We present evidence from a variety of physical and biological proxies for a severe drought that affected the mid-continent of North America between 4.1 and 4.3 ka. Rapid climate changes associated with the event had large and widespread ecological effects, including dune reactivation, forest fires and long-term changes in forest composition, highlighting a clear ecological vulnerability to similar future changes. Drought is also documented in the Middle East and portions of Africa and Asia, where it was similar in timing, duration and magnitude to that recorded in the central North American records. Some regions at high latitudes, including northern Europe and Siberia, experienced cooler and/or wetter conditions. Widespread mid-latitude and subtropical drought, associated with increased moisture at some high latitudes, has been linked in the instrumental record to an unusually steep sea surface temperature (SST) gradient between the tropical eastern and western Pacific Ocean (La Ninia) and increased warmth in other equatorial oceans. Similar SST patterns may have occurred at 4.2 ka, possibly associated with external forcing or amplification of these spatial modes by variations in solar irradiance or volcanism. However, changes in SST distribution bracketing the 4.2 ka event are poorly known in most regions and data are insufficient to estimate magnitude of changes in solar and volcanic forcing at this time. Further research is needed to delineate geographical patterns of moisture changes, ecological responses, possible forcing mechanisms and climatology of this severe climatic event.
Ammann, B. , Birks, H.J.B. , Brooks, S.J. , Eicher, U. , von Grafenstein, U. , Hoffman, W. , Lemdahl, G. , Schwander, J. , Tobolski, K. and Wick, L.2000: Quantification of biotic responses to rapid climatic changes around the Younger Dryas-a synthesis . Palaeogeography, Palaeoclimatology, Palaeoecology159, 313-347 .
3.
Ammann, C.M. and Naveau, P.2003: Statistical analysis of tropical explosive volcanism occurrences over the last 6 centuries . Geophysical Research Letters30, no. 5, 1210-1210 , doi:l0.1029/ 2002GLO16388.
4.
Ammann, C.M. , Meehl, G. , Washington, W. and Zender, C.2003: A monthly and latitudinally varying volcanic forcing dataset in simulations of 20th century climate . Geophysical Research Letters30, no. 12, 1657-1657 , doi:10.1029/2003GLO16875.
5.
Baedke, S.J. and Thompson, T.A.2000: A 4,700-year record of lake level and isostasy for Lake Michigan . Journal of Great Lakes Research26, 416-426 .
6.
Baker, R.G. , Bettis, E.A., III , Denniston, R.F. , Gonzalez, L.A. , Strickland, L.E. and Kreig, J.R.2002: Holocene paleoenvironments in southeastern Minnesota-chasing the prairie-forest ecotone . Palaeogeography, Palaeoclimatology, Palaeoecology177, 103-122 .
7.
Barber, K.E. , Chambers, F.M. and Maddy, D.2003: Holocene palaeoclimates from peat stratigraphy: macrofossil proxy climate records from three oceanic raised bogs in England and Ireland . Quaternary Science Reviews22, 521-539 .
8.
Bar-Matthews, M. , Ayalon, A. and Kaufman, A.1997: Late Quaternary paleoclimate in the eastern Mediterranean region from stable isotope analysis of speleothems at Soreq Cave, Israel . Quaternary Research46, 155-168 .
9.
Benson, L. , Burdett, J. , Lund, S. , Kashgarian, M. and Mensing, S.1997: Nearly synchronous climate change in the Northern Hemisphere during the last glacial termination . Nature388, 263-265 .
10.
Bond, G. , Kromer, B. , Beer, J. , Muscheler, R. , Evans, M.N. , Showers, W. , Hoffmann, S. , Lotti-bond, R. , Hajdas, I. and Bonani, G.2001: Persistent solar influence on North Atlantic climate during the Holocene . Science294, 2130-2136 .
11.
Booth, R.K.2002: Testate amoebae as paleoindicators of surfacemoisture changes on Michigan peatlands: modern ecology and hydrological calibration . Journal of Paleolimnology28, 329-348 .
12.
Booth, R.K. and Jackson, S.T.2003a: A high-resolution record of late Holocene moisture variability from a Michigan raised bog . The Holocene13, 865-878 .
13.
