Global 784,000 Year Proxy and Model Temperature Reconstructions Friedrich, T.; Timmermann, A.; Tigchelaar, M.; Timm, O.; Ganopolski, A. Friedrich, T. Timmermann, A. Tigchelaar, M. Timm, O. Ganopolski, A. Air Temperature Reconstruction earth science/paleoclimate/paleoclimatic modeling (surface temperature,null,null,degree Celsius,null,paleoclimatic modeling,anomalized,null,N,global mean) earth science/paleoclimate/climate reconstructions|paleoceanography (age,null,null,calendar kiloyear before present,null,climate reconstructions|paleoceanography,null,null,N,null) earth science/paleoclimate/climate reconstructions|paleoceanography (surface temperature,null,null,degree Celsius,null,climate reconstructions|paleoceanography,anomalized,null,N,null) earth science/paleoclimate/reconstructions (Global>LATITUDE >LONGITUDE ) Global mean surface temperatures are rising in response to anthropogenic greenhouse gas emissions. The magnitude of this warming at equilibrium for a given radiative forcing - referred to as specific equilibrium climate sensitivity (S) - is still subject to uncertainties. We estimate global mean temperature variations and S using a 784,000-year-long field reconstruction of sea surface temperatures and a transient paleoclimate model simulation. Our results reveal that S is strongly dependent on the climate background state, with significantly larger values attained during warm phases. Using the Representative Concentration Pathway 8.5 for future greenhouse radiative forcing, we find that the range of paleo-based estimates of Earth's future warming by 2100 CE overlaps with the upper range of climate simulations conducted as part of the Coupled Model Intercomparison Project Phase 5 (CMIP5). Furthermore, we find that within the 21st century, global mean temperatures will very likely exceed maximum levels reconstructed for the last 784,000 years. On the basis of temperature data from eight glacial cycles, our results provide an independent validation of the magnitude of current CMIP5 warming projections. STUDY NOTES: Globally-averaged Surface Air Temperature anomaly reconstructed from proxy and model data for the last eight glacial cycles NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Friedrich, T. Investigator : Timmermann, A. Investigator : Tigchelaar, M. Investigator : Timm, O. Investigator : Ganopolski, A. 2017-01-03 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/21210 https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/friedrich2016/friedrich2016temp.txt https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/friedrich2016/friedrich2016temp.txt English https://www.ncdc.noaa.gov/paleo/study/21210 https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/friedrich2016/friedrich2016temp.txt Tobias Friedrich, Axel Timmermann, Michelle Tigchelaar, Oliver Elison Timm, Andrey Ganopolski2016Nonlinear climate sensitivity and its implications for future greenhouse warmingScience Advancese150192321110.1126/sciadv.1501923http://advances.sciencemag.org/content/2/11/e1501923 START YEAR: 783000 cal yr BP * END YEAR: 0 cal yr BP -180 -90 180 90