Global warming could render “large fraction of the planet uninhabitable”
May 10th, 2010 by Jim JustA new paper in the Proceedings of the National Academy of Sciences (PNAS) concludes there is a “small” (order 5%) risk that global warming will render a large fraction of the planet uninhabitable – like, being outside for any length of time would result in death.
Stuart Staniford at Early Warning has conveniently posted a couple of maps from the paper (which would otherwise cost you $10 to get a peak at). First, today’s world.

Currently, the inland Amazon and northern India are pretty uncomfortable, with the eastern US, northern China, and much of Australia not far behind.
Right now, we are tracking above the worst case IPCC scenario (which, if you remember, does not include feedback loops such as the Arctic releasing methane). If we don’t do anything about climate change, we could get to about two doublings by the end of the century (over pre-industrial levels of 280ppm of CO2). With the caveat that there is a great deal of uncertainty regarding Earth’s climate sensitivity, what might that world look like ?

Most of the world’s major population centers will be uninhabitable outdoors – meaning people would drop dead – during heat waves.
Of course, this says little about the Earth’s capability to support agriculture under such conditions. People would drop dead of starvation long before they would drop dead of heat stroke.



