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The 'baseline' period is the period of reference from which future climate change projections are calculated. All projections of future climate change in UKCP09 are given relative to the climate average of the baseline period of 1961-1990.

In detail

The baseline or reference climate is conventionally a 30-year average, relating to either climate observations or to model-simulated data. For UKCP09 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.

Find out more

  • More details about the baseline climate of the UK, including regional differences, are given in the Observed trends report.