[LINK] o/t End of Days

[David Boxall]

On 22/07/2011 2:21 PM, stephen at melbpc.org.au wrote:
...
> Whatever i like to hope that humans wont kill us all. It's nature that
> we've screwed with too much which might extract its inevitable revenge.
...
The worst-case scenario to which I alluded in an earlier post sees 
temperatures rising to a point at which evaporation exceeds 
precipitation, globally. Water vapour being a powerful greenhouse gas, 
that triggers a feedback effect. Eventually, all of the water is in the 
atmosphere. At that point, surface temperatures rise to something over 
200 degrees Celsius. There was something about atmospheric pressure more 
than 90 times what it is now as well.

Oceans don't evaporate overnight; it takes millennia. Humanity would go, 
slowly and miserably, extinct. It would take centuries.

Nobody really knows where the tipping point lies, but minds like Sagan 
and Hawking have warned that we shouldn't assume that it can't happen. 
In at least one talk, Hawking raised the possibility that the tipping 
point has already been passed; it's just that we're going to Hell so 
slowly at present that nobody's noticed.

-- 
David Boxall                    |  When a distinguished but elderly
                                |  scientist states that something is
http://david.boxall.id.au       |  possible, he is almost certainly
                                |  right. When he states that
                                |  something is impossible, he is
                                |  very probably wrong.
                                                  --Arthur C. Clarke