"Note that this is looking at long term past history, before the industrial age. If one considers the possible effects of anthropogenic global warming on top of these long term trends.....".

It looks like my profession of archaeology has bright future prospects as rainfall amounts regress towards the long term mean. And we can see the effects of rainfall variation
on past human populations in the west, although many other factors come into play.

I'm still holding out for icebergs. After all, we have been importing Alaskan liquids for quite a while, and icebergs are less polluting than the Exxon Valdez. Need I say that developing the iceberg technology will be a titanic undertaking?