Hasbeen,

Interestng post.

My understanding is that the population of Central and South America numbered in the millions prior to the arrival of the Europeans. In essence Europeans wiped out entire civilisations.

I've been following the work of Michael Palace with interest. He's an archaeologist who uses satellite imaging. One of his projects is to estimate the pre-Columbian population of the Aamazon Basin.

See:

http://www.eos.unh.edu/Faculty/Palace

and

http://www.eos.unh.edu/newsl_0610/palace.shtml

Stephen, I understand the warming tend, but the claim is that there was a sudden spike downwards in temperature due to the reforestation. that seems unlikely, given the scale of DEforestation since has not resulted in a similar upward spike.

Antispetic wrote:

>>...given the scale of DEforestation since has not resulted in a similar upward spike.>>

That's fair comment.

What I do find interesting though is the finding, from, isotope studies of core / forest sponge samples, that there was an apparent uptick in photosynthetic activity during the period under consideration.

BTW was there really a little ice age? If so was it a local European phenomenon or was it really a planetary wide cooling? I think there's reason to be sceptical.

See:

http://www.realclimate.org/index.php/archives/2004/11/little-ice-age-lia/

Quote:

>>A number of myths or exaggerations can still be found in the literature with regard to the details of this climate period [see Jones and Mann, 2004]. These include the citation of frost fairs on the River Thames as evidence of extreme cold conditions in England. Thames freeze-overs (and sometimes frost fairs) only occurred 22 times between 1408 and 1814 [Lamb, 1977] when the old London Bridge constricted flow through its multiple piers and restricted the tide with a weir. After the Bridge was replaced in the 1830s the tide came further upstream and freezes no longer occurred, despite a number of exceptionally cold winters. Winter 1962/3, for example, was the third coldest winter recorded in instrumental records extending back to 1659, yet the river only froze upstream of the present tidal limit.>>

The same uncertainty applies to the "mediaeval warm period" or MWP.

http://www.realclimate.org/index.php/archives/2004/11/medieval-warm-period-mwp/

My own feeling is that the inherent errors involved in trying to reconstruct past temperatures are too great for us to make these fine distinctions

Thanks for the interesting links, Steven. I don't normally pay much attention to climate science discussions, mostly because they seem to be, like Macbeth foretold "full of sound and fury, signifying nothing". To use your words, "the inherent errors involved in trying to reconstruct past temperatures are too great".

I really only responded because the claim of reforestation as the principal driver of the LIA seemed unreasonable on the face of it.

That's not to say that it wasn't correlated, but as we know, correlation does not imply causation.