Northern OscillationsNorthern Oscillations and the Great Climate Flip-Flop Great Climate Flip-Flop Northern OscillationsGreat Climate Flip-Flop Poorna Pal MS MBA Ph.D. Professor of Geology Glendale Community College

The Great Climate Flip-flop by WILLIAM H. CALVIN When 'climate change' is referred to in the press, it normally means greenhouse warming, which, it is predicted, will cause flooding, severe windstorms, and killer heat waves. But warming could also lead, paradoxically, to abrupt and drastic cooling — a catastrophe that could threaten the end of civilization.

Observed Sea Surface Temperatures (°C) 7-day average centered on Jan 10, 2001 Observed Sea Surface Temperature Anomalies (°C)

1Gulf Stream 2N. Atlantic Drift 3Labrador current 4W. Greenland Drift 5E. Greenland Drift 6Canary current 7N. Equatorial current 8N. Equatorial CC 9S. Equatorial current 10S. Equatorial CC 11Equatorial CC 12Kuroshio current 13N. Pacific Drift 14Alaska current 15Oyashio current 16California current 17Peru (Humbolt) current 18Brazil current 19Falkland current 20Benguela current 21Agulhas current 22West Wind Druft 23W.Australian current 24E. Australian current 23 24

Strong Negative Phase reflects subnormal heights and pressures at high latitudes, ab- normal heights and pressures over central North Atlantic, eastern US and western Europe;reflects subnormal heights and pressures at high latitudes, ab- normal heights and pressures over central North Atlantic, eastern US and western Europe; tends to be associated withtends to be associated withColder eastern US, western Europe Warmer Greenland, southern Europe Drier northern Europe, ScandinaviaWetter southern and central Europe Strong Positive Phase reflects abnormal heights and pressures at high latitudes, sub- normal heights and pressures over central North Atlantic, eastern US and western Europe;reflects abnormal heights and pressures at high latitudes, sub- normal heights and pressures over central North Atlantic, eastern US and western Europe; tends to be associated withtends to be associated withWarmer eastern US, western Europe Colder Greenland, southern Europe Wetter northern Europe, ScandinaviaDrier southern and central Europe

Jan-50Jan-60Jan-70Jan-80Jan-90Jan-00 Northern Oscillation Index Monthly Data Annually Averaged Data

Wave Number Relative Energy 85.3 years 9.5 years 2.7 years 2.5 years 5.7 years Lag (Months) Autocorrelation 96 months The Spectral (below) and Correlogram (alongside) Analyses of Monthly NOI Data since 1950

The Global Conveyor Belt Broecker, W.S. "The great ocean conveyor," Oceanography,4:79-89 (1991).

Atlantic meridional section at 25°W: Temperature

Atlantic meridional section at 25°W: Salinity

Atlantic meridional section at 25°W: Density

Stream functions of meridional ocean transport in the Atlantic for the present climate (left).

Stream functions of meridional ocean transport in the Atlantic for the last glacial maximum (right),

A.D. Mean Annual Temperature (°C) Northern Hemisphere Southern Hemisphere Global average Global mean temperature since 1866

,0001,2001,4001,6001,8002,000 AD Southern Hemisphere Northern Hemisphere Jones, P.D., Briffa, K.R., Barnett, T.P. and Tett, S.F.B. High-resolution palaeoclimatic records for the last millennium: interpretation, integration and comparison with General Circulation Model control-run temperatures THE HOLOCENE, 8: (1998) δT (° C) Through most of the last millennium, though, Southern Hemisphere has been generally warmer than the Northern Hemisphere

Annual Change Frequency Mean Annual Change Standard Deviation =1.48  = % Probability that annual change will be Annual temperature changes in the past millennium

Z-Scale Cumulative Frequency Observed Data The Normal Curve The tail probabilities exceed those predicted by the Normal distribution model The past millennium

,000100,000150,000200,000250,000 δ 18 O Years BP GRIP δT (°C) Vostok ,00030,00040,00050,000 δ 18 O GRIP: Blunier et al. NATURE, 394: (1998) Younger Dryas J. Jouzel, C. Lorius, J.R. Petit, N.I. Barkov & V.M. Kotlyakov (1994): “Vostok isotopic temperature record” in TRENDS: A COMPEDIUM OF DATA ON GLOBAL CHANGE [ORNL/CDIAC-65. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn., U.S.A.] S.J. Johnson, D. Dahl-Jensen, W. Dansgaard & N.S. Gundestrup (1995): “Greenland palaeotemperatures derived from GRIP borehole temperature and ice core isotope profiles” TELLUS, 47B:

Annualized temperature changes as seen in the Ka BP GRIP record Annualized Change Frequency Mean Annualized Change Standard Deviation =-4.30  = % Probability that annual change will be 0.02

Z-Scale Cumulative Frequency The Normal Curve Observed Data The tail probabilities exceed those predicted by the Normal distribution model Ka BP GRIP Data

The past millennium has been about as stable, temperature-wise, as the past Ka BP interval that included the Younger Dryas Ice Age.

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