Last Glacial Maximum Temperature Reconstructions and Climate Sensitivity
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               World Data Center for Paleoclimatology, Boulder 
                                  and 
                     NOAA Paleoclimatology Program 
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NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! 


NAME OF DATA SET: 
Last Glacial Maximum Temperature Reconstructions and Climate Sensitivity 
LAST UPDATE: 12/2011 (Original receipt by WDC Paleo) 
CONTRIBUTORS: Schmittner, A., N.M. Urban, J.D. Shakun, N.M. Mahowald, 
P.U. Clark, P.J. Bartlein, A.C. Mix, and A. Rosell-Melé
IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2011-146 


WDC PALEO CONTRIBUTION SERIES CITATION: 
Schmittner, A., et al. 2011. 
Last Glacial Maximum Temperature Reconstructions and Climate Sensitivity. 
IGBP PAGES/World Data Center for Paleoclimatology 
Data Contribution Series # 2011-146. 
NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. 


ORIGINAL REFERENCE: 
Schmittner, A., N.M. Urban, J.D. Shakun, N.M. Mahowald, P.U. Clark,
P.J. Bartlein, A.C. Mix, and A. Rosell-Melé. 2011. 
Climate Sensitivity Estimated from Temperature Reconstructions 
of the Last Glacial Maximum. 
Science, Vol. 334, No. 6061, pp. 1385-1388, 9 December 2011. 
DOI: 10.1126/science.1203513 
Published Online November 24 2011

ABSTRACT: 
Assessing impacts of future anthropogenic carbon emissions 
is currently impeded by uncertainties in our knowledge of 
equilibrium climate sensitivity to atmospheric carbon dioxide 
doubling. Previous studies suggest 3 K as best estimate, 
2-4.5 K as the 66% probability range, and non-zero probabilities 
for much higher values, the latter implying a small but significant
chance of high-impact climate changes that would be difficult 
to avoid. Here, combining extensive sea and land surface temperature 
reconstructions from the Last Glacial Maximum with climate model 
simulations, we estimate a lower median (2.3 K) and reduced 
uncertainty (1.7-2.6 K 66% probability). Assuming paleoclimatic
constraints apply to the future as predicted by our model,
these results imply lower probability of imminent extreme
climatic change than previously thought. 



ADDITIONAL REFERENCES: 
Bartlein, P.J.,  S.P. Harrison, S. Brewer,  S. Connor, B.A.S. Davis, 
K. Gajewski, J. Guiot, T.I. Harrison-Prentice, A. Henderson, 
O. Peyron, I.C. Prentice,  M. Scholze,  H. Seppa,  B. Shuman,  
S. Sugita, R.S. Thompson,  A.E. Viau, J. Williams, and H. Wu.  2010. 
Pollen-based continental climate reconstructions at 6 and 21 ka: 
a global synthesis. 
Climate Dynamics, Vol. 37, No. 3-4, pp. 775-802. 
DOI: 10.1007/s00382-010-0904-1 

MARGO Project Members. 2009. 
Constraints on the magnitude and patterns of ocean cooling 
at the Last Glacial Maximum. 
Nature Geoscience, Vol. 2, pp. 127-132, February 2009. 
DOI: 10.1038/NGEO411 

Shakun, J.D., and Coauthors. 2012. 
Influence of CO2 and ocean circulation on global climate 
during the last deglaciation.
Nature, in review. 



GEOGRAPHIC REGION: Global
PERIOD OF RECORD: Last Glacial Maximum, ~18 KYrBP 

FUNDING SOURCES: 
US National Science Foundation Paleoclimate Program, 
project PALEOVAR (06023950-ATM).  



DESCRIPTION: 
Data for Schmittner et al. 2011 
"Climate Sensitivity Estimated From Temperature Reconstructions 
of the Last Glacial Maximum" Science 334:1385. 
Data archived at NOAA/WDC for Paleoclimatology: 
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/gcmoutput/uvic/schmittner2011/ 

Bartlein et al. 2010 data set available at: 
http://www.springerlink.com/content/2762k2451307l623/382_2010_Article_904_ESM.html 
or 
http://www.ncdc.noaa.gov/paleo/pubs/bartlein2010/bartlein2010.html 

MARGO Project data are available at: 
http://www.ncdc.noaa.gov/paleo/pubs/margo2009/margo2009.html 
and in the netCDF file margo09.nc 

Shakun et al. LGM temperature anomalies are available as a combined 
Excel file:
LGM_deltaT_synthesis_Shakun_etal_2011.xlsx 
or as three separate netcdf files containing updated MARGO grid points: 
dt_updated_MARGO.nc
other ocean grid points: 
dt_other_ocean.nc 
and land grid points on a 2x2 grid: 
dt_other_land_2x2.nc 
 
Note that the updates MARGO grid points should replace the corresponding 
data in the original MARGO dataset. 

A Table with references is also provided: 
Shakun_table.pdf 

The results from the UVic model simulations from the pre-industrial 
control and LGM simulations are in the file: 
sat_sst_aice.tar.gz

The probability density functions PDFs (Figure 3) are in file: 
ECS_pdfs.txt 
and the random samples from the Markov chains from which the pdfs 
were derived are in the file: 
ECS_chains.txt.gz