CLIMATE change has always been driven by the sun, the earth’s orbit and plate tectonics, at least that is what many so-called sceptic would argue.
In a new paper in this week’s journal Nature Tim Naish and colleagues conclude that there is a relationship between the past collapse of West Antarctic ice shelf and the earth’s orbit. In the same issue of Nature there is an article by David Pollard who, with Robert De Conto, ran a five-million-year computer simulation of the ice sheet and concluded that if surrounding waters increase by 5 degrees Celsius, it could melt in one thousand years or so.
So, the loss of the West Antarctic ice shelf from warming is a thing to worry about on a thousand-year, rather than hundred-year, time frame.
Add to this new information suggesting that Greenland’s once galloping glaciers have slowed, and it seems there is going to need to be a reduction in the official estimates of sea level rise which have been fairly modest anyway – modest at least relative to claims by Al Gore.
Modelling West Antarctic Ice Sheet Growth and Collapse Through the Past Five Million Years. David Pollard and Robert M DeConto. Nature Vol 458, March 19, 2009
Obliquity-paced Pliocene West Antarctic ice sheet oscillations. Tim Naish et al, Nature Vol 458, March 19, 2009
Heaven and Earth by Ian Plimer http://jennifermarohasy.com/blog/2009/03/heaven-and-earth-new-book-by-ian-plimer/