Model Projections of an Imminent Transition to a More Arid Climate in Southwestern North America

Seager, Richard; Ting, Mingfang; Held, Isaac M.; Kushnir, Yochanan; Lu, Jian; Vecchi, Gabriel A.; Huang, Huei-Ping; Harnik, Nili; Leetmaa, Ants; Lau, Ngar Cheung; Li, Cuihua; Velez, Jennifer; Naik, Naomi H.

doi:10.1126/science.1139601

Cited by 1,873 publications

(1,473 citation statements)

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“…In addition, the dust season, defined by the length between the first and last events detected at these sites, has become longer (see section S2 for details), consistent with an earlier onset of dust events reported by Hand et al [2016]. Climate models have robustly predicted an incipient spring drying trend in this region [ Seager et al ., 2007; Cook et al ., 2015; Dai , 2013; Gao et al ., 2014], and the observed dust trend could thus be an early signal of its development.…”

Section: Intensification Of Dust Storm Activitymentioning

confidence: 99%

“…Climate model projections suggest a consistent trend toward an increasingly arid climate in the subtropics, including the southwestern United States [ Schubert et al ., 2004; Seager et al ., 2007; Cook et al ., 2015; Prein et al ., 2016]. The predicted drying trend over arid and semiarid regions aids speculation of more frequent dust storms and even another “Dust Bowl” in the coming decades.…”

Section: Introductionmentioning

confidence: 99%

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Intensified dust storm activity and Valley fever infection in the southwestern United States

Tong

Wang

Gill

et al. 2017

Geophysical Research Letters

176

170

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Climate models have consistently projected a drying trend in the southwestern United States, aiding speculation of increasing dust storms in this region. Long‐term climatology is essential to documenting the dust trend and its response to climate variability. We have reconstructed long‐term dust climatology in the western United States, based on a comprehensive dust identification method and continuous aerosol observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network. We report here direct evidence of rapid intensification of dust storm activity over American deserts in the past decades (1988–2011), in contrast to reported decreasing trends in Asia and Africa. The frequency of windblown dust storms has increased 240% from 1990s to 2000s. This dust trend is associated with large‐scale variations of sea surface temperature in the Pacific Ocean, with the strongest correlation with the Pacific Decadal Oscillation. We further investigate the relationship between dust and Valley fever, a fast‐rising infectious disease caused by inhaling soil‐dwelling fungus (Coccidioides immitis and C. posadasii) in the southwestern United States. The frequency of dust storms is found to be correlated with Valley fever incidences, with a coefficient (r) comparable to or stronger than that with other factors believed to control the disease in two endemic centers (Maricopa and Pima County, Arizona).

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Section: Intensification Of Dust Storm Activitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Intensified dust storm activity and Valley fever infection in the southwestern United States

Tong

Wang

Gill

et al. 2017

Geophysical Research Letters

176

170

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“…Denton et al, 2010). Furthermore, the comparison between AOGCM simulations of the LGM and the paleoclimate data demonstrated that hydrologic quantities such as evapotranspiration, soil moisture and runoff will require additional paleoclimate proxy data to reduce the model uncertainty (Seager et al, 2007;Waliser et al, 2007) The 238 U concentration of the spiked CRM145 was 15.7451 ng/g. The concentration of 236 U was calculated using an error weighted average and was found to be 0.91987 ± 0.00063 ng/g (2σ, MSWD = 0.60, n = 18).…”

Section: Resultsmentioning

confidence: 99%

“…Projecting into the 21 st century, increased anthropogenic greenhouse emissions, primarily CO 2 from fossil fuel combustion, will cause changes in the seasonal and long-term availability of water, shifting the balance between precipitation and evapotranspiration (Seager et al, 2007). Changes in the spatial patterns and amount of rainfall caused by this hydrologic intensification in the climate system will also affect water resources (Meehl et al, 1999;Huntington, 2006), annual snow packs (Mote et al, 2004;Barnett et al, 2005), species migration (Walther et al, 2002), and may result in more extreme weather events such as flooding and drought (Meehl et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

“…However, among AOGCM simulations there is widespread disagreement regarding future shifts in hydrologic parameters, both in the direction of change (e.g. increased or decreased precipitation) and the magnitude of change (Seager et al, 2007;Solomon et al, 2007). At the same time, accurately predicting changes in groundwater and surface water availability for agricultural, urban and industrial uses will become increasingly important.…”

