That is a good point, primarily because it would make staying outdoors dangerous in a number of additional places. For farming, I'm not sure it's that clear. M

That is a good point, primarily because it would make staying outdoors dangerous in a number of additional places. For farming, I'm not sure it's that clear. Many of these studies only consider the negative impacts. Obviously, many places would be left arid. But 7-8 temperature increase, along with increased rainfall (evaporated water has to come down somewhere), will massively increase the farming potential in places like Siberia, inland China and Canada. Increased rainfall can also potentially lead to absurd-sounding things such as rice farms in present-day Sahara. Finally, as you alluded to, aquatic farming has a huge potential. We are beyond the point where food production has to be local. As long as there is enough food globally, economically prosperous areas can buy the food they need. Also, keep in mind that when talking about a 4 degree increase, it is assumed to happen over several centuries. At the present rate of technologial development, it is impossible to say what impact it would have, as food production 200 years in the future is likely to be as different from today as it was 200 years in the past. Still, I absolutely think that at 4 degrees (at least if it happens within 200 years), the results would be a major catastrophy. Provided that we haven't been already wiped out (or domesticated) by runaway AI's or nuclear war, of course. (Both of which concern me more over the next 200 years)