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| Titel |
Aridity under conditions of increased CO2 |
| VerfasserIn |
Peter Greve, Micheal L. Roderick, Sonia I. Seneviratne |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250132184
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| Publikation (Nr.) |
 EGU/EGU2016-12666.pdf |
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| Zusammenfassung |
| A string of recent of studies led to the wide-held assumption that aridity will increase under
conditions of increasing atmospheric CO2 concentrations and associated global warming.
Such results generally build upon analyses of changes in the ‘aridity index’ (the ratio of
potential evaporation to precipitation) and can be described as a direct thermodynamic effect
on atmospheric water demand due to increasing temperatures. However, there is widespread
evidence that contradicts the ‘warmer is more arid’ interpretation, leading to the ‘global
aridity paradox’ (Roderick et al. 2015, WRR). Here we provide a comprehensive assessment
of modeled changes in a broad set of dryness metrics (primarily based on a range of
measures of water availability) over a large range of realistic atmospheric CO2
concentrations. We use an ensemble of simulations from of state-of-the-art climate
models to analyse both equilibrium climate experiments and transient historical
simulations and future projections. Our results show that dryness is, under conditions of
increasing atmospheric CO2 concentrations and related global warming, generally
decreasing at global scales. At regional scales we do, however, identify areas that
undergo changes towards drier conditions, located primarily in subtropical climate
regions and the Amazon Basin. Nonetheless, the majority of regions, especially in
tropical and mid- to northern high latitudes areas, display wetting conditions in a
warming world. Our results contradict previous findings and highlight the need to
comprehensively assess all aspects of changes in hydroclimatological conditions at the land
surface.
Roderick, M. L., P. Greve, and G. D. Farquhar (2015), On the assessment of aridity with
changes in atmospheric CO2, Water Resour. Res., 51, 5450-5463 |
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