Interesting that you bring up the Sahara. Freeman Dyson, who says that it might be possible that GW is happening, though caused by what would be very difficult to say, claims that if there is GW one of the results most probably will be a wet Sahara. At all times in the past when the global average temperature was higher than it is in recent millenia, the Sahara was wet.
So what’s a wet Sahara worth? According to Dyson, it’s worth a lot, a whole hell of a lot. It might be worth having all the other “problems” that will come with a warmer climate, if there is a warmer climate, caused by as-yet-undetermined causes.
This is not a big issue with me (the whole wet Sahara thing) since I don’t believe there is any warming, but rather actual cooling. However, since you mentioned the Sahara, and since Dyson is such a clever fellow, I thought I’d throw this in.
Too bad most of the people in the Sahara aren’t very conducive to taking advantage of the benefits of a wet Sahara.
SAHARA DESERT was once Ocean