Hadley Centre aims: 1. understand physical, chemical and biological processes within the climate system and develop computer models of the climate which represent them; 2. use computer models to simulate the differences between global and regional climates; the changes seen over the last 100 years, and to predict changes over the next 100 years; 3. monitor global and national climate variability and change; 4. attribute recent changes in climate to specific factors. The Hadley Centre undertakes studies of the global climate using similar, though more extensive, models of the atmospheres, as are used for the prediction of weather conditions.