是世界上最大的活體，以及數千種動植物的棲息地。

Like with trees in a forest, the corals are really the foundation of the habitat.

就像森林裡的樹木，珊瑚礁就是這個棲地的基石。

They provide the structure for other organisms to live there.

它們為其他生物體提供居住在此的結構。

A normal, healthy coral reef is very colorful.

一個正常、健康的珊瑚礁是色彩非常豐富的。

There's tons of fish swimming around.

這裡有無數種魚類在這裡悠游。

It's often quite loud underwater when you're diving on a coral reef that's healthy.

當你在健康的珊瑚礁上潛水時，水下通常是很吵鬧的。

So, you know, it's just amazing and beautiful.

所以，你知道，真的是非常令人驚艷且美麗。

But this vast ecosystem has been declining for a while.

但是這個巨大的生態系已經開始逐漸衰弱。

The culprit? Mass coral bleaching.

罪魁禍首是誰？大規模珊瑚白化。

As the name suggests, coral bleaching strips reefs of their color, leaving them completely white.

如同它的名稱，珊瑚白化會奪走珊瑚的色彩，使它們淪為一片慘白。

It happens when unnaturally warm ocean water causes coral to expel the symbiotic, colorful algae it needs to survive.

這發生在當異常溫暖的海水使珊瑚排出其生存所需的共生彩色藻類時。

Without this algae, the coral can't get the nutrients it needs and will starve to death if water temperatures don't return to normal.

沒有這種藻類，珊瑚就無法獲取所需的養分，而若是水溫沒有恢復正常，它們就會餓死。

Even small increases in temperature, when they're sustained for a long period, can be very stressful for them.

即便溫度提升幅度很小，若它們維持很長一段時間，對珊瑚而言就會非常有壓力。

It's just like a person, right?

這就像我們人一樣，對吧？

Like, you can go out into 114-degree weather for a short time and you'll be fine, but if you were to stay out there all day, you would suffer badly.

你可以在 (華氏) 114 度 (約攝氏 45 度) 的室外待一陣子，也不會怎麼樣，但如果你要在室外待一整天，你就會非常難受。

In 2016 and 2017, the Great Barrier Reef was hit with a massive marine heat wave, leading to the longest coral-bleaching events ever recorded.

2016 和 2017 年，大堡礁遭受到一股巨大的海洋熱浪侵襲，導致有史以來影響距離最長的珊瑚白化。

It devastated the reef, killing off nearly 50% of the coral.

這股熱浪徹底摧毀了大堡礁，扼殺了近百分之 50 的珊瑚。

Many corals can live for hundreds of years, so if those corals die, to get back a coral that was 400 years old and died is gonna take 400 years.

許多珊瑚可以活上數百年，因此若這些珊瑚死亡了，要復育一個死掉的 400 歲珊瑚，就需要花上 400 年。

But here's the thing.

但事情是這樣的。

This rate of bleaching is not only abnormal but completely unprecedented in the Great Barrier Reef's history.

這個白化的速度不僅僅是反常的，更是在大堡礁的歷史裡史無前例的。

We have to remember that the Great Barrier Reef is now essentially a changed ecosystem.

我們必須記得，大堡礁基本上已經是個變樣的生態系。

We've never had events as severe as those of 2016 and '17 before.

我們從未遇過如同 2016、17 年這般慘烈的狀況。

The cumulative consequence of all of that is that we don't know how well the Great Barrier Reef is going to recover from those events.

這些全部累加的後果是，我們不知道大堡礁能夠從這些事件裡回復到什麼程度。

Before the 1980s, bleaching events would occur periodically, but never on a mass scale.

在 1980 年代之前，白化事件會週期性地發生，但從未有如此大的規模。

But global warming has rapidly accelerated this process.

但是全球暖化卻急遽地加速了這個過程。

From those coral skeletal records, we know conclusively that coral bleaching is a new phenomenon.

從這些珊瑚骨骼遺骸，我們可以明確地知道珊瑚白化是一種新現象。

The first mass-bleaching event that occurred on the Great Barrier Reef was in 1982.

大堡礁第一次發生大規模的白化事件是在 1982 年。

As bleaching events are becoming more severe and more frequent, it stymies the recovery, right?

隨著白化事件發生地越來越嚴重和頻繁，這就阻礙了珊瑚復原，不是嗎？

It's almost as if you have a hurricane, you start to rebuild, and then you get hit by another one.

這幾乎就像是，你遇上了一個颶風，你開始重建，結果你又被另一個颶風侵襲。

In fact, a 2019 report by the United Nations warned that if global temperatures increased by just 0.9 degrees Celsius, which is expected to happen, coral reefs could decline by 70% to 90%.

