> I think it's an unfair summary to say that Hansen is actually
> predicting a Venuslike state for the earth; he is simply speculating
> upon it under a reporter's questioning. He may be political enough to
> be reluctant to say "a runaway greenhouse won't happen". But he didn't
> say it will.
I thought that the New Scientist book review sounded not quite right,
but I have not read the book.
> "But with continued rapid increase in greenhouse gases, you could
> melt the ice sheets in less than a century".
Isn't that awfully aggressive?
He is not talking about Greenland here, but about all the world's ice,
70 metres of sea level equivalent of ice.
I have been doing some back of the envelope calculations, like to melt
70 metres of water by mixing it with sea water would require cooling
around 600 metres of water by 10C, or something of the order of three
decades worth of the complete insolation the Earth receives. Or, at
200 W per m2 just for Antarctica alone (say around 10 million square
kilometres) it would take of the order of a thousand years to melt the
ice.
What sort of scenario do you need to get the ice sheets to melt
completely in less than 100 years?
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