Arctic Environmental Change of the Last Four Centuries:  readme file
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			World Data Center-A for Paleoclimatology
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NOTE: PLEASE CITE CONTRIBUTORS WHEN USING THIS DATA!!!!!

NAME OF DATA SET:  Arctic Environmental Change of the Last Four Centuries

CONTRIBUTORS:  J. Overpeck, K. Hughen, D. Hardy, R. Bradley, R. Case, M. Douglas, 
B. Finney, K. Gajewski, G. Jacoby, A. Jennings, S. Lamoureux, A. Lasca, G. MacDonald, 
J. Moore, M. Retelle, S. Smith, A. Wolfe, & G. Zielinski.


LAST UPDATE:  3/98 (original receipt by WDC-A Paleo)

IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 1997-033

SUGGESTED DATA CITATION:
Overpeck, et al, Arctic Environmental Change of the Last Four Centuries, 
IGBP PAGES/World Data Center-A for Paleoclimatology 
Data Contribution Series #1997-033, 
NOAA/NGDC Paleoclimatology Program, Boulder, CO.

GEOGRAPHIC REGION: Arctic Basin
ORIGINAL REFERENCE:  Arctic Environmental Change of the Last Four Centuries, 
J. Overpeck, K. Hughen, D. Hardy, R. Bradley, R. Case, M. Douglas, B. Finney, 
K. Gajewski, G. Jacoby, A. Jennings, S. Lamoureux, A. Lasca, G. MacDonald, 
J. Moore, M. Retelle, S. Smith, A. Wolfe, & G. Zielinski. 
Science, v. 278, n. 5341 p. 1251-1256, 1997.


PERIOD OF RECORD: 1600 AD-present.
LIST OF FILES:  Overpeck1997.readme (this file), arctemp.txt, pale5yr.txt,
table1.txt, ellesmere.txt, solar.txt, volcan.txt.

DESCRIPTION:  
For graphics and discussion of the data from this paper, see the web site
http://www.ngdc.noaa.gov/paleo/sciencepub/front.htm.

Site locations are detailed in file table1.txt.

Abstract 
A compilation of paleoclimate records from lake sediments, trees, glaciers, 
and marine sediments provides a view of circum-Arctic environmental variability 
over the last 400 years. From 1840 to the mid-20th century, the Arctic warmed 
to the highest levels in four centuries. This warming ended the Little Ice Age in the 
Arctic and has caused dramatic retreats of glaciers, melting of permafrost and sea-ice, 
and alteration of terrestrial and lake ecosystems. Although significant warming, 
particularly after 1920, was likely due to increases in atmospheric trace-gases, 
the initiation of the warming in the mid-19th century suggests that increased 
solar irradiance, decreased volcanic activity, and feedbacks internal to the 
climate system played roles.