Caliban

surviving image of the world would grow uglier still. “Now let me add a few supplementary graphics,” Grieg’s voice said. A series of bar charts and other displays appeared around the globe, showing the state of the forests, the sea and land biomass, temperatures, atmospheric gases, and other information.

“I will run the simulation forward at the rate of one standard year every ten seconds,” Grieg said, “and I will keep the western hemisphere positioned so you can watch the fate of Hades.” A white dot appeared at the appropriate position on the edge of the Great Bay. “That is Hades’s location.”

The governor spoke no more, but instead let the simglobe tell its own tale, partly in direct images, partly in readouts and graphic displays.

It was the oceans that died first. The predators at the top of the food chain overbred and all but wiped out the mid-chain species, the fish and other creatures that fed on each other and on the various species of plankton, and were in turn eaten by the high-end predators. Their food supply wiped out, the high-end predators died out as well.

With no controls on their reproduction, the plankton and algae in the ocean were next. They reproduced out of all control and the oceans bloomed a sickly, ghastly green. Then the seas turned brown as the algae died as well, having overrun their own food supply and absorbed virtually every molecule of carbon dioxide. With no animal life in the ocean, plant life everywhere, on land and sea, was starved for carbon dioxide. The loss of the greenhouse gas meant Inferno could retain less and less heat. The planet began to grow colder.

Alvar watched, an unwilling witness to the forthcoming doom of his own world, watched as the planet Inferno was strangled by ice. Water, water was the key. No living world could survive without it, but it could do no good— and could do great damage—if it was in the wrong state, in the wrong place. Now it was the ice cap that was the problem. The line on the chart displayed the size of the northern ice cap, but Alvar could see the cap itself growing. The ice advanced, and the northern forests fell before it, the great stands of trees dying in the too-cold, carbon- dioxide-starved air. With the atmosphere’s oxygen content far too high, and drought conditions taking hold, forest fires exploded everywhere, even as the ice pushed southward.

The white ice reflected back far more heat and light than the forests, and the planetary cooling trend locked itself in, strengthened itself, reinforced itself.

But the cooling was not universal: Alvar could see that. As the forest died and the ice advanced and the overall planetary temperature dropped, local temperatures dropped in some areas and rose in others. Wind patterns shifted. Storms grew more violent. Semipermanent snow hurricanes lodged themselves here and there along the southern coast of Terra Grande, while Purgatory became semitropical. But still the ice advanced, creeping farther and farther south, locking up more and more water in snow and ice, water that should have flowed back into the southern ocean.

The sea levels dropped. The oceans of Inferno, never very deep to begin with, receded at incredible speed as the ice grew ever deeper in the north. Islands began to appear out of the southern ocean. Still the waters drew back, until the Great Bay revealed its true form as a drowned crater. Now it was a circular sea, surrounded on all sides by land.

The ice mass continued to advance, and the city of Hades vanished under the snow and ice.

Suddenly the simulation froze. “You see this world as it will be, approximately seventy-five standard years from now. For all intents and purposes, by that time there will be no other life on this planet but ourselves. Some small remnant populations of this and that species might well survive in isolated pockets, but the world as a whole will be dead.” Alvar heard a grim graveyard chuckle in the darkness. “By the time the world is as we see it here, I suppose we humans ourselves could be regarded as a remnant in an isolated pocket.”

“I don’t understand,” Alvar protested, speaking to the faceless voice of the Governor somewhere in the dark. “I thought the danger was from the deserts growing, the planet getting too hot, the ice caps baking off.”

“That was what we all thought,” the Governor said bitterly. “Whatever desultory, token efforts my predecessor made to correct the situation were based on calculations and predictions to that effect. The deserts were supposed to grow, the ice cap to vanish completely, the sea levels to rise. There are plans in my files for dikes to be built around the city and hold back the rising water!”

