Long before Lord Valentine’s Castle and the world of Majipoor, Robert Silverberg practiced envisioning memorable worlds with Time of the Great Freeze.

Sometime in the 23rd or 24th century, our solar system passes through a dense cloud of interstellar dust, a veil sufficient to interfere with the sunlight we depend upon for warmth. The effect is neither dramatic nor sudden, but nonetheless certain. The snows of winter melt later and later each year, at last failing to retreat even at the height of summer. Year after year the snows accumulate and press down layer upon layer, a freeze that eventually brings the restless seas to a standstill and covers the land in ice a mile and more deep.

It has happened before.

In these days of concern about global warming, it is sobering to realize that -regardless of current human actions- the Earth may still be in nothing more than an inter-glacial period. The forces that have caused four major ice ages over two and half billion years may well be beyond anything over which our influence holds sway. (Technically, with Greenland and Antarctica covered by ice, we are yet to fully leave the last ice age, which largely receded about 11,000 years ago. At the height of Earth’s long “summers,” the planet is ice free, even at high latitudes.)

So one day, the cold will surely return.

In the Time of the Great Freeze, the new ice age has been at its height for centuries, and a few cities have retreated build far underground, with populations but shadows of their once great namesakes, like New York and London.

The residents of these cities are swept up in an authoritarian paranoia, with dissent an intolerable crime. Their world is their world, the city that keeps them safe. Should contact come from another city, it can be seen only in shades of threat and danger, the intention perhaps of stealing power, supplies, or food.

And so eight men from New York are banished from the city for even attempting radio contact with London. Sent up to the world of ice with a few supplies and a pair of solar powered sleds, they decide to forge on to London, more than 3,000 miles across the frozen sea.

The characters in Time of the Great Freeze are not as well drawn as those Robert Silverberg would later prove himself capable, but the world of the ice becomes a character of its own. What made its impression on me was the way in which three of the adventurers die suddenly, mercilessly, with only a moment’s regret evident from their fellow travelers.

One loses his life at the point of a spear thrown by hostile surface dwellers, another falls through a crack in the ice to be swept away by the hidden sea, and a third dies of a food borne illness. In each case, the world claims its victim; the adventurers pay their toll to move on.

In the end, reaching London provides no rescue, as the Englishmen sent to the surface to meet our heroes are under orders to kill them as spies.

The story moves along quickly, introducing us to a world in which the generations left to survive alone on the ice have learned to do so with no more than bone tools and animal sinews. The moose graze on glacial lichen, wolves stalk after the weakest of the herd, and man survives on anything he can. The glaciers have become an unrelenting desert of ice.

Scattered tribes present a variety of outlooks, from animal savagery to being honor bound in providing assistance to any strangers who may pass by, while in the once equatorial zones new nations have arisen to carry on the science and civilization that once dared to touch the stars.

Novels that make us aware of the vastness of space are one thing, but I appreciate here the depth of time. In our day to day lives we have lost all sense of it. Our current civilization even denies its existence. Emotionally, most of us look back a few thousand years and conceive that as the beginning of time. In reality, it is barely the first soft stirring of human memory, and all we know has little weight beyond the half forgotten dreams of morning.  The births and deaths of mountains are but the passing of a breath in deep time.

This is the type of science fiction I grew up on: interesting ideas presented in the guise of a grand adventure. It is memorable for leaving us feeling we have braved the cold and glimpsed an age in which everything precious to us has been transformed by ice, a world in which the highest towers of New York shall not melt free until a time equivalent to all of recorded history passes by once, and then perhaps yet again.