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#12
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On Aug 23, 4:56 am, BDR529 wrote:
On 8/22/2010 10:26 PM, JohnM wrote: On Aug 22, 10:18 pm, wrote: On Aug 22, 7:01 pm, wrote: On 8/22/2010 6:22 PM, JohnM wrote: On Aug 22, 3:21 pm, wrote: On 8/21/2010 3:04 PM, Last Post wrote: Greenland Glacial Calving and Sea Level by Nils-Axel Mörner, Sea level specialist, Paleogeophysics& Geodynamics Nils-Axel Morner is a pathetic liar and an AGW denier. So I skipped the rest of this trash. Nevertheless, a simple contemplation of the amount of heat needed to melt the ice-cap, and the rate at which this heat can be transferred to the ice at a gradient of say 15 K, does lead one to suspect that even a thousand years might not do it. Only unprecedented rates of calving by glaciers, with rapid transport south once the bergs are in the ocean, could bring us close to a 100 year time-scale. What about the present day negative mass balance of nearly 240 km^3/yr and an acceleration of -25 km^3/yr^2 observed by satellites? I presume you meant +25 km^3 yr^-2 Just try to estimate yourself how long it will take before we really lose Greenland? Not too difficult. Greenland has an estimated 2,850,000 km^3 of ice. Loss in yr 1 = 240 ... Loss in yr 500 =240 + 25*499 ... Loss in year 1000 = 240 +25*999 Summing gives the 1,000 year loss = ca.2,500,000 in round figures. Sorry. Too late in the day to think quickly. That should be 1,250,000 in round figures, leaving ca. 1,600,000 to melt, about another 3 to 400 years worth if the acceleration keeps going. So not a millennium then, but 3 to 4 centuries from now. OUCH! snip Clearly I made this re-posting too obscure. If you had checked my arithmetic you would have seen the correction was for the additional time after the first thousand. i.e. using your current rates and acceleration it will take 1,300 to 1,400 years to melt. Should the acceleration become larger, the time will come rattling down. But I'm not going to start on speculative scenarios unless there is a lot more data about current rates. |
#13
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On 8/23/2010 8:11 PM, JohnM wrote:
On Aug 23, 4:56 am, wrote: On 8/22/2010 10:26 PM, JohnM wrote: On Aug 22, 10:18 pm, wrote: On Aug 22, 7:01 pm, wrote: On 8/22/2010 6:22 PM, JohnM wrote: On Aug 22, 3:21 pm, wrote: On 8/21/2010 3:04 PM, Last Post wrote: Greenland Glacial Calving and Sea Level by Nils-Axel Mörner, Sea level specialist, Paleogeophysics& Geodynamics Nils-Axel Morner is a pathetic liar and an AGW denier. So I skipped the rest of this trash. Nevertheless, a simple contemplation of the amount of heat needed to melt the ice-cap, and the rate at which this heat can be transferred to the ice at a gradient of say 15 K, does lead one to suspect that even a thousand years might not do it. Only unprecedented rates of calving by glaciers, with rapid transport south once the bergs are in the ocean, could bring us close to a 100 year time-scale. What about the present day negative mass balance of nearly 240 km^3/yr and an acceleration of -25 km^3/yr^2 observed by satellites? I presume you meant +25 km^3 yr^-2 Just try to estimate yourself how long it will take before we really lose Greenland? Not too difficult. Greenland has an estimated 2,850,000 km^3 of ice. Loss in yr 1 = 240 ... Loss in yr 500 =240 + 25*499 ... Loss in year 1000 = 240 +25*999 Summing gives the 1,000 year loss = ca.2,500,000 in round figures. Sorry. Too late in the day to think quickly. That should be 1,250,000 in round figures, leaving ca. 1,600,000 to melt, about another 3 to 400 years worth if the acceleration keeps going. So not a millennium then, but 3 to 4 centuries from now. OUCH! snip Clearly I made this re-posting too obscure. If you had checked my arithmetic you would have seen the correction was for the additional time after the first thousand. i.e. using your current rates and acceleration it will take 1,300 to 1,400 years to melt. Should the acceleration become larger, the time will come rattling down. But I'm not going to start on speculative scenarios unless there is a lot more data about current rates. Don't worry about the data, there is plenty from ICEsat, GRACE and SAR missions. Q |
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