超級火山,人類滅絕的最大威脅?大綱

A Giant Volcano Could End Human Life on Earth as We Know It

超級火山，人類滅絕的最大威脅？

If you're planning to visit Yellowstone National Park this Labor Day weekend, I have good news: It is very, very, very unlikely that the supervolcano beneath it will erupt while you're there.

如果你打算在這個勞動節週末去黃石國家公園，我有個好消息：你在公園期間，公園下面的超級火山噴發的可能性非常非常小。

The Yellowstone supervolcano — an 8 out of 8 on the Volcanic Explosivity Index — has erupted three times over the past 2.1 million years, most recently 640,000 years ago. A Yellowstone eruption would be like nothing humanity has ever experienced.

黃石超級火山在過去210萬年裏噴發過三次，最近一次是在64萬年前。人類歷史上還沒有經歷過黃石火山噴發。

First would come increasingly intense earthquakes, a sign that magma beneath Yellowstone was rushing toward the surface. Then magma would burst through the ground in a titanic eruption, discharging the toxic innards of the earth to the air. It would continue for days, burying Yellowstone in lava within a 40-mile radius.

首先是越來越強烈的地震，表明黃石公園地下的岩漿正向地表涌去。然後，岩漿會在巨大的噴發中衝破地面，將有毒的地球內部物質排放到空氣中。這將持續數天，將黃石公園埋在40英里半徑內的熔岩中。

A bad day at the park. But the devastation around Yellowstone would be just the beginning. Volcanologists believe a Yellowstone supereruption would bury large swaths of Colorado, Wyoming and Utah in up to three feet of toxic volcanic ash. Depending on the weather patterns, much of the Midwest would receive a few inches, too, plunging the region into darkness. Even the coasts — where a majority of Americans live — would most likely see a dusting as the ash cloud spread. Crops would be destroyed; pastureland would be contaminated. Power lines and electrical transformers would be ruined, potentially knocking out much of the grid.

公園裏糟糕的一天。但是圍繞公園的破壞僅僅是個開始。火山學家認爲，黃石國家公園的超級火山爆發將把科羅拉多、懷俄明和猶他州的大片地區掩埋在高達三英尺的有毒火山灰中。中西部的相當部分地區也會降落幾英寸的火山灰，從而陷入一片黑暗，具體取決於天氣情況。隨着火山灰雲的擴散，即使是大多數美國人居住的沿海地區也極有可能出現灰塵。農作物將被摧毀；牧場會受到污染。電線和電力變壓器將被破壞，可能導致相當大面積的停電。

That's just the United States. Modeling by meteorologists has found that the aerosols released could spread globally if the eruption occurred during the summer. Over the short term, as the toxic cloud blocked sunlight, global average temperatures could plunge significantly — and not return to normal for several years. Rainfall would decline sharply. That might be enough to trigger a die-off of tropical rain forests. Farming could collapse, beginning with the Midwest. It would be, as a group of researchers wrote in a 2015 report on extreme geohazards for the European Science Foundation, "the greatest catastrophe since the dawn of civilization."

這還只是美國。氣象學家建立的模型發現，如果噴發是在夏季，釋放出來的氣霧可能會擴散到全球。在短期內，由於有毒雲團阻擋陽光，全球平均氣溫可能會大幅下降，並在數年內無法恢復正常。降雨量將急劇下降。這可能足以引發熱帶雨林滅絕。從中西部開始，農業可能會崩潰。一組研究人員在2015年爲歐洲科學基金會(European Science Foundation)撰寫的關於極端地質災害的報告中寫道，這將是“自文明誕生以來最大的災難”。

Supervolcanoes like Yellowstone represent what are known as existential risks — ultra-catastrophes that could lead to global devastation, even human extinction. They can be natural, like supereruptions or a major asteroid impact of the scale that helped kill off the dinosaurs, or they can be human-made, like nuclear war or an engineered virus. They are, by definition, worse than the worst things humanity has ever experienced. What they are not, however, is common — and that presents a major psychological and political challenge.

像黃石這樣的超級火山構成了所謂的生存風險——可能導致全球毀滅、甚至人類滅絕的超級災難。這種風險可以是天災，比如超級火山爆發，或者是造成恐龍滅絕那種級別的小行星撞擊地球；也可能是人禍，比如核戰爭或工程改造病毒。它們絕對比人類經歷過的最糟糕的事情還要糟糕。然而，它們並不常見——這就構成了一個重大的心理和政治挑戰。

Though asteroids get the press and the Michael Bay movies, existential risk experts largely agree that supervolcanoes — of which there are 20 scattered around the planet — are the natural threat that poses the highest probability of human extinction. But that's not the same thing as high. The probability of a supereruption at Yellowstone in any given year is 1 in 730,000.

