IMPACTS OF CLIMATE CHANGE AND DEVELOPMENT ON WATER RESOURCES AT THE BASIN SCALE
Project rationale and key aims
QUEST-GSI (global-scale impacts of climate change) seeks to better quantify the impacts of climate change in a consistent way across the entire globe, and for a range of sectors including water resources, flooding, crops and human health. The QUEST-GSI research consortium is led by Professor Nigel Arnell of the Walker Institute (University of Reading) and funded by NERC (UK) under the QUEST: Quantifying and Understanding the Earth System programme.
Climate change impact studies on freshwater resources commonly employ a wide range of socio-economic and climate scenarios. Such variability complicates comparisons of the impacts for different socio-economic and climate futures, and prevents a systematic understanding of the effects of proposed policy measures to reduce greenhouse gas emissions. Using a common suite of a climate and socio-economic scenarios, we are working with partner institutions around the world (Table 1) to assess the impacts of climate change and future development on freshwater resources at the basin scale and to quantify uncertainty in these predictions.
Basin-scale water resources
Adaptation to climate change and accelerated development will normally be conducted at the basin scale. Hydrological models at the basin scale allow for more explicit representations of available freshwater resources (e.g. soil water, groundwater) and demand than is permitted by global macro-scale models, and aid the evaluation of freshwater availability predicted by these macro-scale hydrological models. Basin-scale studies also provide an excellent forum to assess indicator metrics of adaptation, risk and vulnerability defined at the global scale.
High-resolution (0.5º x 0.5º) future climate predictions based on a GCM pattern-scaling approach (ClimGen) will be used to drive
basin-scale hydrological models. Drawing from (at least) 7 GCMs in the IPCC 2007 AR4 report (CCCMA, CSIRO, IPSL, ECHAM5, NCAR-CCSM3, HadCM3, HadGEM), we will evaluate uncertainty among GCMs, emissions scenarios (SRES A1b, A2, B1, B2), and prescribed warming (0.5ºC increments in mean global air temperature change from 0.5ºC to 6.0ºC). The latter research is of fundamental importance to policy as it enables a determination of the impact of a given increase in global mean temperature including the so-called 2ºC threshold for 'dangerous climate change'.
Climate and development scenarios will be applied to basin-scale models that cover a broad range of spatial scales and climatic, environmental and developmental conditions (Table 1). Parameter uncertainty in basin-scale hydrological models will be evaluated through the use of ensembles.
Table 1. QUEST-GSI basin-scale studies and collaborators
|River Nile tributary (River Mitano)||Daniel Kingston||UCL|
|River Mekong||Daniel Kingston, Geoff Kite||UCL / Hydro-Logic Solutions|
|River Okavango||Denis Hughes||Rhodes University, South Africa|
|River Changjiang (Yangtze)||Yan Huang, Yang Wenfa||Changjiang Water Resources Commission, China|
|River Parana tributary (Rio Grande)||Walter Collischonn, Marcio Nobrega||Universidade Federal do Rio Grande do Sul, Brazil|
|River Mackenzie tributary (River Liard)||Robin Thorne||McMaster University, Canada|
|River Xiangxi (tributary of River Yangtze)||Hongmei Xu||National Climate Centre, China|
|River Huangfuchuan (tributary of River Yellow)||Hongmei Xu||National Climate Centre, China|