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Earth's Climatic History: The Last 2,000,000 Years
Throughout earth's geologic history, major ice ages have occurred over and over again, with ten of them affecting the planet in the past one million years (Erickson, 1990) and another ten in the million or so years before that (Whyte, 1995).  Indeed, they recur almost like clockwork at approximate 100,000-year intervals and persist for about 90,000 years, after which they are followed by approximate 10,000-year interglacials (Suarez and Held, 1976; Berger, 1978; Pollard, 1978; Schneider and Thompson, 1979; Williams et al., 1993). One million year temperature history Their periodicity is clearly discerned in the accompanying figure, which depicts the relative changes in mean global air temperature over several of the most recent cycles, as reported by the Intergovernmental Panel on Climate Change (IPCC) (Houghton et al., 1990).

The glacial epoch about which we know the most is the most recent one, which was at its peak only 18 to 20 thousand years ago.  At that time, approximately one-third of the earth's land area was covered by ice (West, 1977; Erickson, 1990; Williams et al., 1993).  In North America, the southern edge of the glacial ice extended all the way to the Ohio river valley and in some locations was over a mile (1.61 km) thick (Flint, 1971; Bowen, 1978; CLIMAP, 1981).  Other glaciers advanced around the world (Andrews, 1985; Barrett, 1991), extending through portions of England (West, 1977; Preece, 1995), Northern Europe (Coleman, 1969), Asia (Tung-sheng, 1991) and South America (Rabassa, 1983).  Mountain glaciers also formed and expanded in the tropical regions of New Guinea (Bowler et al., 1976), Hawaii (Porter, 1979), eastern Africa (Hamilton, 1982; Mahaney, 1990) and the Andes (Hastenrath, 1985; Fairbanks, 1989). At its peak extent, earth's glacial ice contained approximately 5 percent of the planet's water and reduced sea levels by as much as 120 meters (Fairbanks, 1989; Erickson, 1990; Williams et al., 1993; Andersen and Borns, 1994).

In North America, there were two major ice sheets: the Laurentide ice sheet and the Cordilleran ice sheet.  The Laurentide ice sheet was the larger of the two, covering five million square miles (16 x 106 km2) (Williams et al., 1993) and stretching from the Arctic down though eastern Canada to the northern half of the Midwestern United States (Erickson, 1990).  The Cordilleran ice sheet emanated from the Canadian Rockies and engulfed western Canada, Alaska and portions of the northwestern United States.  Large ice sheet growth was also seen in Europe, where the Fennoscandian ice sheet covered approximately 4 million square kilometers (Flint, 1957; Daly, 1973).  The weight of these massive ice sheets was so great that they actually depressed the earth's crust, in some cases by as much as 700-800 meters (Flint, 1971; West, 1977), creating gravity anomalies that are still detectable (Peltier, 1987).

In Antarctica, ice covered the continent and flowed to the sea, where it broke apart to form massive icebergs.  In fact, iceberg discharges in both hemispheres were so numerous during the peak of the last ice age (Bond et al., 1992; Broecker et al., 1992) that they covered half the area of the world's oceans (Erickson, 1990). As a result, sea surface temperatures in oceanic polar front regions dropped by as much as 6 to 10 °C, while the tropical oceans cooled from 2 to 8 °C (CLIMAP, 1981; Hughes, 1996; Beck et al., 1997; Webb et al., 1997).

The presence of the large ice sheets forced major changes in the general circulation of the atmosphere.  In North America, mean wind direction was primarily from the northwest (Wells, 1983), bringing cooler air further south.  Wind speeds also increased, by as much as 50-80% above current values in the North Atlantic and Southern oceans (Crowley and North, 1991), enhancing oceanic heat loss even more (Crowley and Parkinson, 1988).  In the Northern Hemisphere, the polar front moved 1200 km south of its current location to 34 °N (Delcourt, 1979; Delcourt and Delcourt, 1983).  As a result, annual temperatures in the mid-latitudes decreased by as much as 10 °C (Flint, 1971; Barry, 1983; Guiot et al., 1989), and by as much as 15-20 °C during the winter (Delcourt, 1979; Watts, 1980).

