CMIP5 projected changes in spring and summer drought and wet conditions over North America

Swain, Sharmistha; Hayhoe, Katharine

doi:10.1007/s00382-014-2255-9

Cited by 136 publications

(91 citation statements)

References 59 publications

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“…Considering only atmosphere-centric drought and aridity metrics (such as PDSI), an approach taken in several recent papers (3,(5)(6)(7)(8)(9)(10)(11)14), the prediction of drought stress in the future is dire. However, studies that use plant-centric metrics (P-E, soil moisture) tend to show a reduced impact (17,(22)(23)(24)(25).…”

Section: Resultsmentioning

confidence: 99%

“…It is commonly inferred that this will cause droughts to become more widespread and severe (2). Many recent studies, however, ignore the impact of rising atmospheric CO 2 on plant water use (3)(4)(5)(6)(7)(8)(9)(10)(11). Plants absorb CO 2 through stomates in their leaves, and simultaneously lose water to the atmosphere by means of transpiration through the same pathway.…”

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confidence: 99%

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Plant responses to increasing CO ₂ reduce estimates of climate impacts on drought severity

Swann

Hoffman

Koven

et al. 2016

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

492

423

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Rising atmospheric CO 2 will make Earth warmer, and many studies have inferred that this warming will cause droughts to become more widespread and severe. However, rising atmospheric CO 2 also modifies stomatal conductance and plant water use, processes that are often are overlooked in impact analysis. We find that plant physiological responses to CO 2 reduce predictions of future drought stress, and that this reduction is captured by using plant-centric rather than atmosphere-centric metrics from Earth system models (ESMs). The atmosphere-centric Palmer Drought Severity Index predicts future increases in drought stress for more than 70% of global land area. This area drops to 37% with the use of precipitation minus evapotranspiration (P-E), a measure that represents the water flux available to downstream ecosystems and humans. The two metrics yield consistent estimates of increasing stress in regions where precipitation decreases are more robust (southern North America, northeastern South America, and southern Europe). The metrics produce diverging estimates elsewhere, with P-E predicting decreasing stress across temperate Asia and central Africa. The differing sensitivity of drought metrics to radiative and physiological aspects of increasing CO 2 partly explains the divergent estimates of future drought reported in recent studies. Further, use of ESM output in offline models may double-count plant feedbacks on relative humidity and other surface variables, leading to overestimates of future stress. The use of drought metrics that account for the response of plant transpiration to changing CO 2 , including direct use of P-E and soil moisture from ESMs, is needed to reduce uncertainties in future assessment.T he demand for water by the atmosphere is widely predicted to increase due to climate change (1). It is commonly inferred that this will cause droughts to become more widespread and severe (2). Many recent studies, however, ignore the impact of rising atmospheric CO 2 on plant water use (3-11). Plants absorb CO 2 through stomates in their leaves, and simultaneously lose water to the atmosphere by means of transpiration through the same pathway. Higher atmospheric CO 2 concentrations allow plants to reduce water losses per unit of carbon gain (12), in part by reducing stomatal conductance when the gradient of CO 2 between the atmosphere and the leaf interior increases. If leaf area stays the same, this physiological response has the potential to reduce water losses from the land surface, increase soil moisture, and reduce plant water stress (13)-the opposite effect of an increase in drought stress and aridity as predicted by many drought metrics (3,14,15). A plant-centric view may therefore suggest that ecosystem-level tradeoffs between water loss and photosynthesis under increasing CO 2 are potentially large enough to reduce drought, despite the large projected increases in water demand from a warmer atmosphere.Drought indices, river routing schemes, and water balance models frequently use potential evapotr...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Plant responses to increasing CO ₂ reduce estimates of climate impacts on drought severity

Swann

Hoffman

Koven

et al. 2016

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

492

423

View full text Add to dashboard Cite

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“…Furthermore, this heavy reliance on winter precipitation supports the use of restoration thinning treatments producing low stand densities to increase tree access to the most important water source: deep soil water recharged by winter precipitation [24]. It is important to identify the seasonal water source for tree growth during summer months and manage forests to maximize this water source to increase tree resistance to the projected hotter and drier climate in the Southwest [6][7][8][9][10]. As the influence of climate change on precipitation seasonality and forest productivity is not an issue unique to ponderosa pine forests or the Southwest, our findings may inform understanding and management of other semi-arid forest ecosystems.…”