Booth, R.K. and Jackson, S.T.2003b: Influence of late Holocene moisture variability on forest dynamics in the western Great Lakes region. Abstracts of the 2003 Ecological Society of America Meeting, Savannah GA. Washington DC: Ecological Society of America , p. 38-38.
14.
Booth, R.K. , Jackson, S.T. and Gray, C.E.D.2004: Paleoecology and high-resolution paleohydrology of a kettle peatland in Upper Michigan . Quaternary Research61, 1-13 .
15.
Bradbury, J.P. and Dieterich-Rurup, V.1993: Holocene diatom paleolimnology of Elk Lake, Minnesota. In Bradbury, J.P. and Dean, W.E. , editors, Elk Lake, Minnesota: evidence for rapid climate change in the north-central United States. Colorado: Geological Society of America Special Paper 276, 215-237.
16.
Bryson, R.A.1988: Late Quaternary volcanic modulation of Milankovitch climate forcing . Theoretical and Applied Climatology39, 115-125 .
17.
Carrion, J.S.2002: Patterns and processes of Late Quaternary environmental change in a montane region of southwestern Europe . Quaternary Science Reviews21, 2047-2066 .
18.
Charman, D.J. and Hendon, D.2000: Long-term changes in soil water tables over the past 4500 years: relationships with climate and North Atlantic atmospheric circulation and sea surface temperature . Climatic Change47, 45-59 .
19.
Claussen, M. , Kubatzki, C. , Brovkin,V. , Ganopolski, A. , Hoelzmann, P. and Pachur, H.J.1999: Simulation of an abrupt change in Saharan vegetation at the end of the mid-holocene . Geophysical Research Letters24, 2037-2040 .
20.
Crowley, T.J.2000: Causes of climate change over the past 1000 years . Science289, 270-277 .
21.
Cullen, H.M. , deMenocat, P.B. , Hemming, S. , Hemming, G. , Brown, F.H. , Guilderson, T. and Sirocko, F.2000: Climate change and the collapse of the Akkadian empire: evidence from the deep sea . Geology28, 379-382 .
22.
Dalfes, H.N. , Kukla, G. and Weiss, H. , editors 1997: Third millennium B.C. climate change and Old World collapse, Volume 49. Berlin: Springer , 723-723 pp.
23.
Damnati, B.2000: Holocene lake records in the Northern Hemisphere of Africa . Journal of African Earth Sciences31, 253-262 .
24.
Davis, M.B. , Calcote, R.R. , Sugita, S. and Takahara, H.1998: Patchy invasion and the origin of a hemlock-hardwoods forest mosaic . Ecology79, 2641-2659 .
25.
Dean, W.E.1993: Physical properties, mineralogy, and geochemistry of Holocene varved sediments of Elk Lake, Minnesota: evidence for rapid climate change in the northcentral United States. In Bradbury, J.P. and Dean, W.E. , editors, Elk Lake, Minnesota: evidence for rapid climate change in the northcentral United States. Colorado: Geological Society of America Special Paper 276, 135-328.
26.
Dean, W.E.1997: Rates, timing, and cyclicity of Holocene eolian activity in north-central United States: evidence from varved lake sediments . Geology25, 331-334 .
27.
DeMenocal, P.B.2001: Cultural responses to climate change during the late Holocene . Science292, 667-673 .
28.
Denniston, R.F. , Gonzalez, L.A. , Asmerom, Y. , Baker, R.G. , Reagan, M.K. and Bettis, E.A., III1999: Evidence for increased cool season moisture during the middle Holocene . Geology27, 815-818 .
29.
Enfield, D.B. , Mestas-Nunez, A.M. and Trimble, P.J.2001: The Atlantic multidecadal oscillation and its relation to rainfall and river flows in the continental U.S . Geophysical Research Letters28, 2077-2080 .
30.
Forman, S. , Oglesby, R. and Webb, R.S.2001: Temporal and spatial patterns of Holocene dune activity on the Great Plains of North America: megadroughts and climate links . Global and Planetary Change29, 1-29 .
31.
Forman, S.L. , Oglesby, R. , Markgraf, V. and Stafford, T.1995: Paleoclimatic significance of late Quaternary eolian deposition on the Piedmont and High Plains, central United States . Global and Planetary Change11, 35-55 .