With few exceptions, the planet was much drier during the last ice age.  Ice cores from Greenland and Antarctica suggest that precipitation decreased about 50% in earth's polar regions during this period (Beer et al., 1985; Herron and Langway, 1985; Lorius et al., 1985).  Dust concentrations in the cores additionally suggest that most of earth's ice-free land was more arid than it is now (Petit et al., 1981; Hammer et al., 1985; Petit et al., 1990).  Other evidence points to the formation of large sand dunes in Central America and the sub-Sahara region of Africa, and to the contraction and fragmentation of the Amazon rainforest into a few small regions of high precipitation (Haffer, 1969; Prance, 1982).  Concurrently, the salinity of the Mediterranean Sea rose by 1-3%, while that of the Red Sea rose as much as 10% (Thunell et al., 1987; Thunell et al., 1988; Thunell and Williams, 1989).  In fact, the concentration of salt in the Red Sea was so high that it may have approached the upper tolerance limit of most planktonic organisms (Crowley and North, 1991).

Terrestrial plants throughout the world also suffered from lower atmospheric carbon dioxide concentrations during earth's last glacial episode, as the air's CO2 content fell to a level of approximately 180 ppm (Berner et al., 1980; Delmas et al., 1980; Barnola et al., 1987).  This drop in atmospheric CO2 was driven largely by the increased ability of colder water to hold more dissolved CO2 (Adey, 1991; Butler, 1991) and by the much larger growth rates of phytoplanktonic organisms in earth's open oceans (Pedersen, 1983; Muller et al., 1983; Lyle, 1988; Lyle et al., 1988), which removed more CO2 from the air (McElroy, 1983; Knox; 1984).  The enhanced growth rates of these tiny but multitudinous organisms were largely the result of the greater amounts of elemental iron (Martin and Fitzwater, 1988; Martin, 1990; Martin, 1992) contained in the augmented quantities of dust (DeAngelis et al., 1987; Gaudichet et al., 1988; Legrand et al., 1988) that were carried to them by the stronger winds of that period (Parkin and Shackleton, 1973; Sarnthein et al., 1981; Roger and Wilson, 1989).  Numerous studies have revealed that this low level of atmospheric CO2 concentration (180 ppm) greatly reduces vegetative productivity (Polley et al., 1992a, 1992b; Polley et al., 1993); and, had the CO2 concentration of the air dropped much lower, it is likely that several plant extinctions would have occurred, since many plants find it difficult to survive at CO2 concentrations on the order of 50 to 100 ppm (Idso, 1989; Salisbury and Ross, 1978).

Large and rapid shifts in climate have been detected in areas of the North Atlantic, Greenland, and in Antarctica from deep-sea sediment cores, ice cores, lake sediments, and pollen series that cover this period of time.  Most of these records provide climatic descriptions of the last glacial cycle, with some continuing on through the Emian interglacial over 120,000 years ago.

In Greenland, rapid warming - approximately 7°C in a few decades - was observed around 11,500 years ago (Dansgaard et al., 1989; Johnsen et al., 1992; Grootes et al., 1993). Alley et al. (1993) also report evidence of even more rapid shifts in precipitation patterns, and other authors have noted swift changes in atmospheric circulation (Taylor et al., 1993; Mayewski et al., 1993).  Sea surface temperature changes of around 5°C, associated with sudden changes in oceanic circulation, also occurred in a few decades in the Norwegian Sea (Lehman and Keigwin, 1992).  Similar warming following the latest deglaciation occurred in regions of the Southern Hemisphere, though the warming there was less abrupt (Suggate, 1990; Denton and Hendy, 1994; Salinger, 1994; Jouzel et al., 1995).

