Understanding climate impacts on water resources at both the regional and global scale.
We use climate models, in conjunction with impact models, to make integrated assessments on the effects of climate change and climate variability on water resources. By including important processes such as glaciers, irrigation and interactions with vegetation, we aim to improve the representation of hydrological processes in our models. A key area of our work is understanding the role of historical land-use and climate change on water resource availability. This enables us to make better projections of the impact of future change on water resources. We are working with key government and industries groups to ensure climate change is considered most appropriately in water management.
The Nile River is a crucial freshwater resource for north-eastern Africa. In collaboration with the Egyptian Ministry of Water Resources and Irrigation and DHI Water, Environment and Health, we are assessing the possible impacts of climate change on the Nile river flow and in particular the inflow to the High Aswan Dam.
Within the EU FP7 project HighNoon, we are collaborating with partners from Europe and India to assess the impact of Himalayan glaciers retreat, and possible changes of the Indian summer monsoon on the spatial and temporal distribution of water resources in Northern India. A glacier model is being developed for inclusion in the Met Office Climate Model, as well as a water resources model to route runoff through the river network.
Irrigation is often seen as an adaptation strategy for regions projected to have an increasing level of water stress. As part of the EU FP6 Water and Global Change project (WATCH) we have been working on including irrigation in the Met Office Regional Climate Model to help evaluate the demand for irrigation water in Northern India against available sustainable resources.
As part of the EC-funded programmes ENSEMBLES and WATCH the land surface model Joint UK Land Environment Simulator (JULES) is being validated with regard to the simulation of the hydrology and river discharge in major river basins around the world. JULES simulates the interactions between soil moisture, rivers and vegetation, so allows for a more complete, full-system view of climate change impacts. For example, the direct impacts of carbon dioxide on vegetation have important knock-on effects on the water cycle.
Improving the representation of river flows in our climate models is an ongoing development. This is important for a number of reasons, changes in freshwater discharge may not only have a major effect on society, but may also exert an influence on the ocean circulation. River discharge is also a useful quantity for validating the hydrological aspects of large-scale models, as it integrates the water balance across a very wide area. The TRIP river routing scheme (Oki, 1998) has been implemented in the HadGEM2 Earth System Model and the simulated runoff is being validated with observed river discharge.