32.
Frumkin, A. , Kadan, G. , Enzel, Y. and Eyal, Y.2001: Radiocarbon chronology of the Holocene Dead Sea: attempting a regional correlation . Radiocarbon43, 1179-1189 .
33.
Fye, F.K. , Stahle, D.W. and Cook, E.R.2003: Paleoclimatic analogs to twentieth-century moisture regimes across the United States . Bulletin of the American Meteorological Society84, 901-909 .
34.
Gasse, F.2000: Hydrological changes in the African tropics since the Last Glacial Maximum . Quaternary Science Reviews19, 189-211 .
35.
Gasse, F. and Van Campo, E.1994: Abrupt post-glacial climate events in west Asia and north Africa monsoon domains . Earth and Planetary Science Letters126, 435-456 .
36.
Gray, S.T. , Betancourt, J.L. , Fastie, C.L. and Jackson, S.T.2003: Patterns and sources of multidecadal oscillations in drought-sensitive tree-ring records from the central and southern Rocky Mountains . Geophysical Research Letters30, 1316-1319 .
37.
Gupta, A.K. , Anderson, D.M. and Overpeck, J.T.2003: Abrupt changes in the Asian Southwest Monsoon during the Holocene and their links to the North Atlantic Ocean . Nature421, 354-357 .
38.
Hodell, D.A. , Curtis, J.H. and Brenner, M.1995: Possible role of climate in the collapse of Classic Maya civilization . Nature375, 391-394 .
39.
Hoerling, M. and Kumar, A.2003: A perfect ocean for drought . Science299, 691-694 .
40.
Hong, Y.T. , Hong, B. , Lin, Q.H. , Zhu, Y.X. , Shibata, Y. , Hirota, M. , Uchida, M. , Leng, X.T. , Jiang, H.B. , Xu, H. , Wang, H. and Yi, L.2003: Correlation between Indian summer monsoon and North Atlantic climate during the Holocene . Earth and Planetary Science Letters211, 371-380 .
41.
Hughes, P.D.M. , Mauquoy, D. , Barber, K.E. and Langdon, P.G.2000: Mire-development pathways and palaeoclimatic records from a full Holocene peat archive at Walton Moss, Cumbria, England . The Holocene10, 465-479 .
42.
Jalut, G. , Amat, A.E. , Bonnet, L. , Gauquelin, T. and Fontugne, M.2000: Holocene climatic changes in the western Mediterranean, from south-east France to south-east Spain . Palaeogeography, Palaeoclimatology, Palaeoecology160, 255-290 .
43.
Knox, J.C. and Kundzewicz, Z.W.1997: Extreme hydrological events, palaeo-information and climate change . Hydrological Sciences Journal42, 765-779 .
44.
Korhola, A. , Weckstrom, J. , Holmstrom, L. and Erasto, P.2000: A quantitative Holocene climatic record from diatoms in northern Fennoscandia . Quaternary Research54, 284-294 .
45.
Korhola, A. , Vasko, K. , Toivonen, H.T.T. and Olander, H.2002: Holocene temperature changes in northern Fennoscandia reconstructed from chironomids using Bayesian modeling . Quaternary Science Reviews21, 1841-1860 .
46.
Kreig, J. , Bettis, E.A.I. and Forman, S.L.2004: Evidence for late Holocene eolian sand reactivation in the Green liver Lowland, northwestern Illinois: regional response to drought and potential implications . Geological Society of America Abstracts with Programs36, 70-70 . Retrieved 6 January 2005 from http://gsa.confex.com/gsa/200qsfinalprogram/abstract_78748.ht
47.
Laing, T.E. and Smol, J.P.2003: Late Holocene environmental changes inferred from diatoms in a lake on the western Taimyr Peninsula, northern Russia . Journal of Paleolimnology30, 231-247 .
48.
Loope, D.B. , Swinehart, J.B. and Mason, J.P.1995: Dune-dammed paleovalleys of the Nebraska Sand Hills: intrinsic versus climatic controls on the accumulation of lake and marsh sediments . Geological Society of America107, 396-406 .
