Historically, warming leads to shrinking deserts, and cold earth eras were also the driest. Some researchers have found that the Sahara is shrinking as the Sahel spreads north (though the Sahel itself is threatened by desertification caused by bad agricultural practices).
A Guardian article on the impact of climate change on food security. This is worrying (albeit perhaps not a global catastrophic (or existential) risk). It has the potential to wipe out the gains made against extreme poverty in the last few decades.
Should we be so pessimistic? Climate change might be averted through government action or a technological fix; or the poorest might get rich enough to be protected from this insecurity; or we could see a second 'Green Revolution' with GM, etc. I've also seen some discussion that climate change could in fact increase food cultivation - in Russia and Canada for example.
How do people feel about this - optimistic or pessimistic?