Re: Association of Wildfires with Hypothetical Younger Dryas Impact Disputed

[Jeff Hecht <jeff@jeffhecht.com>]

Thanks for posting that. I had spotted the PNAS paper but not the Netherlands 
Journal of Geosciences paper.

I have a piece in the latest New Scientist commenting on the appeal and the 
problems of the Younger Dryas impact hypothesis. 
<http://www.newscientist.com/article/mg20126947.000-beware-earthshattering-headlines.html>

Basically the hypothesis doesn't fit well with the observed data. According to 
an impact specialist, the "nanodiamonds" cited as evidence for an impact in the 
1 January Science were nothing of the sort. There also are problems with the 
charcoal evidence and matching the event to the demise of the megafauna and the 
Younger Dryas. Another beautiful theory slain by a few ugly facts.

At 1:33 PM -0800 2/6/09, Paul wrote:
>Two papers, both of which dispute the occurrence of wildfires
>associated with a hypothetical impact event at the start of the
>Younger Dryas, have been recently published. They are:
>
>1. Marlon, J. R., P. J. Bartlein, M. K. Walsh, S. P. Harrison,
>K. J. Brown, M. E. Edwards, P. E. Higuera, M. J. Power, R. S.
>Anderson, C. Briles, A. Brunelle, C. Carcaillet, M. Daniels,
>F. S. Hu, M. Lavoie, C. Long, T. Minckley, P. J. H. Richard,
>A. C. Scott, D. S. Shafer, W. Tinner, C. E. Umbanhowar, Jr.,
>and C. Whitlock, 2009, Wildfire responses to abrupt climate
>change in North America. Proceedings for the National
>Academy of Science. Published online before print
>February 3, 2009, doi: 10.1073/pnas.0808212106
>
>Abstract at:
>
>http://www.pnas.org/content/early/2009/02/03/0808212106.abstract
>
>and 2. van der Hammen, T. and B. van Geel, 2008, Charcoal
>in soils of the Allerød-Younger Dryas transition were the
>result of natural fires and not necessarily the effect of an extra-
>terrestrial impact. Netherlands Journal of Geosciences (Geologie
>en Mijnbouw) vol. 87, no. 4, pp. 359-361.
>
>PDF file at:
>
>http://www.imep-cnrs.com/docu/charcoal.pdf
>http://www.njgonline.nl/publish/articles/000404/english.html
>
>A paper about the role of climatic change unrelated to
>extraterrestrial impacts in wildfire synchrony is:
>
>Kitzberger, T., P. M. Brown, E. K. Heyerdahl, T. W. Swetnam,
> and T. T. Veblen, 2007, Contingent Pacific-Atlantic Ocean
>influence on multicentury wildfire synchrony over western
>North America. Proceedings of the National Academy of
>Sciences of the United States of America. vol. 104 , no. 2.
>pp. 543-548.
>
>Abstract at:
>
>http://www.pnas.org/content/104/2/543.abstract
>
>Yours,
>
>Paul H.
>
>
>     

-- 
Jeff Hecht, science & technology writer
jeff@jeffhecht.com or jhecht@nasw.org
Boston Correspondent: New Scientist magazine
525 Auburn St., Auburndale, MA 02466 USA
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