Using Large Climate Ensembles to Plan for the Hydrological Impact of Climate Change in the Freshwater Environment
Water Resources Management
Tyndall Centre for Climate Change Research, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford, OX1 3QY, United Kingdom; Environment Agency of England and Wales, Horizon House, Deanery Road, Bristol, BS1 5AH, United Kingdom; Grantham Research Institute, London School of Economics and Political Sciences, Houghton Street, London, WC2A 2AE, United Kingdom; Department of Environmental and Geographic Science, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa; African Climate and Development Initiative, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
We explore the use of large ensembles of climate scenarios to inform climate change adaptation in response to hydrological impacts on the freshwater environment, using a sensitive chalk river in south east England to illustrate the approach. The climateprediction. net experiment provides large ensembles of transient climate series from 1920 to 2080. We use 246 transient climate series in the CATCHMOD rainfall-run-off model to develop large ensembles of plausible river flows for the River Itchen. This transient ensemble allows the exploration of how flows may change through the twenty-first century, and demonstrates the range of possible consequences for freshwater ecosystems, based on invertebrate community impacts. Hydrological modelling of flow sequences including abstraction allows the continued effectiveness of river support from groundwater to be assessed. A new environmental impact matrix considers the response of the freshwater ecosystem in the Itchen, concentrating particularly on macro-invertebrates. Through the century increasing numbers of models fail the flow targets, with a minority of models suggesting flows that would lead to irreversible change to the invertebrate community. The large ensemble provides a richer picture of the range of possible change, allowing managers to explore a range of different responses. The approach used is illustrative, but demonstrates that large ensembles may be of great value in improving the understanding of the possible impact of climate change, provided that they can be communicated effectively to decision-makers. © 2012 Springer Science+Business Media B.V.
Climate change adaptation; Climate scenarios; Decision makers; England; Freshwater ecosystem; Freshwater environments; Hydrological impacts; Hydrological modelling; Invertebrate communities; Irreversible changes; Large ensembles; Macroinvertebrates; River ecosystem; River flow; Uncertainty; Climate change; Decision making; Ecosystems; Environmental impact; Groundwater; Models; Rivers; Uncertainty analysis; Water resources; Climate models; climate change; climate effect; climate prediction; decision making; ensemble forecasting; environmental impact; freshwater environment; hydrological modeling; macroinvertebrate; rainfall-runoff modeling; river flow; river system; uncertainty analysis; England; Hampshire; Itchen River; United Kingdom; Invertebrata