You're joking right? The majority of agriculture in the western world is produced directly because of the Gulf Streams warming effect, look at any agricultural output maps and you'll see North American and European production is squarely centred around where the gulf stream contacts the continent and increases local temperatures. As the global temperature increases vast amounts of land will be moved into the range of arable crops, specifically the two largest countries in the world (Canada and Russia) have very low percentages of arable land due to the vast amount of taiga, as temperatures increase the arable land will increase exponentially. These two countries could easily feed the world at present production densities. [Edit: Canada currently has less than 5% arable land, and presently only uses ~0.6% of all land for agriculture. Russia has about 7% arable land, but only uses ~0.1%. The prairies account for ~80% of Canada's agriculture land, and these very prairies are expected to grow exponentially as temperatures increase]

Incidentally your claim that the Sahara is expanding is quite frankly laughable, when all current evidence has been showing it is presently shrinking due to increased rainfall. Expectations are that if this trend continues it will turn into the 'Green Sahara' of 12,000 years ago. This would turn the Sahara into the biggest pasture land in the entire world . . . that's if you believe the global warming models being used.

The worse case is dire.:

"We have the example of the Palaeocene-Eocene Thermal Maximum event 55 million years ago. About the same amount of CO2 was put into the atmosphere as we are putting in and temperatures rocketed by about 5 °C over about 20,000 years. The world became largely desert. The polar regions were tropical and most life on the planet had the time to move north and survive." http://www.newscientist.com/article/mg20126921.500-one-last-...

http://en.wikipedia.org/wiki/Palaeocene-Eocene_Thermal_Maxim...

It would be, if the warming were even. Remember - as we increase the energy of the system, the _average_ temperature increases, but so does the range it's in. Cold will be colder, hot will be hotter, rainy will be rainier and windy will be windier.

It's not all roses.

I don't disagree with any of the above, but there is a small problem.

During the state transfer, the climate might change fast (there is some evidence for that happening before), which will (over a few years' time) make farming ... well, problematic.

It might be good for the world/humanity, but it sucks to get caught in the middle.

I agree, the climate can potentially change fast (it could potentially change very slowly, we're guessing at a process we haven't been around for before) which is why the burden will be on governments to monitor changes in arable land and provide incentives for farmers to grow crops in the areas opening up rather than waiting for our existing farmland to become useless.

With proper care and planning we should be able to ride out even the fastest change of climate that nature can throw at us, however I started this sentence 'with proper care' which is certainly not a synonym for the government handling of industry.