超级火山,人类灭绝的最大威胁?

A Giant Volcano Could End Human Life on Earth as We Know It
超级火山，人类灭绝的最大威胁？

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.
如果你打算在这个劳动节周末去黄石国家公园，我有个好消息：你在公园期间，公园下面的超级火山喷发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.
黄石超级火山在过去210万年里喷发过三次，最近一次是在64万年前。人类历史上还没有经历过黄石火山喷发。

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.
首先是越来越强烈的地震，表明黄石公园地下的岩浆正向地表涌去。然后，岩浆会在巨大的喷发中冲破地面，将有毒的地球内部物质排放到空气中。这将持续数天，将黄石公园埋在40英里半径内的熔岩中。

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.
公园里糟糕的一天。但是围绕公园的破坏仅仅是个开始。火山学家认为，黄石国家公园的超级火山爆发将把科罗拉多、怀俄明和犹他州的大片地区掩埋在高达三英尺的有毒火山灰中。中西部的相当部分地区也会降落几英寸的火山灰，从而陷入一片黑暗，具体取决于天气情况。随着火山灰云的扩散，即使是大多数美国人居住的沿海地区也极有可能出现灰尘。农作物将被摧毁；牧场会受到污染。电线和电力变压器将被破坏，可能导致相当大面积的停电。

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."
这还只是美国。气象学家建立的模型发现，如果喷发是在夏季，释放出来的气雾可能会扩散到全球。在短期内，由于有毒云团阻挡阳光，全球平均气温可能会大幅下降，并在数年内无法恢复正常。降雨量将急剧下降。这可能足以引发热带雨林灭绝。从中西部开始，农业可能会崩溃。一组研究人员在2015年为欧洲科学基金会(European Science Foundation)撰写的关于极端地质灾害的报告中写道，这将是“自文明诞生以来最大的灾难”。

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.
像黄石这样的超级火山构成了所谓的生存风险——可能导致全球毁灭、甚至人类灭绝的超级灾难。这种风险可以是天灾，比如超级火山爆发，或者是造成恐龙灭绝那种级别的小行星撞击地球；也可能是人祸，比如核战争或工程改造病毒。它们绝对比人类经历过的最糟糕的事情还要糟糕。然而，它们并不常见——这就构成了一个重大的心理和政治挑战。

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.
虽然小行星备受媒体和迈克尔·贝(Michael Bay)电影的关注，但生存风险专家们在很大程度上同意，超级火山才是人类灭绝的最大自然威胁，地球上分布着20座超级火山。但是危险性绝对不高。黄石公园在任何一年里发生超级喷发的概率是73万分之一。

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.
但非常不可能并不等于完全不可能，尽管人类的天性就是把两者混为一谈。将生存风险与日常危险区分开来的不是可能性，而是后果。

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.
假设正如科学家们所建立的模型，一次超级喷发可能会杀死全球10%的人口。即使这样的火山爆发大约每71.4万年发生一次——这属于较低的频率——灾难造成的死亡人数相当于从现在到超级火山最终爆发那一年，平均每年死亡超过1000人。如果火山喷发大约每4.5万年发生一次——也就是以较高的频率——那么预计的每年死亡人数将跃升至1.7万人左右。

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.
做点横向比较会有帮助。2018年，全球航空事故造成556人死亡。仅美国联邦航空管理局(Federal Aviation Administration)每年就在航空安全方面支出逾70亿美元。然而，美国每年在火山灾害项目上的开支仅为2200万美元，尽管从长远来看，超级火山造成的死亡人数将远远超过飞机失事造成的死亡人数。

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.
当然，不同之处在于，航空带来的风险是相对恒定且已知的。可能每一年都会有人死于航空事故，但绝对不会有哪一年，全球10%的人口死于一次空难。然而，一旦遭遇超级火山爆发、小行星撞击或核战争，这种情况就有可能发生。

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.
我们可以减少这些生存风险。美国国家航空航天局(NASA)每年在行星防御方面的预算为1.5亿美元，并可能投资太空望远镜，捕捉我们现在忽略的小行星。将世界其他地区的火山监测提升到与美国相同的水平，每年需要大约3.7亿美元，这将减少超级火山爆发带来的意外，从而降低潜在死亡人数。当然，预防核战争、甚至人工智能等人为的生存风险，这完全在我们的能力范围之内。我们这个物种面临着比以往任何时候都更大的生存危险，但与人类存在的大多数时期不同，我们现在已经有能力保护自己。

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.
以前发生的事情最终可能再次发生，也一定会再次发生——但由于我们仍然局限于自身经历的短暂的人类时间范围内，我们将它们视为不现实的。这样一来，我们就无从面对我们无法想象的东西。