Recent climate variability and future climate change scenarios for Great Britain

This article reviews recent climatically extreme periods in Great Britain and presents results from the latest general circulation model (GCM) experiments showing the possible spatial patterns and magnitude of future climate change for this region. During the last decade the British Isles has seen record-breaking periods of above-average temperatures, alongside periods with above and below-average precipitation, combined with an increase in winter precipitation and a decrease in summer precipitation. The impacts of these anomalies, coupled with the possibility that future climate change may increase their frequency and/or severity, have prompted the UK Department of the Environment, Transport and Regions and other organizations involved in environmental management, such as the Environment Agency, to commission a number of studies into their impacts. These have highlighted wide-ranging impacts on the natural environment of Great Britain and on human activities to the extent of affecting the national economy. The use of GCMs for the development of future climate change scenarios is reviewed. Results from recent ensemble GCM experiments with and without the effects of sulphate aerosols are presented. These show broadly similar changes in temperature and precipitation to previous climate change scenarios prepared for Great Britain. In summary, the scenarios suggest the following: a warming of about 3 degrees C (3.5 degrees C) over the region by 2100 with (without) the effects of sulphate aerosols; slight increases in annual precipitation over northern England and Scotland, more pronounced increases over the whole of the region in winter; and slight decreases in precipitation over Wales and central England in summer. These changes are synchronous with decreases in the number of wet-days and increases in the intensity of precipitation on wet-daps. The high level of uncertainty associated with regional scenarios of temperature and precipitation is discussed and emphasized.