Ugo Bardi; Albert Bates; Toby Hemenway
See Joe's comment about subsistence in the Marshall Islands: http://cassandralegacy.blogspot.com/201 ... mment-form
The default assumption is that, if the rest of the world goes away, a lot of Marshall Islanders will simply starve. Most people are too scared to make the equivalent assumption that if fossil fuels go away, most people in the 'rest of the world' will, likewise, starve. (Incidentally, look up the diabetes rate for the Marshall Islanders.)
Albert, based on his experiences with agriculture, thinks that providing enough food can be done...just maybe not in isolated sandy islands in the middle of the ocean. Toby Hemenway thought that the population of Earth in a Horticultural society would settle somewhere between 500M and 2Billion. Something to be aware of, if you are reading Albert's forthcoming essays, is what sorts of residue from the current industrial system he is assuming continue to function. Does he think there will be PV electricity, for example? Without electricity, then the ability to store perishable food is severely hampered. Some people may have spring houses, but certainly not 8 billion.
A similar issue arises with bad weather. Australian Aborigines who found drought or grasshoppers or floods in one place just walked to some different place. But they were spread thinly on the land, and did not really have permanent settlements with Passivhaus standards of construction. The temperature here in North Carolina tonight will be zero degrees F. This will be the third year in a row when freezes have severely hampered my fig tree. While the scientists may debate the issue, it seems clear to me that the weather patterns have become much less reliable and consequently food production much less dependable. (This is exactly what the State Climatologist told us would happen at a Climate Change and Farming conference 4 years ago.)
One of the principal problems we have with food production is the compaction of the soil...due to decades and centuries of hard usage. To break up compaction, it is very helpful to have a powerful tractor with a sub-soiler plow. Albert Bates did this with one of the fields at The Farm, putting some bio-char underground as he broke up the plow pan. Will Albert's master plan use some of our remaining fossil fuels to ameliorate compaction? If not, then we need to realize that a lot of those fields in the Midwest will produce very little in a climate challenged and fossil fuel-less world.
Consequently, it is hard to make reliable predictions of exactly what the population might be in a post-petroleum world. These are just a few examples of the kinds of uncertainties we face.