During the last glacial cycle, large warm-cold oscillations have been detected in central Greenland ice cores (Johnsen et al., 1992).  Rapid warmings of between 5 and 7 °C occurred in a few decades, followed by periods of slower cooling and then a rapid return to glacial conditions.  Around 20 such interstadial events occurred during the last glacial period and lasted between 500 and 2000 years (Dansgaard et al., 1993).  Similar rapid changes have been discovered in North Atlantic deep-sea cores, indicating massive iceberg discharges from the Northern Hemisphere ice sheets (Bond et al., 1993; Mayewski et al., 1994; Bond and Lotti, 1995); and they were followed by abrupt shifts to warmer sea surface temperatures.  Additional records from Western Europe, North America, and China (Grimm et al., 1993; Guiot et al., 1993; Porter and An Zhisheng, 1995) document rapid shifts in climate during the last glacial period; and such records have prompted the IPCC to categorize these interstadials as "at least hemispheric in their extent" (Houghton et al., 1996).

References
Adey, W.H. and Loveland, K.  1991.  Dynamic Aquaria: Building Living Ecosystems. Academic Press, New York, NY.

Alley, R.B., Meese, D.A., Shuman, C.A., Gow, A.J., Taylor, K.C., Grootes, P.M., White, J.C.W., Ram, M., Waddington, E.D., Mayewski, P.A. and Zielinski, G.A.  1993.  Abrupt increase in Greenland snow accumulation at the end of the Younger Dryas event.  Nature 362: 527-529.

Andersen, B.G. and Borns, H.W., Jr.  1994.  The Ice Age World.  Scandinavian University Press, Oslo, Norway.

Andrews, J.T. (Ed.).  1985.  Quaternary Environments: The Eastern Canadian Arctic, Baffin Bay and West Greenland.  Allen & Unwin Inc., Winchester, MA.

Barnola, J.M., Raynaud, D., Korotkevich, Y.S. and Lorius, C.  1987.  Vostok ice core provides 160,000-year record of atmospheric CO2Nature 329: 408-414.

Barrett, P.J.  1991.  Antarctica and global climatic change: A geological perspective.  In: Antarctica and Global Climate Change.  C.M. Harris and B. Stonehouse (Eds.).  Belhaven Press, London, UK.

Barry, R.G.  1983.  Late-Pleistocene Climatology.  In: Late-Quaternary Environments of the United States, The Late Pleistocene, v.1.  H.E. Wright and S.C. Porter (Eds.).  University of Minnesota Press, Minneapolis, MN, pp. 390-407.

Beck, J.W., Récy, J., Taylor, F., Edwards, R.L. and Cabioch, G.  1997.  Abrupt changes in early Holocene tropical sea surface temperature derived from coral records.  Nature 385: 705-707.

Beer, J., Andree, M., Oeschger, H., Stauffer, B., Balzer, R., Bonani, G., Stoller, Ch., Suter, M., Wölfli, W. and Finkel, R.C.  1985.  10BE variations in polar ice cores.  In: Greenland Ice Core: Geophysics, Geochemistry, and the Environment.  C.C. Langway, H. Oeschger, and W. Dansgaard (Eds.).  Geophysical Monograph 33.  American Geophysical Union, Washington, DC, pp. 66-70.

Berger, A.  1978.  Long-term variations of daily insolation and Quaternary climatic changes.  Journal of Atmospheric Sciences 35: 2362-2367.

Berner, W., Oeschger, H. and Stauffer, B.  1980.  Information on CO2 cycle from ice core studies.  Radiocarbon 22: 227-235.

Butler, J.N.  1991.  Carbon Dioxide Equilibria and Their Applications.  Lewis Publishers, Chelsa, MI.

Bond, G., Heinrich, H., Broecker, W., Labeyrie, L., McManus, J., Huon, S., Tantschie, R., Clasen, S., Simet, C., Tedesco, K., Klas, M., Bonam, G. and Ivy, S.  1992.  Evidence for massive discharges into the North Atlantic ocean during the last glacial period.  Nature 360: 245-249.

Bond, G.C., Broecker, W.S., Johnsen, S.J., Mc Manus, J., Labeyrie, L.D., Jouzel, J. and Bonani, G.  1993.  Correlations between climate records from North Atlantic sediments and Greenland ice.  Nature 365: 143-147.

Bond, G.C. and Lotti, R.  1995.  Iceberg discharges into the North Atlantic on millennial time scales during the last glaciation.  Science 267: 1005-1010.

Bowen, D.Q.  1978.  Quaternary Geology: A Stratigraphic Framework for Multidisciplinary work.  Pergamon Press Ltd., Oxford, UK.