Section: Introductionmentioning

confidence: 99%

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An Assessment of Late Pleistocene to Middle Holocene Lake Level Fluctuations in Surprise Valley, California

Ibarra¹

2018

Preprint

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Knowledge of Earth’s climate history and sensitivity, combined with modeling past and future climate, are central to informing policy decisions regarding future climate change. The hydrologic response to future warming scenarios due to increased anthropogenic CO2 emissions remains uncertain. Freshwater availability in the arid western United States is projected to decrease in availability as increased agricultural, urban and industrial uses continue to stress supplies. Motivated by the potential for dramatic future hydrologic changes, studies recording the abrupt transitions between different equilibrium states of natural past climate variability shed light on our understanding of the modern climate system.The presence of pluvial lakes in the Basin and Range Province, in the western United States, during the late Pleistocene (40 to 10 ka) indicates far greater moisture availability during the Pleistocene glacials. This study investigates the timing and magnitude of the most recent pluvial lake cycle that filled Surprise Valley, California using geophysical, geochemical and geochronologic tools. Spanning 31.2 to 4.6 ka, this new lake level record places the highest lake level, at 180 meters above present day playa, at 13.9 ± 1.2 ka. This age appears to be nearly synchronous with highstands of Lake Lahontan to the south and the Chewaucan Basin to the north. Additionally, most of the Basin and Range lake highstands, including Lake Surprise, follow peaks in precipitation minus evapotranspiration (P-ET) by 8-10 kyr. By compiling a diverse set of paleoclimate data available for western North America, I found that the timing and geographic distribution of lake highstands is inconsistent with increased precipitation in response to shifting westerly winds, the current model for the genesis of large lakes in western North America. Rather, lakes levels are more strongly correlated with changes in summer insolation, suggesting that lake highstands were likely facilitated by colder temperatures and increased humidity due to the presence of continental ice sheets and increased atmospheric convergence. I compared the constraints from lake and soil-based records to Atmosphere-Ocean General Circulation Model simulations from the Paleoclimate Model Intercomparison Project 2. Based on model-proxy intercomparison, the Atmosphere-Ocean General Circulation Models, the same models used to also assess future climatic changes, poorly predict hydrologic quantities for the Last Glacial Maximum.

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Climatic drivers of pinyon mouse Peromyscus truei population dynamics in a resource‐restricted environment

et al. 2019

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Highly variable patterns in temperature and rainfall events can have pronounced consequences for small mammals in resource-restricted environments. Climatic factors can therefore play a crucial role in determining the fates of small mammal populations. We applied Pradel's temporal symmetry model to a 21-year capturerecapture dataset to study population dynamics of the pinyon mouse (Peromyscus truei) in a semi-arid mixed oak woodland in California, USA. We examined time-, season-and sex-specific variation in realized population growth rate (λ) and its constituent vital rates, apparent survival and recruitment. We also tested the influence of climatic factors on these rates. Overall monthly apparent survival was 0.81 AE 0.004 (estimate AE SE). Survival was generally higher during wetter months (October-May) but varied over time. Monthly recruitment rate was 0.18 AE 0.01, ranging from 0.07 AE 0.01 to 0.63 AE 0.07. Although population growth rate (λ) was highly variable, overall monthly growth rate was close to 1.0, indicating a stable population during the study period (λ AE SE = 0.99 AE 0.01). Average temperature and its variability negatively affected survival, whereas rainfall positively influenced survival and recruitment rates, and thus the population growth rate. Our results suggest that seasonal rainfall and variation in temperature at the local scale, rather than regional climatic patterns, more strongly affected vital rates in this population. Discerning such linkages between species' population dynamics and environmental variability are critical for understanding local and regional impacts of global climate change, and for gauging viability and resilience of populations in resource-restricted environments. K E Y W O R D Sapparent survival, capture-mark-recapture, climate change effects, realized population growth rate, recruitment, rodent demography

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Model Projections of an Imminent Transition to a More Arid Climate in Southwestern North America

Cited by 1,873 publications

References 18 publications

Intensified dust storm activity and Valley fever infection in the southwestern United States

Intensified dust storm activity and Valley fever infection in the southwestern United States

An Assessment of Late Pleistocene to Middle Holocene Lake Level Fluctuations in Surprise Valley, California

Climatic drivers of pinyon mouse Peromyscus truei population dynamics in a resource‐restricted environment

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