Alvar heard the Governor step out from behind the console. He came around the side of the simglobe to stand by Alvar’s chair and look at the half-frozen world. “Perhaps I am being unfair. The situation is remarkably complex. If one or two variables shifted slightly, it would be the sea, and not the ice, that would overwhelm the city. In fact, stage one of our revised terraforming plan is to tip the scales back toward the collapse—into-desert, coastal-flooding scenario—it is a less drastic catastrophe than the ice age we otherwise face. You have not seen the worst of the ice age yet.”

“But why push toward the desert scenario? Why not work toward a stable middle ground?” Alvar asked.

“An excellent question. The answer is that our current situation is a result of aiming for that middle ground, a middle ground we may well not be able to achieve.”

“I don’t understand.”

The Governor sighed, his face dimly lit by the image of a dying world. “The groundwork for a stable ecology comfortable to humans was never properly laid in the first place, and we are paying the price for it. A properly terraformed world, when disturbed in some way, will always tend back toward that comfortable middle ground. Not here. Life is supposed to be a moderating factor in a planet’s environment, smoothing out the extremes. But life’s hold on Inferno is getting weaker, and a weakened system moves toward extremes. What we would view as a ‘normal’ terrestrial ecology has, on Inferno, become the abnormal, unstable transition point between two stable states—ice age or an overly arid continent with high sea levels. Of the two stable states, we are heading for the ice, and that will kill us.

“Creating an Inferno with a mostly desert, half-flooded Terra Grande may be the best we can do. It will only leave us halt and lame. You see, if we can force the trends back toward desert-spreading, then life would at least survive on this planet even when our civilization collapses!”

“When our civilization collapses!” Alvar cried out in astonishment. “What are you saying? Is that really going to happen?”

Grieg sighed, a tired-sounding noise of resignation. “I suppose I should say ‘if’ instead of ‘when,’ but I have been reading a whole series of classified reports that suggest that collapse is far more likely than anyone imagines. When it gets bad, people will start pulling out. Not everyone will be able to afford it. There will be too few ships available. Prices will be high. Some people will die, and many more will leave. I doubt there will be a large enough population left to keep society functioning, even with the robots. Maybe all the people will die off, but the robots will survive. Who knows?”

The Governor seemed to come back to himself a bit. He drew his shoulders up and looked down at Alvar and spoke in a firmer, more controlled voice. “Forgive me. There is a great deal on my mind.”

Chanto Grieg paced back and forth in front of Alvar once or twice, clearly working to collect his thoughts. At last he spoke. “We are in a knife-edge situation, Sheriff, in more ways than one. Political and social issues are intertwined with the ecological problems. In looking at the ecology, we therefore must plan for the likelihood that whatever survivors there are will not be able to do anything to save the planet, beyond whatever efforts we make. The ice age result is not survivable. The desert result is. So we force the planet back toward the desert pattern, and, if we get the chance, we can try and reterraform from there. That will certainly be preferable to our current future,” Grieg said, gesturing toward the simglobe.

“But the ice age doesn’t look that bad,” Alvar objected.

“Don’t forget that I have stopped the program,” Grieg said. “But yes, all this, we could survive, even if we ignore the great and terrible crime of allowing the planet to die.” The Governor regarded the globe thoughtfully. “Even the ice overwhelming the city is not an insurmountable problem, viewed on a global scale. We could dome over the town, or burrow underground, as the Settlers do. But this is not the end of the story.”

The Governor turned and stepped back into the darkness. Alvar heard the Governor tapping new commands into the console, and found himself struck by the random thought that buttons and switches were a typically Settler way to do things. Why not voice commands, or an interface to allow a robot to handle the machinery?

But he knew his mind was just finding ways to avoid facing the reality of what Grieg was showing him. What does all this have to do with me? he wondered, more than a bit uncomfortably. I’m just a cop chasing crooks. I’m not running the planet. But even as he told himself those things, Alvar knew there was a larger reality here. And all this might well have a great deal to do with