Bowler, J.M., Hope, G.L., Jennings, J.N., Singh, G. and Walker, D.  1976.  Late Quaternary climates of Australia and New Guinea.  Quaternary Research 6: 359-394.

Broecker, W., Bond, G., Klas, M., Clark, E. and McManus, J.  1992.  Origin of the north Atlantic's Heinrich events.  Climate Dynamics 6: 265-273.

CLIMAP Project Members, 1981.  Seasonal reconstruction of the earth's surface at the last glacial maximum.  Geological Society of America Map Chart Series MC-36.

Coleman, A.P.  1969.  Ice Ages Recent and Ancient.  AMS Press, New York, NY.

Crowley, T. J. and North, G.R.  1991.  Paleoclimatology, Oxford University Press, New York, NY.

Crowley, T.J. and Parkinson, C.L.  1988.  Late Pleistocene variations in Antarctic sea ice II: Effect of interhemispheric deep ocean heat exchange.  Climate Dynamics 3: 93-105.

Daly, R.A.  1973.  The Changing World of the Ice Age.  Hafner Press, New York, NY.

Dansgaard, W., White, J.W.C. and Johnsen, S.J.  1989.  The abrupt termination of the Younger Dryas.  Nature 339: 532-534.

Dansgaard, W., Johnsen, S.J., Clausen, H.B., Dahl-Jenden, D., Gunderstrup, N.S., Hammer, C.U., Hvidberg, C.S., Steffensen, J.P., Sveinbjörnsdottir, Jouzel, J. and Bond, G.  1993.  Evidence for general instability of past climate from a 250-kyr ice-core record.  Nature 364: 218-220.

DeAngelis, M., Barkov, N.I. and Petrov, V.N.  1987.  Aerosol concentrations over the last climatic cycle (160 kyr) from an Antarctic ice core.  Nature 325: 318-321.

Delcourt, H.R.  1979.  Late-Quaternary vegetation history of the eastern Highland Rim and adjacent Cumberland Plateau of Tennessee.  Ecological Monographs 49: 255-280.

Delcourt, P.A. and Delcourt, H.R.  1983.  Late-Quaternary vegetational dynamics and community stability reconsidered.  Quaternary Research 19: 265-271.

Delmas, R.J., Ascencio, J.M. and Legrand, M.  1980.  Polar ice evidence that atmospheric CO2 20,000 yr. BP was 50% of present.  Nature 284: 155-157.

Denton, G.H. and Hendy, C.H.  1994.  Younger Dryas age advance of Franz Josef glacier in the southern alps of New Zealand.  Science 264: 1434-1437.

Erickson, J.  1990.  Ice Ages: Past and Future.  TAB BOOKS, Blue Ridge Summit, PA.

Fairbanks, R.G.  1989.  A 17,000-year glacio-eustatic sea level record: Influence of glacial melting rates on Younger Dryas event and deep-ocean circulation.  Nature 342: 637-642.

Flint, R.C.  1957.  Glacial and Pleistocene Geology.  John Wiley and Sons, Inc., New York, NY.

Flint, R.F.  1971.  Glacial and Quaternary Geology.  John Wiley and Sons, New York, NY.

Gaudichet, A., De Angelis, M., Lefever, R., Petit, J.R., Korotkevitch, Y.S. and Petrov, V.N.  1988.  Mineralogy of insoluble particles in the Vostok Antarctic ice core over the last climatic cycle (150 kyr). Geophysical Research Letters 15: 1471-1474.

Grimm, E.C., Jacobson, G.L., Watts, W.A., Hansen, B.C.S. and Maasch, K.A.  1993.  A 50,000-year record of climate oscillations from Florida and its temporal correlation with the Heinrich Events.  Science 261: 198-200.

Grootes, P.M., Stuiver, M., White, J.W.C., Johnsen, S. and Jouzel, J.  1993.  Comparison of oxygen isotope records from the GISP2 and GRIP Greenland ice cores.  Nature 366: 552-554.

Guiot, J., Pons, A., de Beaulieu, J.L. and Reille, M.  1989.  A 140,000-year continental climate reconstruction from two European pollen records.  Nature 338: 309-313.

