Climate change is arguably the most important environmental problem facing the world’s population. In 1988, the Intergovernmental Panel on Climate Change (IPCC) was established through a resolution of the United Nations General Assembly

with concern that the emerging evidence indicates that continued growth in atmospheric concentrations of ‘greenhouse’ gases could produce global warming with an eventual rise in sea levels, the effects of which could be disastrous for mankind if timely steps are not taken at all levels (United Nations General Assembly, 1988).

The IPCC has since helped create a collective knowledge of climate change that shapes public policy for sustainable development and raises awareness of the threats to human security posed by a changing climate and, therefore, the need for action to avoid such threats in the future. The IPCC 4th Assessment ‘Scientific Basis’ report (IPCC, 2007b) describes some key features of the many climate models in use around the world, along with themain uncertainties and improvements that are beingmade. In the UK,much of the climate change information used for impacts studies derives frommodels developed at the Met Office Hadley Centre, which have been summarised by Pope et al. (2007).

19.1.1 Assessment of global climate change