Titre :	Global climate change and water resources
Type de document :	texte imprimé
Auteurs :	John T. Hayes, Auteur
Editeur :	Chapman and Hall
Année de publication :	1991
Importance :	p 18-42
Langues :	Anglais (eng)
Catégories :	SCIENCES DE L'ENVIRONNEMENT
Mots-clés :	CHANGEMENT CLIMATIQUE  GENERAL CIRCULATION MODELS (GCM)  EFFET DE SERRE  RESSOURCES D’EAU  HYDROLOGIE
Résumé :	The global rise of atmosphere CO² and other trace gases alter temperature and therefore, precipitation. Together, these change global, as well as regional climates and hydrology. Evapotranspiration, soil moisture content, surface runoff, groundwater recharge, seasonal snowfall, timing of snowmelt periods, river flows, lake levels, hydrologic variability and sensitivity, natural and artificial storage and seal-level rise and associated coastal flooding will all be affected. Although there may be a growing consensus among climate modelers that a greenhouse warning will increase global precipitation (+7to +15%, Table 2.4), the regional impacts are much less certain (-20 to +20%, Table 2.4) ; several s show tendencies for midlatitude continental interiors to experience greater aridity under 2*CO² equilibrum conditions. Because relatively small changes in precipitation and temperature can have large effects on soil moisture status and the volume and timing of runoff, the impacts of climate change on regional water supplies can be large. We expect regional predictions of climayic patterns of air temperature and precipitation to improve as the horizontal resolution of the GCMs increases (i.e. the spatial mesh used for calculations becomes finer), as the simulation of heat uptake and transport by the ocean improves and as the parameterization of modeled clouds improves in all respects. The 2*CO² experiments by the climate-modelling groups must also evolve from their equilibrium calculations for doubled CO² conditions to the modelling of a transient response to increasing atmospheric CO² (Schneider and Thompson 1981). Such models would incorporate a gradual increasing of simulated CO² content, a more realistic method, which becomes important when water resource and other policy decisions are being made. Lastly, because of the interconnectedness of the physical environment and man’s use of physical resources, environmental and social scientists must evaluate the impact of long-term , simultaneously occuring environmental problems. For example Glantz and Ausubel (1984) compare and contrast the implications of existing groundwater mining of the Ogallala aquifer because of agricultural activities in the United States Great Plains with the potential for increased frequency, duration and severity of droughts in the region with global warming. As the ability of the GCMs to make regional-scale predictions of climate patterns improves, further study of long-term slowly developing but cumulative environmental problems that occur will be needed.
Numéro du document :	A/MAC
Niveau Bibliographique :	2
Bull1 (Theme principale) :	METEOROLOGIE ,ATMOSPHERE,CLIMATOLOGIE
Bull2 (Theme secondaire) :	ATMOSPHERE,CLIMATOLOGIE-CONSIDERATION GENERALE

Global climate change and water resources [texte imprimé] / John T. Hayes, Auteur . - Chapman and Hall, 1991 . - p 18-42.
Langues : Anglais (eng)

Catégories :	SCIENCES DE L'ENVIRONNEMENT
Mots-clés :	CHANGEMENT CLIMATIQUE  GENERAL CIRCULATION MODELS (GCM)  EFFET DE SERRE  RESSOURCES D’EAU  HYDROLOGIE
Résumé :	The global rise of atmosphere CO² and other trace gases alter temperature and therefore, precipitation. Together, these change global, as well as regional climates and hydrology. Evapotranspiration, soil moisture content, surface runoff, groundwater recharge, seasonal snowfall, timing of snowmelt periods, river flows, lake levels, hydrologic variability and sensitivity, natural and artificial storage and seal-level rise and associated coastal flooding will all be affected. Although there may be a growing consensus among climate modelers that a greenhouse warning will increase global precipitation (+7to +15%, Table 2.4), the regional impacts are much less certain (-20 to +20%, Table 2.4) ; several s show tendencies for midlatitude continental interiors to experience greater aridity under 2*CO² equilibrum conditions. Because relatively small changes in precipitation and temperature can have large effects on soil moisture status and the volume and timing of runoff, the impacts of climate change on regional water supplies can be large. We expect regional predictions of climayic patterns of air temperature and precipitation to improve as the horizontal resolution of the GCMs increases (i.e. the spatial mesh used for calculations becomes finer), as the simulation of heat uptake and transport by the ocean improves and as the parameterization of modeled clouds improves in all respects. The 2*CO² experiments by the climate-modelling groups must also evolve from their equilibrium calculations for doubled CO² conditions to the modelling of a transient response to increasing atmospheric CO² (Schneider and Thompson 1981). Such models would incorporate a gradual increasing of simulated CO² content, a more realistic method, which becomes important when water resource and other policy decisions are being made. Lastly, because of the interconnectedness of the physical environment and man’s use of physical resources, environmental and social scientists must evaluate the impact of long-term , simultaneously occuring environmental problems. For example Glantz and Ausubel (1984) compare and contrast the implications of existing groundwater mining of the Ogallala aquifer because of agricultural activities in the United States Great Plains with the potential for increased frequency, duration and severity of droughts in the region with global warming. As the ability of the GCMs to make regional-scale predictions of climate patterns improves, further study of long-term slowly developing but cumulative environmental problems that occur will be needed.
Numéro du document :	A/MAC
Niveau Bibliographique :	2
Bull1 (Theme principale) :	METEOROLOGIE ,ATMOSPHERE,CLIMATOLOGIE
Bull2 (Theme secondaire) :	ATMOSPHERE,CLIMATOLOGIE-CONSIDERATION GENERALE