Guiot, J., de Beaulieu, J.L., Cheddad, R., David, F., Ponel, P. and Reille, M.  1993.  The climate in western Europe during the last glacial interglacial cycle derived from pollen and insect remains.  Palaeogeography, Palaeoclimatology 103: 73-93.

Haffer, J.  1969.  Speciation in Amazonian forest birds.  Science 165: 131-137.

Hamilton, A.C.  1982.  Environmental History of East Africa, A Study of the Quaternary.  Academic Press Inc., New York, NY.

Hammer, C.U., Clausen, H.B., Dansgaard, W., Neftel, A., Kristinsdottir, P and Johnson, E.  1985.  Continuous impurity analysis along Dye 3 deep core.  In: Greenland Ice Core: Geophysics, Geochemistry, and the Environment.  C.C. Langway, H. Oeschger, and W. Dansgaard (Eds.).  Geophysical Monographs 33, American Geophysical Union, Washington, DC, pp. 90-94.

Hastenrath, S.  1971.  On the Pleistocene snowline depression in the arid regions of the South American Andes.  Journal of Glaciology 10: 255-267.

Hastenrath, S.  1985.  Climate and Circulation of the Tropics.  D. Reidel, Dordrecht, The Netherlands.

Herron, M.M and Langway, C.C.  1985.  Chloride, nitrate, and sulfate in the Dye 3 and Camp Century, Greenland ice cores.  In: Greenland Ice Core: Geophysics, Geochemistry, and the Environment.  C.C. Langway, H. Oeschger, and W. Dansgaard (Eds.).  Geophysical Monographs 33, American Geophysical Union, Washington, DC, pp. 77-84.

Houghton, J.T., Jenkins, G.J. and Ephraums, J.J. (Eds.).  1990.  Climate Change: The IPCC Scientific Assessment.  Cambridge University Press, Cambridge, UK.

Houghton, J.T., Miera Filho, L.G., Callander, B.A., Harris, N., Kattenberg, A. and Maskell, K (Eds.).  1996.  Climate Change 1995: The Science of Climate Change.  Cambridge University Press, Cambridge, UK.

Hughes, T.  1996.  Can ice sheets trigger abrupt climate change?  Arctic and Alpine Research 28: 448-465.

Idso, S.B.  1989.  Carbon dioxide, soil moisture, and future crop production.  Soil Science 147: 305-307.

Johnsen, S.J., Clausen, H., Dansgaard, W., Fuhrer, K., Gunderstrup, N.S., Hammer, C.U., Iverssen, P., Jouzel, J., Stauffer, B. and Steffensen, J.P.  1992.  Irregular glacial interstadials recorded in a new Greenland ice core.  Nature 359: 311-313.

Jouzel, J., Vaikmae, R., Petit, J.R., Martin, M., Duclos, Y., Stievenard, M., Lorius, C., Toots, M., Melieres, M.A., Burckle, L.H., Barkov, N.I. and Kotyakov, V.M.  1995.  The two-step shape and timing of the last deglaciation in Antarctica.  Climate Dynamics 11: 151-161.

Knox, F. and McElroy, M.B.  1984.  Changes in atmospheric CO2: Influence of the marine biota at high latitude.  Journal of Geophysical Research 89: 4629-4637.

Legrand, M.R., Lorius, C., Barkov, N.I. and Petrov, V.N.  1988.  Vostok (Antarctica) ice core: Atmospheric chemistry changes over the last climatic cycle (160,000 yr).  Atmospheric Environment 22: 317-331.

Lehman, S.J. and Keigwin, L.D.  1992.  Sudden changes in North Atlantic circulation during the last deglaciation.  Nature 356: 757-762.

Lorius, C., Jouzel, J., Ritz, C., Merlivat, L., Barkov, N.I., Korotkevich, Y.S. and Kotlyakov, V.M.  1985.  A 150,000-year climatic record from Antarctic ice.  Nature 316: 591-596.

Lyle, M.  1988.  Climatically forced organic carbon burial in equatorial Atlantic and Pacific Oceans.  Nature 335: 529-532.

