Evaluating Uncertainties in the Projection of Future Drought

Burke, Eleanor J.; Brown, Simon J.

doi:10.1175/2007jhm929.1

Cited by 226 publications

(198 citation statements)

References 18 publications

Supporting

Mentioning

186

Contrasting

Unclassified

Order By: Relevance

“…4a,b). In contrast, and consistent with other studies 21 , soil moisture was projected to increase at some sites but remained unchanged at others, with small overall changes relative to intermodel variability (Fig. 4a,b).…”

supporting

confidence: 91%

“…VPD is highly sensitive to changes in air temperature and is thus expected to rise globally in the future 1,20 . On the other hand, projected changes in precipitation and soil moisture are less certain, more spatially variable, and smaller in relative magnitude 21 . As a result, soil moisture and VPD will probably become more decoupled, which could cause the ecological impacts of droughts to diverge even further from our present understanding.…”

mentioning

confidence: 99%

See 1 more Smart Citation

The increasing importance of atmospheric demand for ecosystem water and carbon fluxes

et al. 2016

View full text Add to dashboard Cite

Soil moisture supply and atmospheric demand for water independently limit-and profoundly a ect-vegetation productivity and water use during periods of hydrologic stress [1][2][3][4] . Disentangling the impact of these two drivers on ecosystem carbon and water cycling is di cult because they are often correlated, and experimental tools for manipulating atmospheric demand in the field are lacking. Consequently, the role of atmospheric demand is often not adequately factored into experiments or represented in models 5-7 . Here we show that atmospheric demand limits surface conductance and evapotranspiration to a greater extent than soil moisture in many biomes, including mesic forests that are of particular importance to the terrestrial carbon sink 8,9 . Further, using projections from ten general circulation models, we show that climate change will increase the importance of atmospheric constraints to carbon and water fluxes in all ecosystems. Consequently, atmospheric demand will become increasingly important for vegetation function, accounting for >70% of growing season limitation to surface conductance in mesic temperate forests. Our results suggest that failure to consider the limiting role of atmospheric demand in experimental designs, simulation models and land management strategies will lead to incorrect projections of ecosystem responses to future climate conditions. Ecosystem moisture stress is often characterized by changes in soil water availability 10,11 . Declining soil moisture impedes the movement of water to evaporating sites at the soil or leaf surface 12 , reducing the surface conductance to water vapour (G S )-a key determinant of carbon and water cycling-and thereby evapotranspiration (ET). However, atmospheric demand for water, which is directly related to the atmospheric vapour pressure deficit (VPD), also affects G S and ET. Plants close their stomata to prevent excessive water loss when VPD is high [13][14][15][16] and thus, increases in VPD during periods of hydrologic stress represent an independent constraint on plant carbon uptake and water use in ecosystems.While the plant physiological community has long recognized the critical role of VPD in determining plant functioning, VPD is often overlooked in many fields of hydrologic and climate science. For example, precipitation manipulation experiments are frequently used to draw conclusions about ecosystem response to drought stress, even though VPD is unaffected by precipitation manipulation 10 . Some terrestrial ecosystem and ecohydrological models do not permit stomatal conductance to vary with atmospheric demand 5,11 . Many models designed to capture these impacts rely on empirical parameterizations for soil moisture and VPD stress that promote compensating effects and model equifinality 5 , and/or use relative humidity instead of VPD as the primary driver, with significant consequences for projections of

show abstract

supporting

confidence: 91%

mentioning

confidence: 99%

The increasing importance of atmospheric demand for ecosystem water and carbon fluxes

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Note that the partial discrepancies of changes in dryness assessed either by analysis of CDD or soil moisture highlight that the choice of dryness index can be critical for the assessment of drought projections (see also Burke and Brown 2008). In the case of the projected annual changes in CDD, the close agreement between the patterns in T06 and our analyses demonstrate their robustness for different emission scenarios, at least for the regions where the models reasonably agree on the sign of the changes.…”

