Local and regional climates over time have shaped and determined landform and natural envir on ments, such as slope angles, soils and natural habitats. Climate has also helped determine our built envir on ments (though the strength of this influence is changing): for instance, the angles of roofs, and the ratio of window to wall, have been influenced in the past by local climatic norms for rainfall intensity and temperature. We experience the climate of a location every day as weather, which includes temperature, rainfall and snow, frost, sunshine hours, cloud cover and wind speed. Climate change leads to changes in all of these in terms of absolute levels experienced and their frequency, intensity or length (e.g. of storms, droughts or heatwaves). Climate change is also resulting in rises in sea level. The process of warming of the low-level atmosphere – which evidence suggests has been particularly marked since about 1950 (IPCC 2007b) – gives rise to impacts across the range of economic sectors, envir on ments and systems (physical, human and biological). The extent of change and impacts experienced will depend upon other factors including geographical location (e.g. altitude, latitude, distance from coasts), the nature of the local envir on ment and the extent to which it is already under pressure from human populations.