Sixty days and counting - Kim Stanley Robinson [94]
What they had found this last summer was that all Antarctic temperatures, in air, water, and ice, had risen, and this was allowing melt water on the surface of the WAIS to run down holes and cracks, where it froze and split the ice around it further. When this “water wedging” reached all the way through the ice it poured down and pooled underneath, thus floating the broken ice a bit and lubricating its slide into the sea.
Why the ice streams moved so much faster than the surrounding ice was still not fully understood, but some were now postulating under-ice watersheds, where melt water was flowing downstream, carrying the ice over it along. This would explain why the ice streams were now acting more like rivers than glaciers. There were different hydrodynamics resulting in different speeds.
Diane interrupted the two glaciologists making the report before they got too deep into the mysteries of their calling. “So what kind of sea-level rise are we looking at?” she asked. “How much, and when?”
The glaciologists and the NOAA people looked around at each other, then made a kind of collective shrug. Frank grinned to see it.
“It’s difficult to say,” one finally ventured. “It depends so much on stuff we don’t know.”
“Give me parameters then, and your best bets.”
“Well, I don’t know, I’m definitely getting out of my comfort zone here, but I’d say as much as half of the ice sheet could detach in the next several years. That would be down the middle on the Ross Sea side, where there’s a big trough under Ice Stream B. All that could flood and the ice get tugged away. Here, and here,” red-lighting the map like a kid waving a penlight, “are under-ice ranges connecting the Peninsular Range and the Transantarctics, and those create catchment basins which will probably anchor a good bit of these regions,” making big red circles. Having made his ignorance disclaimer, he was now carving the map like a geography teacher. Diane ignored this discrepancy, as did everyone else; it was understood that they were now guessing, and that his red circles were not data, but rather him thinking aloud.
“So—that implies what, a couple-few meters of sea-level rise?”
“A couple.”
“So, okay. That’s pretty bad. Time scales, again?”
“Hard to say? Maybe—if these rates hold—thirty years? Fifty?”
“Okay. Well…” Diane looked around the room. “Any thoughts?”
“We can’t afford a sea-level rise that high.”
“Better get used to it! It’s not like we can stop it.”
They turned with renewed interest to Frank’s suggestion of flooding the world’s desertified lake basins. The discussion went over the parts of an informal NSF study which suggested that big salt lakes would indeed cause clouds and precipitation downwind, so that watersheds to the east would receive more water. Local weather patterns would change with the general rise in humidity, but as they were changing anyway, the changes might be hard to distinguish from the background. Ultimate effects impossible to predict. Frank noted how many studies were coming to that conclusion. Like all of them, when it came to weather. It was like nerve damage.
They looked at each other. Maybe, someone suggested, if that’s what it takes to save the seacoasts from flooding, the global community would compensate the new lakes’ host nations for whatever environmental damage was assessed. Possibly a sea water market could be established along with the carbon market; possibly they could be linked. Surely the most prosperous quarter