事實上，2019 年聯合國的一份報告已經警告，只要全球的氣溫再上升攝氏 0.9 度，這已經預期會發生，珊瑚礁就會減少百分之 70 到 90。

And if it warms by 1.8 degrees, 99% of the world's coral could be at risk.

而如果溫度上升 1.8 度，百分之 99 的珊瑚都將面臨威脅。

As we approach 2 degrees of warming and go beyond 2 degrees of warming, we are probably not going to be able to protect the Great Barrier Reef anymore.

當我們逐漸接近暖化 2 度並超越暖化 2 度，我們大概再也沒有能力保護大堡礁了。

And we're actually going to lose it as the valuable ecosystem that we have.

而我們實際上將失去我們所擁有的珍貴生態系。

As if that wasn't enough, the reef is also endangered by local pollution, overfishing, and coastal development.

好像這些還不夠似的，大堡礁還受到當地污染、過度捕撈和沿岸發展的威脅。

Local management of impacts, such as pollution in runoff, sedimentation in our reefs, overfishing, these things are critically important, and they need to happen in concert with combating climate change.

地方上對於像是逕流中的污染、珊瑚礁裡的沈積物、過度捕撈，這類衝擊的管理是至關重要的，而且必須與對抗氣候變遷共同作用。

It's also important to note that the Great Barrier Reef is one of the best-managed reefs in the world.

另外也應該提到的是，大堡礁是全世界管理得最好的珊瑚礁之一。

But even with the best countermeasures, the Great Barrier Reef simply can't withstand the effects of climate change.

但即使有最好的應對措施，大堡礁仍然無法承受氣候變遷的影響。

Unless drastic international action is taken to reverse or halt greenhouse gas emissions, we might be facing a world without reefs as early as 2050.

除非採取非常猛烈的國際行動來翻轉或停止溫室氣體排放，否則最快在 2050 年我們將可能面臨一個沒有珊瑚礁的世界。

My ballpark is that if we don't do something dramatic in the next 10 years, that we will have passed the time after which there will be no return.

我的估計是，若我們不在接下來的 10 年內採取大規模的行動，我們將錯過最後的機會，再也無法回頭。

So, this all sounds pretty bad, but why should we care?

所以，這些聽起來很糟，但關我們什麼事？

What makes coral reefs so important?

珊瑚礁為什麼這麼重要？

First of all, coral reefs are an incredible source of biodiversity.

首先，珊瑚礁是極佳的生物多樣性來源。

In fact, they provide a home for 25% of all marine life even, though they take up just 1% of the ocean floor.

事實上它們提供棲地給百分之 25 的海洋生命，儘管它們只占據了海床的百分之 1。

So, we have six of the world's seven species of turtles, dugongs, whales, dolphins, seabirds, one-and-a-half thousand species of fish.

我們有全世界七種海龜中的六種、儒艮、鯨魚、海豚、海鳥和一千五百種魚類。

They're also worth billions of dollars in economic value.

他們也具有數十億美金的經濟價值。

The Great Barrier Reef alone brings in over $6 billion in tourism each year, and reefs provide a natural buffer from violent storm waves, preventing property damage and loss of life.

光是大堡礁本身每年就可以帶來超過 60 億美金的觀光收入，而且珊瑚礁可以為猛烈的風浪提供天然的緩衝，防止財產和生命的損失。

Reefs are an increasingly important resource for breakthrough medical treatments, too.

珊瑚礁也是突破性藥物治療中越來越重要的資源。

Right now, plants and animals found in coral reefs are being used to develop treatments for diseases like cancer and Alzheimer's.

現在，在珊瑚礁裡發現的動植物，正被拿來發展針對癌症或阿茲海默症等疾病的治療方法。

So, if we lose corals, we potentially lose, you know, the key to solving diseases that we care about.

所以，如果我們失去珊瑚礁，我們也可能失去治療那些我們關心的疾病的關鍵。

Not to mention, about half a billion people depend on reefs for food and work.

更不用提，有大約 5 億人的食物來源及工作都仰賴著珊瑚礁。

Even though some of the damage is irreversible, not all hope is lost for the world's coral reefs.

儘管有些傷害已無法改變，並不是全世界的珊瑚礁都失去希望了。

We as a coral reef science community are becoming increasingly focused on human intervention and, you know, basically preventing the extinction of corals and restoring reefs.

我們作為一個珊瑚礁科學團體，越來越聚關注人類干預，你知道，基本上就是防止珊瑚絕種並修復珊瑚礁。

The most important thing that we need to do is to stop and reverse climate change and global warming.

我們所要做的最重要的事，就是阻止並翻轉氣候變遷及全球暖化。