"Boltar" wrote in message
oups.com...
Has anyone or any research body ever done the calculations to work out
how hot the earth would have to get before a runaway greenhouse effect
kicked off?

I don't know but the risk is increasing with time as the sun gets hotter and
it will happen eventually. I've seen it suggested that the oceans will be
gone in 500 million -1 billion years time but it could be sooner giving the
right combination of circumstances.

John