49.
Magny, M.2004: Holocene climate variability as reflected by midEuropean lake-level fluctuations and its probable impact on prehistoric human settlements . Quaternary International113, 65-79 .
50.
Magri, D. and Parra, I.2002: Late Quaternary western Mediterranean pollen records and African winds . Earth and Planetary Science Letters200, 401-408 .
51.
Mason, J.P. , Swinehart, J.B. and Loope, D.B.1997: Holocene history of lacustrine and marsh sediments in a dune-blocked drainage, southwestern Nebraska Sand Hills, USA . Journal of Paleolimnology17, 67-83 .
52.
McCabe, G.J. , Palecki, M.A. and Betancourt, J.L. 2004: Pacific and Atlantic Ocean influences on multi-decadal drought frequency in the United States . Proceedings of the National Academy of Sciences 101, 4136-4141 .
53.
Meehl, G.A. , Washington, W.M. , Wigley, T.M.L. , Arblaster, J.M. and Dai, A.2003: Solar and greenhouse gas forcing and climate response in the twentieth century . Journal of Climate16, 426-444 .
54.
Menking, K.M. and Anderson, R.Y.2003: Contributions of La Nina and El Nino to middle Holocene drought and late Holocene moisture in the American Southwest . Geology31, 937-940 .
55.
Moy, C.M. , Seltzer, G.O. , Rodbell, D.T. and Anderson, D.M.2002: Variability of El Nifio/Southern Oscillation activity at millennial timescales during the Holocene epoch . Nature420, 162-165 .
56.
Narcisi, B.2000: Late Quaternary eolian deposition in central Italy . Quaternary Research54, 246-252 .
57.
Overpeck, J. and Webb, R. 2000: Nonglacial rapid climate events: past and future . Proceedings of the National Academy of Science 97, 1335-1338 .
58.
Pantaleon-Cano, J. , Errikarta-Imanol, Y. , Perez-Obiol, R. and Roure, J.M.2003: Palynological evidence for vegetational history in semi-arid areas of the western Mediterranean (Almeria, Spain) . The Holocene13, 109-113 .
59.
Peteet, D. , Del Genio, A. and Lo, K.K.-W.1997: Sensitivity of northern hemisphere air temperatures and snow expansion to North Pacific sea surface temperatures in the Goddard Institute for Space Studies general circulation model . Journal of Geophysical Research102, 23781-23791 .
60.
Plunkett, G.M. , Whitehouse, N.J. , Hall, V.A. , Brown, D.M. and Baillie, M.G.L.2004: A precisely-dated lake-level rise marked by diatomite formation in northeastern Ireland . Journal of Quaternary Science19, 3-7 .
61.
Porinchu, D.F. and Cwynar, L.C.2002: Late-Quaternary history of midge communities and climate from a tundra site near the lower Lena river, Northeast Siberia . Journal of Paleolimnology27, 59-69 .
62.
Rind, D. , Shindell, D. , Perlwitz, J. and Lerner, J.2004: The relative importance of solar and anthropogenic forcing of climate change between the Maunder Minimum and the Present . Journal of Climate17, 906-929 .
63.
Rosen, P. , Segerstrom, U. , Eriksson, L. , Renberg, I. and Birks, H.J.B.2001: Holocene climatic change reconstructed from diatoms, chironomids, pollen and near-infrared spectroscopy at an alpine lake (Sjuodjijaure) in northem Sweden . The Holocene11, 551-562 .
64.
Schubert, S.D. , Suarez, M.J. , Pegion, P.J. , Koster, R.D. and Bachmeister, J.T.2004a: Causes of long-term drought in the U.S. Great Plains . Journal of Climate17, 485-503 .
65.
Schubert, S.D. , Suarez, M.J. , Pegion, P.J. , Koster, R.D. and Bachmeister, J.T.2004b: On the cause of the 1930s dust bowl . Science303, 1855-1859 .
66.
Shindell, D.T. , Schmidt, G.A. , Miller, R.L. and Mann, M.E.2003: Volcanic and solar forcing of climate change during the preindustrial era . Journal of Climate16, 4094-4107 .
67.
