“As you can see, it’s much harder to perturb something out of a low-point balance, and it will tend to return to its balance point once a perturbation is removed. Now, a Polar Sea would move the global climate into a stable low- point system that would require massive effort to dislodge into instability.
“As I have said, the problem is the absence of water circulation in the northern hemisphere. If there were a way to let water accumulate in the northern polar regions, while providing inlets and outlets to the Southern Ocean, then warm water could flow north to warm the poles, and cold water could come south to cool the ocean—and the land areas near the coast. That would give us a low-point balance, where the natural force working on the planet would be self-correcting. If things got too hot, the cold polar waters would cool them off. If the temperatures dropped too much, tropical waters would warm them up. We need water over both poles.”
“But there are a number of terraformed planets without water on both poles,” Fredda objected. “And I recall, even Earth had one pole with land on it—and the other with highly restricted water flow. I think the pole with water on it was even frozen over most of the time.”
Lentrall smiled again, and it was not a warm or friendly expression. Rather, it was the debater’s smile of triumph, something close to a condescending sneer. She had fallen into the trap he had laid, and now he could move in for the kill. “I have answers to all that,” he said. “I think you will find that they all strengthen my argument. Regarding the terraformed planets with land-locked poles, I can tell you that all of them have bodies of water that get much closer to the poles than we have on Inferno.”
“What about the examples she cited from Earth?” Kresh asked.
“First, the natural oceans of Earth were far deeper than the artificial oceans of any terraformed planet,” Lentrall said. “Because they were deeper, they held much more water and served as a much more effective heat sink.
“Second, they covered far more of the surface of the planet than on most terraformed worlds. Three-fourths of Earth was water. Slightly less than two-thirds of Inferno’s surface is water, and it has more water coverage than any other wholly terraformed world. The difference between three-fourths and two-thirds may not sound like much, but it is substantial—and, as I have said, measured by volume, and not surface area, Inferno’s oceans are much smaller than Earth’s.
“Third, even if Earth’s oceans did not have free and open access to either pole, once again, they reached close enough to allow substantial heat exchange.
“Fourth, the land-locked South Pole of Earth was far colder than the water-covered North Pole, which just goes to show my point that liquid water served to moderate temperatures. While the surface of the Arctic Ocean was frozen over, there were still a lot of water—and a lot of water currents—below the ice.
“Finally, Earth’s climate was remarkable for its instability. It suffered severe ice ages, which were triggered by very small fluctuations in this variable or that. There is substantial evidence that the impeded flow of water over the poles was a major contributing factor to this instability. I would submit that all of these facts regarding Old Earth strengthen, rather than weaken, the argument in favor of a water flow over the North Pole.”
“Hmmph.” Fredda didn’t trust herself to say anything more. The infuriating thing was that the man was right. He did marshal his arguments well. But there was so much in his tone, in his attitude, in his behavior, that made her want to disagree with him, made her want to argue with him, tooth and nail.
“Go on, Dr. Lentrall,” said Alvar, his voice an absolute study in neutrality. “What is your backing for all this?”
“An excellent question, Governor,” Lentrall said, in a tone of voice that made it sound as if he were praising a bright schoolboy. “As you are no doubt aware, the original terraforming plans for Inferno called for the creation of just such a Polar Sea. I have derived most of my information from those old studies.”
“Why did they cancel the plans for the Polar Sea?” Fredda asked.
“Partly it was politics and scheduling. Building the Polar Sea would have slowed the whole project up for years, and there was pressure to land colonists on the planet as soon as possible. By that time, a great number of things had already gone wrong with the terraforming project. There was some thought given to abandoning the planet altogether. Costs were getting out of control. But that would have done terrible damage to Spacer pride and prestige. The engineers were ordered to complete the project, but they were not given the time or the resources or the money to do it properly. They really had no choice but to cut corners. And the Polar Sea was one they could cut. Not doing it freed up enough resources to let them complete the rest of the terraforming project.”
“A generous interpretation,” said Kresh. “I’ve studied the old files and reports as well. I’d say they didn’t come close to completion of the terraforming project. What they did was declare that they had completed it. The terraformers of Inferno knew exactly the mess they were creating. I found at least three reports predicting a planetary climate collapse—and all three predicted that it would happen right about now, give or take a few years.”
Lentrall looked annoyed at Kresh for interrupting the flow of his speech. “In any case, the original planning documents clearly call for establishing a substantial flow of water in and over the polar regions. All of their projections showed that it would moderate and stabilize the planetary climate, as well as increasing rainfall throughout Terra Grande.”
“Pretty big job, digging an ocean,” Fredda said. Lentrall smiled again, and the expression didn’t make her like him any more. “Yes it is,” he agreed. “But most of the work has been done for us already. Kaelor, bring me my map case.”
Lentrall’s robot came forward. It opened a storage compartment in the front of its torso, drew out a long, thin tube, and handed the tube to Lentrall. Lentrall opened the tube and pulled out a map printed on glossy stock. “This shows the north polar regions of Inferno,” he said, spreading the map out on the low table in front of him. “One of the features of the Infernal landscape that we tend not to notice is that it is rather heavily cratered. Part of the reason for this is that the original settlers chose city sites in the regions with the lightest crater cover. Besides which, most of the craters are heavily eroded. But most of Terra Grande—and most of the flooded lowlands that now make up the ocean floor—are quite heavily cratered.”
Lentrall stabbed a finger down on the exact center of the map. “As you can see, a pair of very large overlapping craters sit astride the North Pole, a formation generally known as the Polar Depression. You will note two things about the Depression. One, that nearly all of the land area inside it is below sea level. Two, there are actually permanent icecaps inside the craters. Those icecaps used to be seasonal in nature. They are now permanent, and they are growing. Every year during northern summer they melt back a bit—but every winter the storms deposit more snow, and the icecaps grow more than they have shrunk. More and more of the planet’s fresh water is being locked up at the north pole. If there were a channel bringing in warm tropical water, it would melt back the icecaps in short order. If a channel could be opened from the Southern Ocean to the Polar Depression, the waters would rush in, forming the Polar Sea.”
“What you’re saying is that we have a ready-made seabed,” said Fredda, “and it is already partly filled with water-frozen water, but water all the same. Which means that all we have to do is dig the channel.”
“Not a simple matter, or a small one,” Kresh said. “And there would either have to be two channels dug, or one channel large enough to encompass both a northward and southward flow.”
“We’d need both, actually,” Lentrall said. “One channel that could accommodate two-way flow, and one that would simply serve as a sort of huge pressure-relief valve. The second outlet would not generally carry huge amounts of water, but it would make it possible to regulate the amount of water in the Polar Sea.”
“How do manage to get water to flow in two directions at once through one channel?” Fredda asked.
“Actually, that is one of the more straightforward parts of the business,” said Lentrall. “It happens all the time in natural oceans. The warm water moves on top, while the counterflow of cold water moves on the bottom. A sort of natural temperature barrier, or thermocline, develops. The two currents are quite distinct from each other. They can even have different concentrations of trace elements. For all intents and purposes, they do not intermix. In the present case, the cold counterflow to the south should also serve to scour out the initial channel through the process of water erosion.”
“You make it all seem so simple,” said Fredda, not making any great effort to keep the sarcasm out of her voice. “Why it is it no one has ever thought of it before?”
But Lentrall was clearly immune to sarcasm, no doubt because he was virtually unable to detect it. “Oh, many people have thought of it before,” he said. “The problem is that no one has been able to find a way to go about digging the necessary channels until now. The job was too big and too expensive to do with any conceivable sort of conventional digging equipment. If we started right now, with an all-out effort to dig the channel, we