雖然小行星備受媒體和邁克爾·貝(Michael Bay)電影的關注，但生存風險專家們在很大程度上同意，超級火山纔是人類滅絕的最大自然威脅，地球上分佈着20座超級火山。但是危險性絕對不高。黃石公園在任何一年裏發生超級噴發的概率是73萬分之一。

But extremely unlikely isn't the same thing as impossible, even though it's human nature to conflate the two. What sets existential risks apart from everyday dangers isn't likelihood but consequence.

但非常不可能並不等於完全不可能，儘管人類的天性就是把兩者混爲一談。將生存風險與日常危險區分開來的不是可能性，而是後果。

Let's say, as scientists have modeled, that a supereruption might kill 10 percent of the global population. Even if such eruptions occur roughly every 714,000 years — the low end of the frequency range — the death toll of that catastrophe equates to the expected loss of over 1,000 people annually, averaged out between now and when that supervolcano finally blows. If they occur roughly every 45,000 years — the high end of the range — that annual expected death toll jumps to some 17,000.

假設正如科學家們所建立的模型，一次超級噴發可能會殺死全球10%的人口。即使這樣的火山爆發大約每71.4萬年發生一次——這屬於較低的頻率——災難造成的死亡人數相當於從現在到超級火山最終爆發那一年，平均每年死亡超過1000人。如果火山噴發大約每4.5萬年發生一次——也就是以較高的頻率——那麼預計的每年死亡人數將躍升至1.7萬人左右。

A bit of comparison helps here. Aviation accidents around the world caused 556 deaths in 2018. The Federal Aviation Administration alone spends more than $7 billion a year on aviation safety. Yet the United States spends only about $22 million annually on its volcano hazard programs — even though supervolcanoes, viewed over the longest of the long term, will kill far more people than plane crashes.

做點橫向比較會有幫助。2018年，全球航空事故造成556人死亡。僅美國聯邦航空管理局(Federal Aviation Administration)每年就在航空安全方面支出逾70億美元。然而，美國每年在火山災害項目上的開支僅爲2200萬美元，儘管從長遠來看，超級火山造成的死亡人數將遠遠超過飛機失事造成的死亡人數。

The difference, of course, is that aviation poses a risk that is relatively constant and known. There will probably never be a year in which no one dies in an aviation accident, but there will definitely never be a year in which 10 percent of the global population dies in a single plane crash. Yet that could happen with a supervolcano, an asteroid strike or a nuclear war.

當然，不同之處在於，航空帶來的風險是相對恆定且已知的。可能每一年都會有人死於航空事故，但絕對不會有哪一年，全球10%的人口死於一次空難。然而，一旦遭遇超級火山爆發、小行星撞擊或核戰爭，這種情況就有可能發生。

We can reduce these existential risks. NASA has budgeted $150 million a year on planetary defense and could invest in space-based telescopes that might catch the asteroids we're missing now. It would cost about $370 million a year to bring the rest of the world up to the same level of volcanic monitoring that the United States has, which would lessen the chance of being surprised by a supereruption and thus reduce the potential death toll. Human-made existential risks like nuclear war or even artificial intelligence are, of course, well within our ability to prevent. Our species faces greater existential peril than we ever have before, but unlike through most of our existence, we now have the ability to protect ourselves.

我們可以減少這些生存風險。美國國家航空航天局(NASA)每年在行星防禦方面的預算爲1.5億美元，並可能投資太空望遠鏡，捕捉我們現在忽略的小行星。將世界其他地區的火山監測提升到與美國相同的水平，每年需要大約3.7億美元，這將減少超級火山爆發帶來的意外，從而降低潛在死亡人數。當然，預防核戰爭、甚至人工智能等人爲的生存風險，這完全在我們的能力範圍之內。我們這個物種面臨着比以往任何時候都更大的生存危險，但與人類存在的大多數時期不同，我們現在已經有能力保護自己。

What has happened before can and will happen again, eventually — but because we remain confined to the brief human time horizons of our own experience, we treat them as unreal. In doing so, we leave ourselves vulnerable to what we can't imagine.

以前發生的事情最終可能再次發生，也一定會再次發生——但由於我們仍然侷限於自身經歷的短暫的人類時間範圍內，我們將它們視爲不現實的。這樣一來，我們就無從面對我們無法想象的東西。