Shuman, B. , Bartlein, P. , Logar, N. , Newby, P. and Webb, T., HI2002: Parallel climate and vegetation responses to the early Holocene collapse of the Laurentide Ice Sheet . Quaternary Science Reviews21, 1793-1805 .
68.
Stahle, D.W. , Cook, E.R. , Cleaveland, M.K. , Therrell, M.D. , Meko, D.M. , Grissino-Mayer, H.D. , Watson, E. and Luckman, B.H.2000: Tree-ring data document 16th century megadrought over North America . EOS Transactions of the American Geophysical Union81, 121-125 .
69.
Stanley, J.D. , Krom, M.D. , Cliff, R.A. and Woodward, J.C.2003: Nile flow failure at the end of the Old Kingdom, Egypt: strontium isotopic and petrologic evidence . Geoarchaeology18, 395-402 .
70.
Staubwasser, M. , Sirocko, F. , Grootes, P.M. and Segl, M.2003: Climate change at the 4.2 ka BP termination of the Indus valley civilization and Holocene south Asian monsoon variability . Geophysical Research Letters30, 1425-1428 .
71.
Stokes, S. and Gaylord, D.R.1993: Optical dating of Holocene dune sands in the Ferris Dune Field, Wyoming . Quaternary Research39, 274-281 .
72.
Stokes, S. and Swinehart, J.B.1997: Middle-and late-Holocene dune reactivation in the Nebraska Sand Hills, USA . The Holocene7, 263-272 .
73.
Swezey, C.2001: Eolian sediment responses to Late Quaternary climate changes: temporal and spatial patterns in the Sahara . Palaeogeography, Palaeoclimatology, Palaeoecology167, 119-155 .
74.
Thompson, L.G. , Mosley-Thompson, E. , Davis, M.E. , Henderson, K.A. , Brecher, H.H. , Zagorodnov, V.S. , Mashiotta, T.A. , Lin, P. , Mikhalenko, V.N. , Hardy, D.R. and Beer, J.2002: Kilimanjaro ice core records: evidence of Holocene climate change in tropical Africa . Science298, 589-593 .
75.
Tinner, W. and Lotter, A.F.2001: Central European vegetation response to abrupt climate change at 8.2 ka . Geology29, 551-554 .
76.
Weiss, H. , Courty, M.-A. , Wetterstrom, W. , Guichard, F. , Senior, L. , Meadow, R. and Curnow, A.1993: The genesis and collapse of third millennium north Mesopotamian civilization . Science261, 995-1004 .
77.
Wenxiang, W. and Tungsheng, L.2004: Possible role of the 'Holocene Event 3' on the collapse of Neolithic Cultures around the Central Plain of China . Quaternary International117, 153-166 .
78.
Williams, J.W. , Levesque, A.J. , Post, D.M. , Cwynar, L.C. and Lotter, A.F.2002: Rapid and widespread vegetation responses to past climate change in the North Atlantic region . Geology30, 971-974 .
79.
Woodhouse, C.A. and Overpeck, J.T.1998: 2000 years of drought variability in the central United States . Bulletin of the American Meteorological Society79, 2693-2714 .
80.
Woodland, W.A. , Charman, D.J. and Sims, P.C.1998: Quantitative estimates of water tables and soil moisture in Holocene peatlands from testate amoebae . The Holocene8, 261-273 .
81.
Yu, Z.2000: Ecosystem response to Lateglacial and early Holocene climate oscillations in the Great Lakes region of North America . Quaternary Science Reviews19, 1723-1747 .
82.
Yu, Z. , Ito, E. , Engstrom, D.R , and Fritz, S.C.2002: A 2100-year trace-element and stable-isotope record at decadal resolution from Rice Lake in the Northern Great Plains, USA . The Holocene12, 605-617 .
83.
Yu, Z. , Campbell, I.D. , Campbell, C. , Vitt, D.H. , Bond, G.C. and Apps, M.J.2003: Carbon sequestration in western Canadian peat highly sensitive to Holocene wet-dry climate cycles at millennial timescales . The Holocene13, 801-808 .
84.
Zielinski, G.A.2000: Use of paleo-records in determining variability within the volcanism-climate system . Quaternary Science Reviews19, 417-438 .
