Well, thanks Ray for explaining the oxygen isotope tool, and by extension I understand how carbon isotope measurements are used.
You then sent me off looking as sea level and temp; and that, leads of course. to the younger-dryas event. My “google scholar” search informs me that we don’t yet understand the younger-dryas, but that event seems to be the mark the initiation of the holocene period.
Younger-dryas seems like an aborted attempt to restart the glacial cycle, but lacked sufficient forcing function, so the switch did not flip (the oceans circulation (or bedrock) had an extra moment to equilibriate, robbing the glacial cycle of its momentum. In fact, a few hundered years earlier there seemed to be another abortive attempt.
After the younger-dryas event, CO2 levels no long follow the familiar relationship it had in past cycles.
Comparison with previous cycles (Vostok Ice Core) leads me to conclude the cycle is especially dependent on the CO2 forcing fuction right at the cycle midpoint.
Is there thought that successive glacial cycles have sequestered more and more carbon, eventually robbing the cycle of co2 forcing?
Yes, it was a very sad loss. Reading a Shackleton paper was always an inspiration for those of us training in the palaeoclimate field (though I’m still trying to get to grips with his 2000 Science paper!). His recent work on MIS 5e off the coast of Spain was particularly interesting and was of considerable assistance in my MSc research. Coming not long after the death of Gerard Bond, it was a real blow to the Quaternary Science community.
I collected a few of the obituaries in the British press and there is a tribute website over at the Godwin Lab:
Dr. Shackleton, a great man, who might, historically, be listed as one of the men who saved humanity.
But I am still a little hysterical.
I think we have a much bigger problem. I don’t think we can wait 100,000 years for the next orbital period and nature wants to recyle the biosphere through the glacial period. We are sitting in the hot house, and the carbon budget is not off by 6 gigatons per year, but more like 12 gigatons per year. At these temperature we likely have a much greater total flux than the biosphere can support indefinitely, much less a net flux.
We may need a solution on a much grander scale, like disenfecting the soils and killing of the soil microbes in a mass extinction. Otherwise, project the biosphere ahead at these temperature for 100,000 years, and it does not seem too pretty to me.
Comment by David B. Benson — 21 Feb 2006 @ 3:41 PM
It is sad news, and a significant loss. I met Sir Nick at a conference in Cambridge. At first I was afraid to talk to him because of his lofty reputation and title, but he was very kind. He will be missed.
Once out of nature I shall never take
My bodily form from any natural thing
But such a form as Grecian goldsmiths make
Of hammered gold, and gold enameling
To keep a drowsy emperor awake
Or set upon a golden bough to sing
To lords and ladies of Byzantium
Of what is past, or passing, or to come.
— W.B. Yeats