The baseline (or reference) period defines the climatology against which future changes are projected.
The baseline or reference climate is conventionally a 30-year average, relating to either climate observations or to model-simulated data. For UKCP09, and following consultation with the Users’ Panel, the period 1961–1990 was selected as the baseline climate, meaning that all projections of future climate change are given relative to the modelled climate during this period. UKCP09 also provides absolute projections of future climate, derived by adding the climate change projections to an observed 1961–1990 baseline climate.
- More details about the baseline climate of the UK, including regional differences, are given in the UKCP09 Observed trends report.
Find out more