万物简史 第622期:冰河时代(19)

（单词翻译）

On the other hand, the next phase of our history could see us melting a lot of ice rather than making it. If all the ice sheets melted, sea levels would rise by two hundred feet—the height of a twenty-story building—and every coastal¹ city in the world would be inundated². More likely, at least in the short term, is the collapse³ of the West Antarctic ice sheet. In the past fifty years the waters around it have warmed by 2.5 degrees centigrade, and collapses⁴ have increased dramatically. Because of the underlying⁵ geology of the area, a large-scale collapse is all the more possible. If so, sea levels globally would rise—and pretty quickly—by between fifteen and twenty feet on average.

另一方面，在我们历史的下一阶段，将会看到大量冰盖融化而不是大量冰盖形成。如果所有的冰盖都融化，海平面将上升60米——有20层楼那么高，全世界所有沿海城市都会被淹没。更加可能的是，至少在短期内，南极洲西部的冰盖会塌陷。在过去50年的时间内，南极洲周围水域的温度增加了2.5摄氏度，冰盏塌陷已经大大加剧。这一地区的地质构造特点使得大规模的塌陷更有可能发生。一旦这种情况出现，全球海平面将平均上升——而且速度很快——4.5—6米。

The extraordinary fact is that we don't know which is more likely, a future offering us eons of perishing frigidity⁶ or one giving us equal expanses of steamy heat. Only one thing is certain: we live on a knife edge.

一个明显的事实是，我们不知道未来的年代是一个严寒气候，还是一个酷热的气候。只有一点是肯定的，我们生活在刀刃上。

In the long run, incidentally, ice ages are by no means bad news for the planet. They grind up rocks and leave behind new soils of sumptuous⁷ richness, and gouge⁸ out fresh water lakes that provide abundant nutritive possibilities for hundreds of species of being. They act as a spur to migration⁹ and keep the planet dynamic. As Tim Flannery has remarked: "There is only one question you need ask of a continent in order to determine the fate of its people: ‘Did you have a good ice age?' " And with that in mind, it's time to look at a species of ape that truly did.

顺便提一句，从长远来看，冰川期对于地球绝不是一件坏事。冰川磨碎岩石，留下新的肥沃的土壤；它们开凿出淡水湖泊，为数以百计的生物种类提供丰富的养分；它们推动了动植物的迁移，使得地球充满生机。正如提姆·弗兰纳里所说：“要想确定某一块陆地上的人类的命运，你只需问问那块大陆这样一个问题：‘有过一个像样的冰川期吗？'”记住这一点，我们接着该看一看有一种类人猿是怎样应对这种变化的。