Section: Discussionmentioning

confidence: 99%

“…Understanding the relative importance of winter and monsoon precipitation on tree growth in the USA Southwest is important, as drought-induced forest mortality is widespread [1][2][3][4][5] and the region will likely dry substantially in the next century [6][7][8][9][10]. Likely reductions in winter snow in the western USA [11][12][13][14] will decrease winter recharge of forest soils, and projected earlier spring snowmelt will likely increase growing season length [15] and forest water demand.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Monsoon Climate on Latewood Growth of Southwestern Ponderosa Pine

Kerhoulas

Kolb

Koch

2017

Forests

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Abstract:The North American Monsoon delivers warm season precipitation to much of the southwestern United States, yet the importance of this water source for forested ecosystems in the region is not well understood. While it is widely accepted that trees in southwestern forests use winter precipitation for earlywood production, the extent to which summer (monsoon season) precipitation supports latewood production is unclear. We used tree ring records, local climate data, and stable isotope analyses (δ 18 O) of water and cellulose to examine the importance of monsoon precipitation for latewood production in mature ponderosa pine (Pinus ponderosa Dougl.) in northern Arizona. Our analyses identified monsoon season vapor pressure deficit (VPD) and Palmer Drought Severity Index (PDSI) as significant effects on latewood growth, together explaining 39% of latewood ring width variation. Stem water and cellulose δ 18 O analyses suggest that monsoon precipitation was not directly used for latewood growth. Our findings suggest that mature ponderosa pines in this region utilize winter precipitation for growth throughout the entire year. The influence of monsoon precipitation on growth is indirect and mediated by its effect on atmospheric moisture stress (VPD). Together, summer VPD and antecedent soil moisture conditions have a strong influence on latewood growth.

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“…Changes in the streamflow could be associated with a future decrease in precipitation intensity, increase in the number of dry days across the south-east, and an increase in the average temperature. Swain and Hayhoe [37] reported statistically significant increases in the mean spring standard precipitation index (SPI) over the northern part of the North American continent. Earlier studies have estimated a similar magnitude of change in river flow for the near, mid and long-term future.…”

Section: Discussionmentioning

confidence: 99%

Streamflow Simulation Using Bayesian Regression with Multivariate Linear Spline to Estimate Future Changes

Bhowmik

Seo

Sahoo³

2018

Water

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Statistical models for hydrologic simulation are a common choice among researchers particularly when catchment information is limited. In this study, we adopt a new statistical approach, namely Bayesian regression with multivariate linear spline (BMLS) for long-term simulation of streamflow on a Hydroclimate Data Network (HCDN) site in the United States. The study aims to: (i) evaluate the performance of the BMLS model; (ii) compare the performance of climate model outputs as predictors in hydrologic simulation; and (iii) estimate the changes in streamflow caused by anthropogenic climate change which is defined as the projected change in precipitation and temperature under different greenhouse gas emission scenarios. Performance of the BMLS model is compared with climatology for the validation period. Results suggest that the BMLS model forced with observed monthly precipitation and average temperature exhibits information that is not presented in the climatology of the validation period. Later, we consider Coupled Model Intercomparison Project Phase 5 (CMIP5) historical and hindcast runs to simulate streamflow at the HCDN site. The study found that sea-surface temperature-initialized decadal hindcast runs are performing no better than 20th century historical runs regarding hydrologic simulation. Finally, the changes in mean and variability in streamflow at the HCDN site are estimated by forcing the model with CMIP5 future projections for the period 2000-2049.

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CMIP5 projected changes in spring and summer drought and wet conditions over North America

Cited by 136 publications

References 59 publications

Plant responses to increasing CO ₂ reduce estimates of climate impacts on drought severity

Plant responses to increasing CO ₂ reduce estimates of climate impacts on drought severity

The Influence of Monsoon Climate on Latewood Growth of Southwestern Ponderosa Pine

Streamflow Simulation Using Bayesian Regression with Multivariate Linear Spline to Estimate Future Changes

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CMIP5 projected changes in spring and summer drought and wet conditions over North America

Cited by 136 publications

References 59 publications

Plant responses to increasing CO 2 reduce estimates of climate impacts on drought severity

Plant responses to increasing CO 2 reduce estimates of climate impacts on drought severity

The Influence of Monsoon Climate on Latewood Growth of Southwestern Ponderosa Pine

Streamflow Simulation Using Bayesian Regression with Multivariate Linear Spline to Estimate Future Changes

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Plant responses to increasing CO ₂ reduce estimates of climate impacts on drought severity

Plant responses to increasing CO ₂ reduce estimates of climate impacts on drought severity