Online climate change projections report 4.4.7 PDFs & future climate
Users have the choice of seeing projections of some variables as climate change or as future climate. Climate change is that between the chosen time period and the 1961–1990 baseline 30-year period. Therefore, we calculate projections of future change from model simulations by subtracting the simulated baseline period from the simulated future values. This reduces the impact of model bias on the projected change, though of course it does not guarantee that the projected change will be correct. Projections of absolute values for future climate variables are then obtained by adding the projected changes onto the observed baseline value.
Figure 4.26 shows a PDF of the change in summer-mean daily maximum temperature, for a 25 km square in the East of England, by the 2080s under the High emissions scenario. In Figure 4.27, this change has been added to the 1961–1990 observed summer-mean daily maximum temperature, to give a projection of the summer-mean daily maximum temperature for the 2080s. Note that the two PDFs have the same shape, but the future climate PDF in Figure 4.27 is shifted by about 20ºC relative to the climate change PDF in Figure 4.26 — where 20ºC represents the baseline summer-mean daily maximum temperature at that location.
| Figure 4.26: A PDF of the change in summer-mean daily maximum temperature, for a 25km square in the East of England, by the 2080s under the High emissions scenario. | ||
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| Figure 4.27: A PDF of the projected future summer-mean daily maximum temperature, for a 25 km square in the East of England, by the 2080s under the High emissions scenario. | ||
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- Last updated: Sunday, 11 March 2012