世界会以冰封终结吗？

Here are some ways the world might end in ice, according to science fiction. Earth freezes. Humankind’s remnants huddle in ice caves, fend- ing off giant alien monsters (Snowball Earth). Or people shelter in the New York Public Library as ice encases the Empire State Building (The Day After Tomorrow). Or a train hurtles in an endless loop, both protection and prison for Earth’s scant survivors (Snowpiercer). These stories are all set in Earth’s near future, within a decade from now. And what makes the visions so chilling is that there’s a snowflake of truth in them. Well, space mon- sters haven’t invaded Earth — yet. …