Tuscan-Emilian Apennines July Temperature Reconstruction using Fossil Midge assemblages covering the last 14,000 years Samartin, S.; Heiri, O.; Joos, F.; Renssen, H.; Franke, J.; Brönnimann, S.; Tinner, W. Samartin, S. Heiri, O. Joos, F. Renssen, H. Franke, J. Brönnimann, S. Tinner, W. Air Temperature Reconstruction earth science/paleoclimate/climate reconstructions|insect|paleolimnology (depth,null,null,centimeter,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (depth,null,null,centimeter,null,climate reconstructions|insect|paleolimnology,null,null,N,depth from sediment-water interface) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,smoothed,null,N,Loess smoother; calibration data set: Heiri et al. 2011 doi:10.1016/j.quascirev.2011.09.006) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,one standard error,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,null,N,Sample-specific estimated standard error of prediction; calibration data set: Heiri et al. 2011 doi:10.1016/j.quascirev.2011.09.006) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (age,null,null,calendar year before present,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,null,N,calibration data set: Heiri et al. 2011 doi:10.1016/j.quascirev.2011.09.006) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,anomalized,null,N,relative to mean 1850 AD to 2000 cal. yr BP; calibration data set: Heiri et al. 2011 doi:10.1016/j.quascirev.2011.09.006) earth science/paleoclimate/reconstructions (Lago Gemini Inferiore>LATITUDE 44.39>LONGITUDE 10.05) (Lago Verdarolo>LATITUDE 44.36>LONGITUDE 10.12) Understanding past climate trends is key for reliable projections of global warming and associated risks and hazards. Uncomfortably large discrepancies between vegetation-based summer temperature reconstructions, mainly based on pollen, and climate model results have been reported for the current interglacial, the Holocene. For the Mediterranean region these reconstructions indicate cooler-than-present mid-Holocene summers, in contrast with expectations based on climate models and long-term changes in summer insolation. We present new quantitative and replicated Holocene summer temperature reconstructions based on fossil chironomid midges from the northern central Mediterranean region. The Holocene thermal maximum is reconstructed 9000-5000 years ago and estimated to have been 1-2 °C warmer in mean July temperature than the recent preindustrial period, consistent with glacier and marine records, and with transient climate model runs. This combined evidence implies that widely used pollen-based summer temperature reconstructions in the Mediterranean area are significantly biased by precipitation or other forcings such as early land use. Our interpretation can resolve the previous discrepancy between climate models and quantitative palaeotemperature records for millennial-scale Holocene summer temperature trends in the Mediterranean region. It also suggests that pollen-based evidence for cool mid-Holocene summers in other semi-arid to arid regions of the Northern hemisphere may have to be re-considered, with potential implications for global-scale reconstructions. STUDY NOTES: Chironomid-inferred mean July air temperatures reconstructed for the study site based on the calibration data and transfer function described in Heiri et al. 2011 doi:10.1016/j.quascirev.2011.09.006. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Samartin, S. Investigator : Heiri, O. Investigator : Joos, F. Investigator : Renssen, H. Investigator : Franke, J. Investigator : Brönnimann, S. Investigator : Tinner, W. 2017-01-12 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/21030 https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/europe/samartin2017/samartin2017-gemini.txt https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/europe/samartin2017/samartin2017-verdarolo.txt https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/europe/samartin2017/samartin2017-gemini.txt https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/europe/samartin2017/samartin2017-verdarolo.txt English https://www.ncdc.noaa.gov/paleo/study/21030 https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/europe/samartin2017/samartin2017-gemini.txt https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/europe/samartin2017/samartin2017-verdarolo.txt Samartin, Stéphanie, Oliver Heiri, Fortunat Joos, Hans Renssen, Jörg Franke, Stefan Brönnimann, and Willy Tinner2017Warm Mediterranean mid-Holocene summers inferred from fossil midge assemblagesNature Geoscience10.1038/NGEO2891 START YEAR: 14020 cal yr BP * END YEAR: -59 cal yr BP 10.05 44.36 10.12 44.39