CLIMATE MODEL SIMULATES GLOBAL COLD CLIMATE DURING

LATE MAUNDER MINIMUM (1675-1710)

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

- 500 years (Columbus-run), and - 1000 years (Erik run)

forced with

- variable solar output- Volcanic aerosol load- GHG concentrations

Late Maunder Minimum

Cold winters and springs, 1675-1710

Late Maunder Minimum

Cold winters and springs, 1675-1710

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, 2001

1675-1710vs. 1550-1800

Reconstruction from historical evidence, from Luterbacher et al.

1675-1710vs. 1550-1800

Reconstruction from historical evidence, from Luterbacher et al.

Late Maunder Minimum

Model-based reconstuction

Simulated global 1675-1710 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

10Be 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 1982-95 annual mean 18O -SST calibration equations using SST observations from different sources.

(From Zinke)

        Galapagos (E-Pacific, 1oS, 90oW, Dunbar et al., 1994):

367 years of coral 18O records from 1587-1953, with annual resolution. The intervals 1660-80, 1710-1800 and 1870-95 were found warmer than “normal”, whereas the intervals 1600-1660, 1680-1700 (LMM) and 1800-25 cooler than on average. 18O increases of about 0.1-0.15‰ heavier during LMM than between 1660-70 and 1705-50 is indicative for a cooling of 0.5-0.75K.

        New Caledonia (SW-Pacific, 22oS, 166oE, Quinn et al., 1998):

335 years of coral 18O records from 1657-1952, with seasonal resolution. The records describe a brief interval of modest cooling in the late 17th century, with an annual mean SST about 0.2-0.3K cooler between 1680-1740 than between 1660-80 and 1740-50

        Great Barrier Reef, Abraham Reef (SW-Pacific, 22oS, 153oE, Druffel and Griffin, 1993):

323 years of coral 18O records from 1635-1957, with bi-annual resolution. More positive 18O values (ca. 0.1‰) during the LMM, are consistent with lower SST’s of about 0.5K

Zin

ke, p

ers.

com

mun

icat

ion

deMenocal et al.

(2000)

Simulated differences of ice coverage, in percent, during the LMM event 1675-1710 and the long term mean 1550-1800.

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un

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I f K

LMM1 1671-1684 NAO- and Cooling

LMM2 1685-1708 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, 1400-1800, 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 0.2-0.5K.

• 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.