Green Mars(217)
Submerging the rest of Vastitas would take about twenty more M-years, as the amount of water necessary to fill Vastitas Borealis was much greater than that needed to fill Hellas. But the pumping operation up there was bigger as well, so things were proceeding apace, and all the acts of Red sabotage combined could do no more than put a dent in this progress. In fact progress was accelerating despite increasing acts of sabotage and ecotage, because some of the new mining methods being put into use were quite radical, and very effective. The news programs showed video of the latest method, which set off big underground thermonuclear explosions, very deep under Vastitas. This melted the permafrost over large areas, providing the pumps with more water. On the surface these explosions were manifested as sudden icequakes, which reduced the surface ice overhead to a bubbling slurry, the liquid water soon freezing on the surface, but tending to stay liquid underneath. Similar explosions under the northern polar cap were causing floods nearly as vast as the great outbursts of ‘61. And all that water was pouring downhill into Vastitas.
Down at the office in Odessa, they followed all of this with professional interest. A recent assessment of the amount of underground water in the north had encouraged the Vastitas engineers to shoot for a final sea level very near the datum itself, the 0-kilometer contour that had been set back in the days of sky areology. Diana and other hydrologists in Deep Waters thought that subsidence of the land in Vastitas, as a result of the mining of aquifers and permafrost, would cause them to end up with a sea level somewhat lower than the datum. But up there they seemed confident they had factored that in, and would reach the mark.
Fooling around with various sea levels on an office AI map made it clear what shape the coming ocean was likely to have. In many places the Great Escarpment would form its southern shoreline. Sometimes that would mean a gentle slope; in the fretted terrain, archipelagos; in certain regions, dramatic seaside cliffs. Broached craters would provide good harbors. The Elysium massif would become an island continent, and the remains of the northern polar cap would as well— the land under the cap was the only part of the north well above the 0-kilometer contour.
No matter which exact sea level they chose to display on the maps, a big southern arm of the ocean was going to cover Isidis Planitia, which was lower than most of Vastitas. And aquifers in the highlands around Isidis were being pumped down into it as well. So a big bay was going to fill the old plain, and because of that, construction crews were building a long dike in an arc around Burroughs. The city was located fairly close to the Great Escarpment, but its elevation was just below the datum. It was therefore going to become a port city every bit as much as Odessa, a port city on a world-wrapping ocean.
The dike they were building around Burroughs was two hundred meters high and three hundred meters wide. Maya found the concept of a dike to protect the city disturbing, though it was clear from the aerial shots taken of it that it was another pharaonic monument, tall and massive. It ran in a horseshoe shape, with both its ends up on the slope of the Great Escarpment, and it was so big that there were plans to build on it, to make it into a fashionable Lido district, containing small boat harbors on its water side. But Maya remembered once standing on a dike in Holland, with the land on one side of her lower than the North Sea on the other side of her; it had been a very disorienting sensation, more unbalancing than weightlessness. And, on a more rational level, as news programs from Earth now showed, all dikes there were currently, stressed by a very slight rise in sea level, caused by global warming initiated two centuries before. As little as a meter’s rise endangered many of the low-lying areas of Earth, and Mars’s northern ocean was supposed to rise in the coming decade by a full kilometer. Who could say whether they would be able to fine-tune its ultimate level so accurately as to make a dike sufficient? Maya’s work in Odessa made her worry about such control, though of course they were trying for it themselves in Hellas, and thought that they probably had it. They had better, as Odessa’s location gave them little margin for error. But the hydrologists also talked about using the “canal” that had been burned by the aerial lens before its destruction, as a runoff into the northern ocean, if such a runoff became necessary. Fine for them, but the northern ocean would have no such recourse.
“Oh,” Diana said, “they could always pump any excess up into Argyre Basin.”
• • •
On Earth, riots, arson, and sabotage were becoming daily weapons of the people who had not gotten the treatment— the mortals, as they were called. Springing up around all the great cities were walled towns, fortress suburbs where those who had gotten the treatment could live their entire lives inside, using telelinks, teleoperation, portable generators, even greenhouse food, even air filtration systems: like tent towns on Mars, in fact.