Time of the Great Freeze

Time of the Great Freeze, Robert Silverberg, Holt Rinehart & Winston, 1964

In the year 2600, Earth has been in an ice age for the past couple of hundred years. Jim Barnes is a teenage resident of New York City, which is actually several miles under the ice. Learning that the ice is starting to recede, is part of a small group that has made radio contact with London. For unknown reasons, London sounds less than overjoyed at the thought of visitors from New York.

The group is forced to quickly turn their talk of an expedition to London into reality. In the space of a few hours, they are arrested, tried, convicted of treason and exiled to the surface (with appropriate supplies). It seems that hundreds of years of no contact with any other cities have made New Yorkers (or, at least, their rulers) very mistrustful of foreigners.

The expedition is helped by a pair of solar-powered jet sleds. Along the way, the group runs into several groups of wandering nomads, some of whom are more civilized than others. Having spent their lives underground, eating synthetic protein, they have a hard time eating raw meat from a freshly killed animal. Jim "convinces" a sea captain to take them across the open water of the Atlantic (the only way they can get to London) by using his knowledge of judo to defeat the captain in hand-to-hand combat.

Eventually, they are met by a delegation from London, who have come to meet them. New York's rulers don't have a monopoly on distrust and paranoia. Does the entire group make it to London? Can both groups start to regain trust in outsiders?

This story might seem rather simplistic, but remember when it was published, long before Young Adult fiction became popular. It is still worth reading for young people, or those who are new to science fiction.