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QUEST-GSI Global-Scale Impacts

Impacts of climate change and development on water resources in a global basin network

Project rationale and key aims

QUEST-GSI (global-scale impacts of climate change) operated from 2007 to 2010 and sought to better quantify the impacts of climate change on water resources in a consistent manner across the entire globe by applying an ensemble of innovative climate projections (ClimGen) to using calibrated basin-scale models.  The analysis led by UCL was part of a wider assessment beyond water resources including floods, crop production, and human health that was led by Professor Nigel Arnell of the Walker Institute (University of Reading) and funded by Natural Environment Research Council (UKRI ref. NE/E001890/1) 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, the UCL team led by Taylor collaborated with partner institutions around the world 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 occur at basin scales. Calibrated, basin-scale hydrological models (Table 1) 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) were used to drive basin-scale hydrological models. Drawing from 7 selected GCMs in the IPCC 2007 AR4 report (CCCMA, CSIRO, IPSL, ECHAM5, NCAR-CCSM3, HadCM3, HadGEM), we evaluated 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 outcomes of this research feature centrally in the 5th Assessment Report of the Inter-Governmental Panel on Climate Change, Working Group II, Chapter 3 Freshwater Resources (Figure 3-5) (.pdf) and were published as a series of papers in a special issue of the EGU open-access journal, Hydrology and Earth System Science.

Table 1. QUEST-GSI basin-scale studies and collaborators

BasinCollaboratorInstitution
River Nile tributary (River Mitano)Daniel KingstonUCL
River MekongDaniel Kingston, Geoff KiteUCL / Hydro-Logic Solutions
River OkavangoDenis HughesRhodes University, South Africa
River Changjiang (Yangtze)Yan Huang, Yang WenfaChangjiang Water Resources Commission, China
River Parana tributary (Rio Grande)Walter Collischonn, Marcio NobregaUniversidade Federal do Rio Grande do Sul, Brazil
River Mackenzie tributary (River Liard)Robin ThorneMcMaster University, Canada
River Xiangxi (tributary of River Yangtze)Hongmei XuNational Climate Centre, China
River Huangfuchuan (tributary of River Yellow)Hongmei XuNational Climate Centre, China