Lyle, M., Murray, D.W., Finney, B.P., Dymond, J., Robbins, J.M. and Brooksforce, K.  1988.  The record of late Pleistocene biogenic sedimentation in the eastern tropical Pacific Ocean.  Paleoceanography 3: 39-59.

Mahaney, W.C.  1990.  Ice on the Equator: Quaternary Geology of Mount Kenya, East Africa.  Wm Caxton Ltd, Sister Bay, WI.

Martin, J.H. and Fitzwater, S.E.  1988.  Iron deficiency limits phytoplankton growth in the north-east Pacific subarctic.  Nature 331: 341-343.

Martin, J.H.  1990.  Glacial-interglacial CO2 change: the iron hypothesis.  Palaeoceanography 5: 1-13.

Martin, J.H.  1992.  Iron as a limiting factor in oceanic productivity.  In: Primary Productivity and Biogeochemical Cycles in the Sea.  P.G. Falkowski and A.D. Woodhead (Eds.).  Plenum, New York, NY, pp. 123-137.

Mayewski, P.A., Meeker, L.D., Whitlow, S., Twicker, M.S., Morrison, M.C., Alley, R.B., Bloomfield, P. and Taylor, K.  1993.  The atmosphere during the Younger Dryas.  Science 262: 195-197.

Mayewski, P.A., Meeker, L.D., Whitlow, S., Twicker, M.S., Morrison, M.C., Grootes, P.M., Bond, G.C., Alley, R.B., Meese, D.A., Gow, A.J., Taylor, K.C., Ram, M. and Wunkes, M.  1994.  Changes in atmospheric circulation and oceanic ice cover over the North Atlantic during the last 41,000 years.  Science 263: 1747-1751.

McElroy, M.B.  1983.  Marine biological controls on atmospheric CO2 and climate.  Nature 302: 328-329.

Muller, P.J., Erlenkeuser, H. and von Grafenstein, R.  1983.  Glacial-interglacial cycles in oceanic productivity inferred from organic carbon contents in eastern North Atlantic sediment cores.  In: Coastal Upwelling: Its Sediment Record. Part B: Sedimentary Records of Ancient Coastal Upwelling.  J. Thiede and E. Suess (Eds.).  Plenum Press, New York, NY, pp. 365-389.

Parkin, D.W. and Shackleton, N.J.  1973.  Trade wind and temperature correlations down a deep-sea core off the Sahara coast.  Nature 245: 455-457.

Pedersen, T.F.  1983.  Increased productivity in the eastern equatorial Pacific during the last glacial maximum (19,000 to 14,000 yr B.P.).  Geology 11: 16-19.

Peltier, W.R.  1987.  Glacial isostasy, mantle viscosity, and Pleistocene climatic change.  In: North America and Adjacent Oceans During the Last Deglaciation.  W.F. Ruddiman and H.E. Wright (Eds.).  The Geology of North America v.3 K-3, Geological Society of America, Boulder, CO, pp. 155-182.

Petit, J.R., Briat, M. and Royer, A.  1981.  Ice age aerosol content from East Antarctic ice core samples and past wind strength.  Nature 293: 391-394.

Petit, J.R., Mounier, L. and Jouzel, J.  1990.  Paleoclimatological and chronological implications of the Vostok core dust record.  Nature 343: 56-58.

Pollard, D.  1978.  An investigation of the astronomical theory of the ice ages using a simple climate-ice sheet model.  Nature 272: 233-235.

Polley, H.W., Johnson, H.B. and Mayeux, H.S.  1992a.  Growth and gas exchange of oats (Avena sativa) and wild mustard (Brassica kaber) at subambient CO2 concentrations.  International Journal of Plant Science 153: 453-461.

Polley, H.W., Johnson, H.B. and Mayeux, H.S.  1992b.  Carbon dioxide and water fluxes of C3 annuals and C3 and C4 perennials at subambient CO2 concentrations.  Functional Ecology 6: 693-703.

Polley, H.W., Johnson, H.B., Marino, B.D. and Mayeux, H.S.  1993.  Increase in C3 plant water-use efficiency and biomass over Glacial to present CO2 concentrations.  Nature 361: 61-64.

