European droughts under climate change: projections and uncertainties

Droughts are one of the most damaging natural hazards, and anthropogenic climate change has and will continue to alter their characteristics. Better understanding of changes in drought characteristics under potential future climates is vital for managing drought risks and impacts, yet projections are very uncertain. This thesis examines the effects of climate change on European drought characteristics through a multi-scenario and multimodel approach. It explores the uncertainty associated with emission scenarios, global and spatial climate projections, and with the identification and characterisation of droughts. Climate projections simulated by the simple climate model MAGICC6.0 and patternscaling climate scenario generator ClimGen are assessed, emulating eighteen CMIP3 general circulation models (GCMs) under ten emission scenarios. Drought severity (magnitude times duration) and spatial extent are analysed for both 3-month and 12-month events. Drought projections vary substantially depending on the GCM, emission scenario, region, season and definition of drought. Overall, climate change enhances drought conditions across the study region, with marked increases simulated for the southern latitudes; reductions are projected for the northern latitudes, especially in winter and spring. Perturbations in the interannual variability of precipitation tend to enhance drought conditions caused by mean precipitation changes, or to moderate or reverse their reductions. Hydrological drought parameters are highly sensitive to potential evapotranspiration (PET), which shows the importance of the PET calculation method. Greater agreement in the direction of change tends to occur in the high- and low-latitudes, and in summer and autumn. Both meteorological and hydrological drought results generally indicate the same direction of change, with the latter having larger magnitudes. Projection ranges tend to increase with time and magnitude of warming; intra-GCM spread dominates other sources of uncertainty. The implications of the large uncertainties include that decision-making should be based on multi-scenario and multi-model results, and with consideration of drought definition.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of East Anglia

Year dc:date.issued

2013

Author dc:creator

• Yu, Rita Man Sze

Language dc:language

en