CLIMATE MODEL SIMULATES GLOBAL COLD CLIMATE DURING LATE MAUNDER MINIMUM ( ) Hans von Storch, Fidel González-Ruoco, Ulrich Cubasch, Jürg Luterbacher, Eduardo Zorita, Beate Müller, Stephanie Legutke, and Ulrich Schlese IUGG Sapporo, JSP 01, 1./2. Juli : The decadal to interdecadal variability of the ocean and atmosphere.

Simulation with ECHO-G (ECHAM4/HOPE-G) for years (Columbus-run), and years (Erik run) forced with - variable solar output - Volcanic aerosol load - GHG concentrations

Late Maunder Minimum Cold winters and springs, Late Maunder Minimum Cold winters and springs, Analysis of Columbus run, only.

Baltic Sea ice winter index after Koslowski (1998) grey: Index, red: 5 year mean, blue:20 year mean

The Late Maunder Minimum (LMM) is the coldest phase of the so-called ‘Little Ice Age’ with marked climatic variability over wide parts of Europe. Temperature conditions in Switzerland according to Pfister‘s classification. From Luterbacher, vs Reconstruction from historical evidence, from Luterbacher et al.

vs Reconstruction from historical evidence, from Luterbacher et al. Late Maunder Minimum Model-based reconstuction

Simulated global temperature anomaly

Ice Cores From Greenland and Antarctica Stacked isotope record from five North-Greenland ice cores (Schwager, 2000) Stacked isotope record from three ice cores from Dronning Maud Land, Antarctica (Graf et al., in press ) Reconstruction of solar variability, deduced from 10 Be measurements (Crowley, 2000) Antarctica North Greenland

Corals off Madagaskar The empirically reconstructed 338 year record of variations in sea-surface temperatures as inferred from the annual mean  18 O -SST calibration equations using SST observations from different sources. (From Zinke)

 Galapagos (E-Pacific, 1 o S, 90 o W, Dunbar et al., 1994): 367 years of coral  18 O records from , with annual resolution. The intervals , and were found warmer than “normal”, whereas the intervals , (LMM) and cooler than on average.  18 O increases of about ‰ heavier during LMM than between and is indicative for a cooling of K.  New Caledonia (SW-Pacific, 22 o S, 166 o E, Quinn et al., 1998): 335 years of coral  18 O records from , with seasonal resolution. The records describe a brief interval of modest cooling in the late 17th century, with an annual mean SST about K cooler between than between and  Great Barrier Reef, Abraham Reef (SW-Pacific, 22 o S, 153 o E, Druffel and Griffin, 1993): 323 years of coral  18 O records from , with bi-annual resolution. More positive  18 O values (ca. 0.1‰) during the LMM, are consistent with lower SST’s of about 0.5K Zinke, pers. communication

deMenocal et al. (2000)

Simulated differences of ice coverage, in percent, during the LMM event and the long term mean Institut für Küstenforschung I f K

LMM NAO- and Cooling LMM NAO+ and Warming Irene Fischer-Bruns, pers. comm.

Conclusions AOGCM ECHO-G has been integrated with natural forcing (estimates) related to solar output and volcanic aerosols and anthropogenic GHG forcing over several hundred years (Columbus: 450 yrs, Erik the Red: 1000 yrs). Both simulations generate a globally cooler Northern winter Earth, , consistent with the concept of LIA. The cooling is considerably larger than described by Mann et al. The 100ß yrs Erik- simulation generates a medieval warm time during northern winter. Both simulations simulate a marked global (north of 20°S) cooling during the Late Maunder Minimum in Northern winter. (Also: Dalton Minimum). The extra cooling amounts to K. Model simulations consistent with a number of proxy data, in Europe, and across the globe (corals, ice cores). Model simulates a significant ice anomaly in the Labrador Sea and adjacent seas during the LMM. NAO not uniform during LMM.