Sax stared down at his plate and ate in silence, thinking hard about all these factors. The morning’s discussions had given him cause to wonder whether he had made the right decisions back in 2042— whether the volatile inventory could justify his attempt to go straight for a human-viable surface in a single stage. Not that there was much that could be done about it now. And all things considered, he still thought they were the right decisions; shikata ga nai, really, if they wanted to walk freely on the surface of Mars in their own lifetimes. Even if their lifetimes were going to be considerably extended.
But there were people who seemed more concerned with high temperatures than breathability. Apparently they were confident that they could balloon the CO2 level, heat things tremendously, and then reduce the CO2 without problems. Sax was dubious about that; any two-phase operation was going to be messy, so messy that Sax couldn’t help wondering if they would get stuck with the 20,000-year time scales predicted in the earliest two-phase models.
It made him blink to think of it. He couldn’t see the need. Were people really willing to risk such a long-term problem? Could they be so impressed by the new gigantic technologies that were becoming available that they believed anything was possible?
“How was the pastrami?” Berkina asked.
“The what?”
“The pastrami. That’s the kind of sandwich you just ate, Stephen.”
“Oh! Fine, fine. It must have been fine.”
• • •
The afternoon’s sessions were mostly devoted to problems caused by the successes of the global warming campaign. As surface temperatures rose, and the underground biota began to penetrate deeper into the regolith, the permafrost down there was melting, just as hoped. But this was proving disastrous in certain permafrost-rich regions. One of these, unfortunately, was Isidis Planitia itself. A well-attended talk by an areologist from a Praxis lab in Burroughs described the situation; Isidis was one of the big old impact basins, about the size of Argyre, with its northern side completely erased, and its southern rim now part of the Great Escarpment. Underground ice had been creeping off the Escarpment and pooling in the basin for billions of years. Now the ice near the surface was melting, and in the winters freezing again. This thaw-freeze cycle was causing frost heaving on an unprecedented scale; it was pretty near the usual two-magnitude enlargement compared to similar phenomena on Earth, and karsts and pingos a hundred times the size of their Terran analogues were big holes, and big mounds. All over Isidis these giant new holes and hummocks were blistering the landscape, and after her talk and a sequence of mind-boggling slides, the areologist led a large group of interested scientists to the south end of Burroughs, past Moeris Lacus Mesa to the tent wall, where the neighborhood looked like it had been devastated by earthquake, the ground having heaved up to reveal a rising mass of ice like a bald round hill.
“This is a fine specimen of a pingo,” the areologist said with a proprietary air. “The ice masses are relatively pure compared to the permafrost matrix, and they act in the matrix the same way rocks do— when the permafrost refreezes at night or in winter, it expands, and anything hard stuck in this expansion gets pushed upward toward the surface. There’s a lot of pingos in Terran tundra, but none as big as this one.” She led the group up the shattered concrete of what had been a flat street, and they stared out from an earthen crater rim, onto a mound of dirty white ice. “We’ve lanced it like a boil, and are melting it and piping it into the canals.”
“Out in the country one of these coming up would be like an oasis,” Sax remarked to Jessica. “It would melt in the summer, and hydrate the ground around it. We ought to develop a community of seeds and spores and rhizomes that we could scatter on any sites like this out in the country.”
“True,” Jessica said. “Although, to be realistic, the permafrost country is mostly going to end up under the Vastitas sea anyway.”
“Hmm.”
The truth was Sax had temporarily forgotten the drilling and mining in Vastitas. When they had returned to the conference center, he deliberately looked for a talk describing an aspect of that work. There was one at four: “Recent Advances in North Polar Lens Permafrost Pumping Procedures.”
He watched the speaker’s video show impassively. The lens of ice that extended underground from the northern polar cap was like the submerged part of an iceberg, containing some ten times as much water as the visible cap. The Vastitas permafrost contained even more. But getting that water to the surface . . . like the retrieval of nitrogen from Titan’s atmosphere, it was a project so massive that Sax had never even considered it in the early years; it simply hadn’t been possible then. All these big projects— the soletta, the nitrogen from Titan, the northern ocean drilling, the frequent arrival of ice asteroids— were on a scale that Sax found he was having trouble adjusting to. They were thinking big these days, the transnationals. Certainly the new abilities in design and in materials science, and the emergence of fully self-replicating factories, were what made the projects technically feasible; but the initial financial investments were still huge.