[ExI] Glacier Geoengineering
alfio.puglisi at gmail.com
Sun Jan 31 19:01:21 UTC 2010
On Sun, Jan 31, 2010 at 10:52 AM, Keith Henson <hkeithhenson at gmail.com>wrote:
> The object is to freeze a glacier to bedrock.
> The average heat flow over the entire Earth is 87 mW · m-2
> Call it 100-mW/square meter, tenth of a watt.
> A square km would have a heat flux of 100,000 watts or 100 kW
> Propane absorbs 428 kJ/kg evaporating. It boils at one atmosphere at
> -43 deg C. (Propylene boils about 10 deg colder so might use that
> So to pull 100 kW (a hundred kJ in a second) would take about 1/4 kg
> of propane per second. That's 15 kg/minute. Propane has half the
> density of water, so it would be in the range of 30 l/minute going
> down the hole. Coming back up as vapor, a cubic meter has a mass of
> about 1.9 kg/cubic meter, so 15 kg/minute would be ~eight cubic meters
> per minute, or half a cubic meter per second.
Temperatures at the glacier-bedrock interface can be amazingly high. This
article talks about bedrock *welding* with temperatures higher than 1,000
I guess the energy comes from the potential energy of the ice sliding down
This is only enough to take out the heat coming out of the earth. Probably
> need it somewhat
> larger to pull the huge masses of ice in a few decades down to a
> temperature where they would flow much slower.
If one also needs to remove the heat generated gravitationally, this could
be potentially much larger than just the Earth's heat flux.
> Glaciers cover about the same percentage of the earth as farmland. I
> don't know how much of them would have to be blocked to slow them
> down, perhaps 5-10 percent of the area.
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