Northern Hemisphere 700 Year Temperature Reconstruction Hegerl, G.C.; Crowley, T.J.; Hyde, W.T.; Frame, D.J. Hegerl, G.C. Crowley, T.J. Hyde, W.T. Frame, D.J. Air Temperature Reconstruction sensitivity temperature earth science/paleoclimate/climate forcing (volcanic forcing,null,null,watt per square meter,null,climate forcing,anomalized,null,N,volc0-30N) earth science/paleoclimate/climate forcing (greenhouse gas forcing,null,null,watt per square meter,null,climate forcing,anomalized,null,N,null) earth science/paleoclimate/climate forcing (volcanic forcing,null,null,watt per square meter,null,climate forcing,anomalized,null,N,volc30-90N) earth science/paleoclimate/climate forcing (volcanic forcing,null,null,watt per square meter,null,climate forcing,anomalized,null,N,volc0-30S) earth science/paleoclimate/climate forcing (volcanic forcing,null,null,watt per square meter,null,climate forcing,anomalized,null,N,volc30-90S) earth science/paleoclimate/climate reconstructions (surface temperature,null,null,degree Celsius,annual,climate reconstructions,anomalized,null,N,null) earth science/paleoclimate/climate reconstructions (surface temperature,null,percentile,degree Celsius,annual,climate reconstructions,anomalized,null,N,2.5th percentile) earth science/paleoclimate/climate forcing (solar irradiance,null,null,watt per square meter,null,climate forcing,anomalized,null,N,null) earth science/paleoclimate/climate forcing (age,null,null,year Common Era,null,climate forcing,null,null,N,null) earth science/paleoclimate/climate forcing (anthropogenic aerosol forcing,null,null,watt per square meter,null,climate forcing,anomalized,null,N,tropospheric aerosols) earth science/paleoclimate/climate reconstructions (surface temperature,null,percentile,degree Celsius,annual,climate reconstructions,anomalized,null,N,97.5th percentile) earth science/paleoclimate/climate reconstructions (age,null,null,year Common Era,null,climate reconstructions,null,null,N,null) earth science/paleoclimate/reconstructions (Northern Hemisphere Extratropics>LATITUDE >LONGITUDE ) The magnitude and impact of future global warming depends on the sensitivity of the climate system to changes in greenhouse gas concentrations. The commonly accepted range for the equilibrium global mean temperature change in response to a doubling of the atmospheric carbon dioxide concentration, termed climate sensitivity, is 1.5-4.5 K. A number of observational studies, however, find a substantial probability of significantly higher sensitivities, yielding upper limits on climate sensitivity of 7.7 K to above 9 K. Here we demonstrate that such observational estimates of climate sensitivity can be tightened if reconstructions of Northern Hemisphere temperature over the past several centuries are considered. We use large-ensemble energy balance modelling and simulate the temperature response to past solar, volcanic and greenhouse gas forcing to determine which climate sensitivities yield simulations that are in agreement with proxy reconstructions. After accounting for the uncertainty in reconstructions and estimates of past external forcing, we find an independent estimate of climate sensitivity that is very similar to those from instrumental data. If the latter are combined with the result from all proxy reconstructions, then the 5-95 per cent range shrinks to 1.5-6.2 K, thus substantially reducing the probability of very high climate sensitivity. STUDY NOTES: 30-90°N annual mean temperature reconstruction (CH-blend), used with large-ensemble energy balance modelling to simulate the temperature response to past solar, volcanic and greenhouse gas forcing, in order to determine which climate sensitivities yield simulations that are in agreement with proxy reconstructions. The data include the CH-blend reconstruction and 2.5% and 97.5% uncertainty ranges. The uncertainty ranges reflect both uncertainty in the amplitude of the reconstruction, and sampling uncertainty combined. Forcing inputs also included in file hegerl2006forcing.txt Supplementary Table 1 archived here, and its heading, were replaced on 5 February 2007. This is a corrected version of the previous Table S1, in which only the scaling uncertainty was included; in the corrected Table S1, scaling and sampling uncertainties are also included. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Hegerl, G.C. Investigator : Crowley, T.J. Investigator : Hyde, W.T. Investigator : Frame, D.J. 2013-07-11 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/14749 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hegerl2006/hegerl2006forcing.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hegerl2006/hegerl2006nh-temp.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hegerl2006/hegerl2006forcing.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hegerl2006/hegerl2006nh-temp.txt English https://www.ncdc.noaa.gov/paleo/study/14749 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hegerl2006/hegerl2006forcing.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hegerl2006/hegerl2006nh-temp.txt Gabriele C. Hegerl, Thomas J. Crowley, William T. Hyde, and David J. Frame. 2006. Climate sensitivity constrained by temperature reconstructions over the past seven centuries. Nature, Vol. 440, No. 7087, pp. 1029-1032, 20 April 2006. DOI: 10.1038/nature04679 START YEAR: 1000 AD * END YEAR: 2001 AD -180 30 180 90