Last Glacial Maximum Temperature Reconstructions and Climate Sensitivity Schmittner, A.; Urban, N.M.; Shakun, J.D.; Mahowald, N.; Clark, P.U.; Bartlein, P.J.; Mix, A.C.; Rosell-Melé, A. Schmittner, A. Urban, N.M. Shakun, J.D. Mahowald, N. Clark, P.U. Bartlein, P.J. Mix, A.C. Rosell-Melé, A. Air Temperature Reconstruction Last Glacial Maximum sensitivity earth science/paleoclimate/paleoclimatic modeling (surface air temperature,null,null,degree Celsius,null,paleoclimatic modeling,null,null,N,null) earth science/paleoclimate/paleoclimatic modeling (sea ice cover,null,null,square meter,null,paleoclimatic modeling,null,null,N,null) earth science/paleoclimate/paleoclimatic modeling (sea surface temperature,null,null,degree Celsius,null,paleoclimatic modeling,null,null,N,null) earth science/paleoclimate/model (Global>LATITUDE >LONGITUDE ) 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. STUDY NOTES: 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 NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Schmittner, A. Investigator : Urban, N.M. Investigator : Shakun, J.D. Investigator : Mahowald, N. Investigator : Clark, P.U. Investigator : Bartlein, P.J. Investigator : Mix, A.C. Investigator : Rosell-Melé, A. 2011-12-09 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/12280 https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/uvic/schmittner2011/ https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/uvic/schmittner2011/readme-schmittner2011.txt https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/uvic/schmittner2011/ https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/uvic/schmittner2011/readme-schmittner2011.txt English https://www.ncdc.noaa.gov/paleo/study/12280 https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/uvic/schmittner2011/ https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/uvic/schmittner2011/readme-schmittner2011.txt 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 START YEAR: 21000 cal yr BP * END YEAR: 18000 cal yr BP -180 -90 180 90