Northern Hemisphere hydroclimatic variability over the past twelve centuries Ljungqvist, F.C.; Krusic, P.J.; Sundqvist, H.; Zorita, E.; Brattström; Frank, D.C. Ljungqvist, F.C. Krusic, P.J. Sundqvist, H. Zorita, E. Brattström Frank, D.C. Other Hydroclimate Reconstruction Precipitation Reconstruction drought earth science/paleoclimate/climate reconstructions (longitude,null,null,degree east,null,climate reconstructions,null,null,N,null) earth science/paleoclimate/climate reconstructions (latitude,null,null,degree north,null,climate reconstructions,null,null,N,null) earth science/paleoclimate/climate reconstructions (age,null,null,year Common Era,null,climate reconstructions,null,null,N,null) earth science/paleoclimate/climate reconstructions (moisture index,multiple proxies,null,standard deviation unit,null,climate reconstructions,anomalized,null,N,null) earth science/paleoclimate/reconstructions (Northern Hemisphere>LATITUDE >LONGITUDE ) Accurate modelling and prediction of the local to continental-scale hydroclimate response to global warming is essential given the strong impact of hydroclimate on ecosystem functioning, crop yields, water resources, and economic security. However, uncertainty in hydroclimate projections remains large, in part due to the short length of instrumental measurements available with which to assess climate models. Here we present a spatial reconstruction of hydroclimate variability over the past twelve centuries across the Northern Hemisphere derived from a network of 196 at least millennium-long proxy records. We use this reconstruction to place recent hydrological changes and future precipitation scenarios in a long-term context of spatially resolved and temporally persistent hydroclimate patterns. We find a larger percentage of land area with relatively wetter conditions in the ninth to eleventh and the twentieth centuries, whereas drier conditions are more widespread between the twelfth and nineteenth centuries. Our reconstruction reveals that prominent seesaw patterns of alternating moisture regimes observed in instrumental data across the Mediterranean, western USA, and China have operated consistently over the past twelve centuries. Using an updated compilation of 128 temperature proxy records, we assess the relationship between the reconstructed centennial-scale Northern Hemisphere hydroclimate and temperature variability. Even though dry and wet conditions occurred over extensive areas under both warm and cold climate regimes, a statistically significant co-variability of hydroclimate and temperature is evident for particular regions. We compare the reconstructed hydroclimate anomalies with coupled atmosphere-ocean general circulation model simulations and find reasonable agreement during pre-industrial times. However, the intensification of the twentieth-century-mean hydroclimate anomalies in the simulations, as compared to previous centuries, is not supported by our new multi-proxy reconstruction. This finding suggests that much work remains before we can model hydroclimate variability accurately, and highlights the importance of using palaeoclimate data to place recent and predicted hydroclimate changes in a millennium-long context. STUDY NOTES: Comparison of gridded proxy reconstructed and climate model simulated hydroclimate and temperature variability across the Northern Hemisphere over the past twelve centuries. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Ljungqvist, F.C. Investigator : Krusic, P.J. Investigator : Sundqvist, H. Investigator : Zorita, E. Investigator : Brattström Investigator : Frank, D.C. 2016-04-07 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/19725 https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/hydroclimate/ljungqvist2016/ https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/hydroclimate/ljungqvist2016/readme-ljungqvist2016.txt https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/hydroclimate/ljungqvist2016/ https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/hydroclimate/ljungqvist2016/readme-ljungqvist2016.txt English https://www.ncdc.noaa.gov/paleo/study/19725 https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/hydroclimate/ljungqvist2016/ https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/hydroclimate/ljungqvist2016/readme-ljungqvist2016.txt Fredrik Charpentier Ljungqvist, Paul J. Krusic, Hanna S. Sundqvist, Eduardo Zorita, Gudrun Brattström, and David Frank2016Northern Hemisphere hydroclimatic variability over the past twelve centuriesNature532759794-9810.1038/nature17418http://www.nature.com/nature/journal/v532/n7597/full/nature17418.html START YEAR: 800 AD * END YEAR: 1999 AD -180 0 180 90