Temporal and spatial patterns of Holocene dune activity on the Great Plains of North America: megadroughts and climate links

Forman, Steven L.; Oglesby, Robert J.; Webb, Robert S.

doi:10.1016/s0921-8181(00)00092-8

Cited by 237 publications

(231 citation statements)

References 99 publications

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“…Expanded upper and lower treelines (Fall, 1997), northward expansion of C 4 grasses and tropical elements in packrat middens (Van Devender, 1990;McAuliffe and Van Devender, 1998), and climate model output (Rind, 1994;Kutzbach, 1998) all indicate greater-than-modern summer temperatures and precipitation during the mid-Holocene (~8000-4000 yr B.P). In contrast, desiccating or intermittent lakes from the U.S.A.-Mexico borderlands northward (Waters, 1989;Davis and Shafer, 1992;Anderson, 1993;Hasbargen, 1994;Krider, 1998), peak dune activity in the Great Plains (Forman, 2001) and the decline in midden production throughout the southwestern United States (Webb and Betancourt, 1990;Spaulding, 1991) indicate pervasive mid-Holocene winter drought. While warm wet summers and dry winters would tend to favor C 4 grasses over C 3 desert shrubs, we suggest the absence of C 3 desert shrubs during the mid-Holocene was due to colder-than-present winter temperatures prior to ~5000-4000 yr B.P.…”

Section: Mid-to Late Holocenementioning

confidence: 99%

Inferences about winter temperatures and summer rains from the late Quaternary record of C₄ perennial grasses and C₃ desert shrubs in the northern Chihuahuan Desert

Holmgren

Norris

Betancourt

2006

J Quaternary Science

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Late Quaternary histories of two North American desert biomes-C 4 grasslands and C 3 shrublands-are poorly known despite their sensitivity and potential value in reconstructing summer rains and winter temperatures. Plant macrofossil assemblages from packrat midden series in the northern Chihuahuan Desert show that C 4 grasses and annuals typical of desert grassland persisted near their present northern limits throughout the last glacialinterglacial cycle. By contrast, key C 3 desert shrubs appeared somewhat abruptly after 5000 cal yr B.P. Bioclimatic envelopes for select C 4 and C 3 species are mapped to interpret the glacialinterglacial persistence of desert grassland and the mid-to-late Holocene expansion of desert shrublands. The envelopes suggest relatively warm Pleistocene temperatures with moist summers allowed for persistence of C 4 grasses, whereas winters were probably too cold (or too wet) for C 3 desert shrubs. Contrary to climate model results, core processes associated with the

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Section: Mid-to Late Holocenementioning

confidence: 99%

Inferences about winter temperatures and summer rains from the late Quaternary record of C₄ perennial grasses and C₃ desert shrubs in the northern Chihuahuan Desert

Holmgren

Norris

Betancourt

2006

J Quaternary Science

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“…The Dust Bowl drought was likely unique during the instrumental era, but similar drought patterns can be found during the Medieval Climate Anomaly (MCA) (4). Typical North American droughts during the MCA were longer lasting (on the order of decades) and more intense (21), and were accompanied by large-scale dune mobilization over parts of the Great Plains (22). This movement of dunes implies a nearcomplete loss of vegetation cover (in this case induced naturally by an intense and persistent drought) and the possibility of a productive dust source and subsequent aerosol and vegetation feedbacks.…”

mentioning

confidence: 99%

Amplification of the North American “Dust Bowl” drought through human-induced land degradation

Cook

Miller

Seager

2009

Proc. Natl. Acad. Sci. U.S.A.

305

270

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The ''Dust Bowl'' drought of the 1930s was highly unusual for North America, deviating from the typical pattern forced by ''La Nina'' with the maximum drying in the central and northern Plains, warm temperature anomalies across almost the entire continent, and widespread dust storms. General circulation models (GCMs), forced by sea surface temperatures (SSTs) from the 1930s, produce a drought, but one that is centered in southwestern North America and without the warming centered in the middle of the continent. Here, we show that the inclusion of forcing from human land degradation during the period, in addition to the anomalous SSTs, is necessary to reproduce the anomalous features of the Dust Bowl drought. The degradation over the Great Plains is represented in the GCM as a reduction in vegetation cover and the addition of a soil dust aerosol source, both consequences of crop failure. As a result of land surface feedbacks, the simulation of the drought is much improved when the new dust aerosol and vegetation boundary conditions are included. Vegetation reductions explain the high temperature anomaly over the northern U.S., and the dust aerosols intensify the drought and move it northward of the purely oceanforced drought pattern. When both factors are included in the model simulations, the precipitation and temperature anomalies are of similar magnitude and in a similar location compared with the observations. Human-induced land degradation is likely to have not only contributed to the dust storms of the 1930s but also amplified the drought, and these together turned a modest SSTforced drought into one of the worst environmental disasters the U.S. has experienced. dust aerosols ͉ land surface feedbacks