Section: Drynesssupporting

confidence: 59%

Global changes in extreme events: regional and seasonal dimension

2011

View full text Add to dashboard Cite

This study systematically analyzes the complete IPCC AR4 (CMIP3) ensemble of GCM simulations with respect to changes in extreme event characteristics at the end of the 21st century compared to present-day conditions. It complements previous studies by investigating a more comprehensive database and considering seasonal changes beside the annual time scale. Confirming previous studies, the agreement between the GCMs is generally high for temperature-related extremes, indicating increases of warm day occurrences and heatwave lengths, and decreases of cold extremes. However, we identify issues with the choice of indices used to quantify heatwave lengths, which do overall not affect the sign of the changes, but strongly impact the magnitude and patterns of projected changes in heatwave characteristics. Projected changes in precipitation and dryness extremes are more ambiguous than those in temperature extremes, despite some robust features, such as increasing dryness over the Mediterranean and increasing heavy precipitation over the Northern high latitudes. We also find that the assessment of projected changes in dryness depends on the index choice, and that models show less agreement regarding changes in soil moisture than in the commonly used 'consecutive dry days' index, which is based on precipitation data only. Finally an analysis of the scaling of changes of extreme temperature quantiles with global, regional and seasonal warming shows that much of the extreme quantile changes are due to a seasonal scaling of the regional annual-mean warming. This emphasizes the importance of the seasonal time scale also for extremes. Changes in extreme quantiles of temperature on land scale with changes in global annual mean temperature by a factor of more than 2 in some regions and seasons, implying large changes in extremes in several countries, even for the commonly discussed global 2• C-warming target.

show abstract

“…Studies have begun to address such uncertainties by incorporating two or more climate models to investigate the significance for drought projections (e.g. Sheffield and Wood 2008;Burke and Brown 2008), or two or more emission scenarios to investigate the importance of emission trajectories (e.g. Sheffield and Wood 2008;Vasiliades et al 2009).…”

mentioning

confidence: 99%

Quantifying the impact of climate change on drought regimes using the Standardised Precipitation Index

Jenkins

Warren

2014

Theor Appl Climatol

View full text Add to dashboard Cite

The study presents a methodology to characterise short or long-term drought events, designed to aid understanding of how climate change may affect future risk. An indicator of drought magnitude, combining parameters of duration, spatial extent, and intensity, is presented based on the Standardised Precipitation Index (SPI). The SPI is applied to observed (1955-2003) and projected (2003-2050) precipitation data from the Community Integrated Assessment System (CIAS). Potential consequences of climate change on drought regimes in Australia, Brazil, China, Ethiopia, India, Spain, Portugal and the USA are quantified. Uncertainty is assessed by emulating a range of global circulation models to project climate change. Further uncertainty is addressed through the use of a high emissions scenario and a low stabilisation scenario representing a stringent mitigation policy.Climate change was shown to have a larger effect on the duration and magnitude of long-term droughts, and Australia, Brazil, Spain, Portugal and the USA were highlighted as being particularly vulnerable to multi-year drought events, with the potential for drought magnitude to exceed historical experience. The study highlights the characteristics of drought which may be more sensitive under climate change. For example, on average short-term droughts in the USA do not become more intense but are projected to increase in duration. Importantly, the stringent mitigation scenario had limited effect on drought regimes in the first half of the 21 st century,showing that adaptation to drought risk will be vital in these regions.

show abstract

Evaluating Uncertainties in the Projection of Future Drought

Cited by 226 publications

References 18 publications

The increasing importance of atmospheric demand for ecosystem water and carbon fluxes

The increasing importance of atmospheric demand for ecosystem water and carbon fluxes

Global changes in extreme events: regional and seasonal dimension

Quantifying the impact of climate change on drought regimes using the Standardised Precipitation Index

Contact Info

Product

Resources

About