Gardening in the Global Greenhouse: The Impacts of Climate Change on Gardens in the UK

Further copies of this report and the accompanying summary report are available from: iii Preface Preface There are three interrelated phenomena wh i c h need to be identified in reviewing the potential impacts of climate change on gardens. The first is climate change itself. The climatic changes expected in the UK are described in the report Climate Change Scenarios for the United Kingdom: The UKCIP02 Scientific Report (Hulme et al., 2002). This report examines the potential impacts of the expected climate changes on gardens in the UK. The second phenomenon is the occurrence of extreme weather events such as floods and droughts. Climate change is expected to increase the frequency of some extreme weather events, bu t predictions of such events are less certain than those for average changes in climate. Predictions of gale frequency in future are part i c u l a r ly uncertain. The third phenomenon is development. The Earth' s surface has changed dramatically as a result of human activity. Forests have been cleared (in the UK as elsewhere), grasslands have been ploughed and fields covered with houses, factories, motorways and airports. People travel much more widely and much more frequently than was the case even twenty years ago. Some of these changes are root causes of climate change. Others serve to intensify the impacts of climate change or to bring them to wider notice. Covering prev i o u s ly absorbent land surfaces with concrete alters the hydrological balance and exacerbates the severity of floods and droughts caused by extreme weather events. Building houses in floodplains increases the risk and cost of flood damage by orders of magnitude. Moving around the globe results in the spread of pests and diseases, of plants and of humans, to new areas so it is often impossible to say if changes in disease incidence are the results of climate change or of human activity. Much of the information relating to climate change and gardens is anecdotal. In order to draw on well founded scientific research it has been necessary to m ove outside the garden and use data from research on agricultural and horticultural crops, and in forestry and nature conservation. This is logical because the plants grown on farms and in forests, or which are managed in nature reserves, also play an important part in gardens. There are important differences though between monocultur-al stands of …