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“…The geologic record provides evidence for widespread and recurrent dune mobilization events during the MCA (Forman et al 2001;Hanson et al 2010;Miao et al 2007), with the most recent events likely occurring during the fourteenth and fifteenth centuries. These events were driven primarily by megadrought-induced vegetation mortality and reductions in vegetation cover.…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…These droughts had significant ecological and societal consequences, causing major disruptions in regional civilizations (e.g., Benson et al 2007a,b;Douglass 1929) and leading to widespread vegetation mortality and dune mobilization (Forman et al 2001;Hanson et al 2010;Miao et al 2007). These so-called megadroughts are not only unprecedented in the instrumental record but are also largely absent in climate reconstructions of the last 500 years.…”

Section: Introductionmentioning

confidence: 99%

“…With less energy available to drive vertical movement of the atmosphere, convection, and precipitation were subsequently reduced. These feedbacks may be especially important to consider for the MCA megadroughts that occurred over the central plains, given the large-scale vegetation mortality, wind erosion, and dust aerosol transport that occurred during this interval, as inferred from records of paleo dunes (Forman et al 2001;Hanson et al 2010;Miao et al 2007).…”

Section: Introductionmentioning

confidence: 99%

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Intensification of North American Megadroughts through Surface and Dust Aerosol Forcing*

et al. 2013

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Tree-ring-based reconstructions of the Palmer drought severity index (PDSI) indicate that, during the Medieval Climate Anomaly (MCA), the central plains of North America experienced recurrent periods of drought spanning decades or longer. These megadroughts had exceptional persistence compared to more recent events, but the causes remain uncertain. The authors conducted a suite of general circulation model experiments to test the impact of sea surface temperature (SST) and land surface forcing on the MCA megadroughts over the central plains. The land surface forcing is represented as a set of dune mobilization boundary conditions, derived from available geomorphological evidence and modeled as increased bare soil area and a dust aerosol source (328-448N, 1058-958W). In the experiments, cold tropical Pacific SST forcing suppresses precipitation over the central plains but cannot reproduce the overall drying or persistence seen in the PDSI reconstruction. Droughts in the scenario with dust aerosols, however, are amplified and have significantly longer persistence than in other model experiments, more closely matching the reconstructed PDSI. This additional drying occurs because the dust increases the shortwave planetary albedo, reducing energy inputs to the surface and boundary layer. The energy deficit increases atmospheric stability, inhibiting convection and reducing cloud cover and precipitation over the central plains. Results from this study provide the first model-based evidence that dust aerosol forcing and land surface changes could have contributed to the intensity and persistence of the central plains megadroughts, although uncertainties remain in the formulation of the boundary conditions and the future importance of these feedbacks.

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Temporal and spatial patterns of Holocene dune activity on the Great Plains of North America: megadroughts and climate links

Cited by 237 publications

References 99 publications

Inferences about winter temperatures and summer rains from the late Quaternary record of C₄ perennial grasses and C₃ desert shrubs in the northern Chihuahuan Desert

Inferences about winter temperatures and summer rains from the late Quaternary record of C₄ perennial grasses and C₃ desert shrubs in the northern Chihuahuan Desert

Amplification of the North American “Dust Bowl” drought through human-induced land degradation

Intensification of North American Megadroughts through Surface and Dust Aerosol Forcing*

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Temporal and spatial patterns of Holocene dune activity on the Great Plains of North America: megadroughts and climate links

Cited by 237 publications

References 99 publications

Inferences about winter temperatures and summer rains from the late Quaternary record of C4 perennial grasses and C3 desert shrubs in the northern Chihuahuan Desert

Inferences about winter temperatures and summer rains from the late Quaternary record of C4 perennial grasses and C3 desert shrubs in the northern Chihuahuan Desert

Amplification of the North American “Dust Bowl” drought through human-induced land degradation

Intensification of North American Megadroughts through Surface and Dust Aerosol Forcing*

Contact Info

Product

Resources

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Inferences about winter temperatures and summer rains from the late Quaternary record of C₄ perennial grasses and C₃ desert shrubs in the northern Chihuahuan Desert

Inferences about winter temperatures and summer rains from the late Quaternary record of C₄ perennial grasses and C₃ desert shrubs in the northern Chihuahuan Desert