early ag influencing glaciation/extending the Holocene?
Mo and I watched the BBC's How the Earth Changed History, a set of 2 DVDs with 5 "chapters". Professor Iain Stewart walks us through a discussion of how water (access to fresh), deep earth (access to minerals along plate boundaries), wind (moving soil and weather), fire (energy resources), and humans (natch) have each constrained and contributed to how and where we have developed our bits of civilization.
Very pretty, informative, a little advance/broad for M (not that surprising). And he loved it. He said it was his favorite movie.* (he's quite fond of things like Wired Science.)
Then, in the human bit, Stewart referenced the idea that early agriculture (~7000 years ago) had affected climate, by extending this particular interglacial period via increased CO2 and CH4, the latter via rice paddies and somewhat 2000 years later than the grain farming. He based this on Vostok ice core data for those to greenhouse gases and anthropological/archeological history/evidence for the timing of events.
OK, so I should have heard of that, shouldn't I? Anyway, I turned to the web, to find out more. Aside from an extremely disappointing inability to access full-text articles in peer-reviewed journals (SIGH), I found out this:
William Ruddiman proposed this idea in 2002 or so (BBC covered this) in the journal Climactic Change. (but I can't get the full-text PDF, sadly) He presented it in Scientific American about 3 years later (first two paragraphs in SA), and later that same year, presented a response to some critiques on RealClimate.org. He's plugging along with this hypothesis still, now developing it into books (one recently out vis Princeton).
He's also said a lot more. For scientific paper abstracts (and links to purchaseable PDFs), I found ScienceDirect and Scirus useful.
Aside: Ruddiman points to possible ocean temperature warming... in 1970, based on plankton evidence. (Just the abstract here)
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* I don't know if this is still true. R happened to have come inside finally from whacking at the great nasty ice dams on our modern-construction roof (which therefore shouldn't get them, and does), just in time to catch this bit. So R (a "climate skeptic") said they (BBC/Stewart/producers) of lying and had an agenda. That clearly bothered Mo, who defended the series so far (!! At 6! Go M). I think I fell down here a little bit, as I have nearly utterly lost my appetite for debate--at least in person, if not in text (which is calmer and friendlier)--I only said I hadn't heard of this idea and that the rest of the series had been very good so far. Well... then I went and found out the above, which I summarized to R. He dismissed it, which I had expected, but as I had expected that and didn't debate it, this didn't bug me much. Perhaps unfortunately, M had fallen asleep by the time I did all that. Sigh.
Very pretty, informative, a little advance/broad for M (not that surprising). And he loved it. He said it was his favorite movie.* (he's quite fond of things like Wired Science.)
Then, in the human bit, Stewart referenced the idea that early agriculture (~7000 years ago) had affected climate, by extending this particular interglacial period via increased CO2 and CH4, the latter via rice paddies and somewhat 2000 years later than the grain farming. He based this on Vostok ice core data for those to greenhouse gases and anthropological/archeological history/evidence for the timing of events.
OK, so I should have heard of that, shouldn't I? Anyway, I turned to the web, to find out more. Aside from an extremely disappointing inability to access full-text articles in peer-reviewed journals (SIGH), I found out this:
William Ruddiman proposed this idea in 2002 or so (BBC covered this) in the journal Climactic Change. (but I can't get the full-text PDF, sadly) He presented it in Scientific American about 3 years later (first two paragraphs in SA), and later that same year, presented a response to some critiques on RealClimate.org. He's plugging along with this hypothesis still, now developing it into books (one recently out vis Princeton).
He's also said a lot more. For scientific paper abstracts (and links to purchaseable PDFs), I found ScienceDirect and Scirus useful.
Aside: Ruddiman points to possible ocean temperature warming... in 1970, based on plankton evidence. (Just the abstract here)
-------------------------------------------------
* I don't know if this is still true. R happened to have come inside finally from whacking at the great nasty ice dams on our modern-construction roof (which therefore shouldn't get them, and does), just in time to catch this bit. So R (a "climate skeptic") said they (BBC/Stewart/producers) of lying and had an agenda. That clearly bothered Mo, who defended the series so far (!! At 6! Go M). I think I fell down here a little bit, as I have nearly utterly lost my appetite for debate--at least in person, if not in text (which is calmer and friendlier)--I only said I hadn't heard of this idea and that the rest of the series had been very good so far. Well... then I went and found out the above, which I summarized to R. He dismissed it, which I had expected, but as I had expected that and didn't debate it, this didn't bug me much. Perhaps unfortunately, M had fallen asleep by the time I did all that. Sigh.