Porter, S.C.  1979.  Hawaiian glacial ages.  Quaternary Research 12: 161-187.

Porter, S.C. and An Zhisheng.  1995.  Correlation between climate events in the North Atlantic and China during the last glaciation.  Nature 375: 305-308.

Prance, G.T.  1982.  Forest refuges: Evidence from woody angiosperms.  In: Biological Diversification in the Tropics.  G.T. Prance (Ed.).  Columbia University Press, New York, NY, pp. 137-158.

Preece, R.C.  (Ed.).  1995.  Island Britain: A Quaternary Perspective.  The Geological Society, London, UK.

Rabassa, J.  (Ed.).  1983.  Quaternary of South America and Antarctic Peninsula.  A.A. Balkema, Rotterdam, The Netherlands.

Roger, T. and Wilson, S.  1989.  Carbon dioxide and climate in the Vostok ice core: Why does the system oscillate?  Atmospheric Environment 22: 2637-2638.

Salinger, M.J.  1994.  New Zealand climate in the last 25000 years.  In: Paleoclimates and Climate Modelling.  Proceedings of the National Science Strategy Committee for Climate Change Workshop, Royal Society of New Zealand Miscellaneous Series 29: 15-16.

Salisbury, F.B. and Ross, C.W.  1978.  Plant Physiology.  Woodsworth Publishing Co., Belmont, CA.

Sarnthein, M., Tetzlaff, G., Koopman, B., Walter, K. and Pflaumann, U.  1981.  Glacial and interglacial wind regimes over the east subtropical Atlantic and N.W. Africa.  Nature 293: 193-196.

Schneider, S.H. and Thompson, S.L.  1979.  Ice ages and orbital variations: Some simple theory modeling.  Quaternary Research 12: 188-203.

Suarez, M.J. and Held, I.M.  1976.  Modeling climatic response to orbital parameter variations.  Nature 263: 46-47.

Suggate, R.P.  1990.  Late Pliocene and Quaternary glaciations of New Zealand.  Quaternary Science Reviews 9: 175-197.

Taylor, K.C., Lamorey, G.W., Doyle, G.A., Alley, R.B., Grootes, P.M., Mayewski, P.A., White, J.C.W. and Barlow, L.K.  1993.  The "flickering switch" of late Pliestocene climate change.  Nature 361: 432-436.

Thunell, R.C., Williams, D.F. and Howell, M.  1987.  Atlantic-Mediterranean water exchange during the late Neogene.  Paleoceanography 2: 661-678.

Thunell, R.C., Locke, S.M. and Williams, D.F.  1988.  Glacio-eustatic sea-level control on Red Sea salinity.  Nature 334: 601-604.

Thunell, R.C. and Williams, D.F.  1989.  Glacial-Holocene salinity changes in the Mediterranean Sea: Hydrographic and depositional effects.  Nature 338: 493-496.

Tung-sheng, L.  (Ed.).  1991.  Quaternary Geology and Environment of China.  Science Press, Beijing, China.

Watts, W.A.  1980.  Late-Quaternary vegetation history at White Pond on the inner coastal plain of South Carolina.  Quaternary Research 13: 187-199.

Webb, R.S., Rind, D.H., Lehman, S.J., Healy, R.J. and Sigman, D.  1997.  Influence of ocean heat transport on the climate of the Last Glacial Maximum.  Nature 385: 695-699.

Wells, G.L.  1983.  Late-glacial circulation over central North America revealed by aeolian features.  In: Variations in the Global Water Budget.  A. Street-Perrott, M. Beran and R. Ratcliffe (Eds.).  D. Reidel, Dordrecht, The Netherlands, pp. 317-330.

West, R.G.  1977.  Pleistocene Geology and Biology, with Especial Reference to the British Isles.  Longman Inc., New York, NY.

Whyte, I.D.  1995.  Climatic Change and Human Society. Arnold, London, UK.

Williams, M.A.J., Dunkerley, D.L., De Deckker, P., Kershaw, A.P. and Stokes, T.J.  1993.  Quaternary Environments.  Routledge, Chapman and Hall, Inc., New York, NY.