I see that the press is waking up to the speed of the collapse of arctic sea ice. Anyone who has read my earlier posts will not be very surprised. My surprise is the ongoing bafflement of the scientific community. Then again these are the guys who dodged physics as fast as they could.
It takes a long time for a mass of deep frozen ice to warm back up to the melt temperature. While this is happening, melting is modest. But once all the ice is potential melt (i.e. 32 degrees) then it gallops. On top of that the ice is steadily thinning so that the available mass is declining in a non linear manner.
For example, if the removal rate is 5% of the original mass M then we have the following effect:
year 1 .95M
year 2 .90M equals 5.26%
year 3 .85M equals 5.55%
year 4 .80M equals 5.88%
year 5 .75M equals 6.25%
year 6 .70M equals 6.66%
year 7 .65M equals 7.14%
You see were this is going. The point is that the surface area has dropped from 5m to 3m in the past thirty years and the actual mass has dropped by at least 60%. The truth is that this has mostly happened over the last half of that time period. This suggests that the removal rate has been around 3% of the original maximum ice cover and it is now in the last stages of removal and collapse.
I wrote three years ago that I would be brave and say that the sea ice would be flushed out by 2015 when everyone was saying 2100. I am beginning to think that I was too conservative. We need a cold spell up there.
It takes a long time for a mass of deep frozen ice to warm back up to the melt temperature. While this is happening, melting is modest. But once all the ice is potential melt (i.e. 32 degrees) then it gallops. On top of that the ice is steadily thinning so that the available mass is declining in a non linear manner.
For example, if the removal rate is 5% of the original mass M then we have the following effect:
year 1 .95M
year 2 .90M equals 5.26%
year 3 .85M equals 5.55%
year 4 .80M equals 5.88%
year 5 .75M equals 6.25%
year 6 .70M equals 6.66%
year 7 .65M equals 7.14%
You see were this is going. The point is that the surface area has dropped from 5m to 3m in the past thirty years and the actual mass has dropped by at least 60%. The truth is that this has mostly happened over the last half of that time period. This suggests that the removal rate has been around 3% of the original maximum ice cover and it is now in the last stages of removal and collapse.
I wrote three years ago that I would be brave and say that the sea ice would be flushed out by 2015 when everyone was saying 2100. I am beginning to think that I was too conservative. We need a cold spell up there.
Be happy.
Tim Flannery at the IAI conference said that the melting ice water falls to the bottom of the ice sheet and "lubricates" the movement of the ice. This has resulted in several (frequent) major shifts of ice; giving earthquake readings of 3(?)-4.5.
ReplyDeleteHe said Norwegian (?) scientists reported that the sea ice did not freeze this year for the first time (aerial inspection)
Flannery also said that if the whole ice sheet does move we would hear it in Australia !!
With all this this melting you would expect N hemisphere waters to be colder than S.H.
They are not; Southern Oceans are colder than Northern. Thus dissolving more CO2 in S Oceans; thus also dissolving the Great Barrier Reef. Some scientists only give it 10-20 years (Catalyst ABC TV)