David B. Benson wrote:
> Decadal GISP2 Variability during the Holocene
>
> I take the Holocene as beginning 9900 ypb (years
> before present), the draining of Galcial Lake
> Aggassiz, to 1850 CE, 100 ypb.
[cut]
> Based on a statement that the 8.2 kybp event depressed
> temperatures in the tropics about 3 K, it appears that
> 1 K GISP = 1.5 K HadCRUT3v
> might be about right.
>
> I welcome discussion, especially regarding the
> conversion factor.
I thought that the most recent notions about the cause of the 8200
year BP event was flooding from glacial melt water causing a shutdown
of the THC. Volcanic effects can be tricky, since it's the sulfate
emissions into the stratosphere which have the most long term impact,
not the larger dust particles. The dust is removed from the lower
atmosphere rather rapidly by rain and gravity, while the sulfate
declines over a number of years. An eruption with a large Dust Veil
Index may not have as large an impact as a smaller, sulfur rich
eruption.
How do you discount the evidence for a weakening or shutdown of the
THC?
Christopher R. W. Ellison, Mark R. Chapman, and Ian R. Hall, Surface
and Deep Ocean Interactions During the Cold Climate Event 8200 Years
Ago, Science 30 June 2006: 1929-1932
Richard A. Kerr, Atlantic Mud Shows How Melting Ice Triggered an
Ancient Chill, Science 30 June 2006: 312, 1860
E. S.
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