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This figure shows a graph of global mean temperature predictions are simulated by the climate change model. The x-axis represents the global mean temperature in degree Celsius (10–22°C) and the y-axis represents different phases of the climate change simulation: the first third representing the calibration phase; the second third representing the control phase; and the final third representing the ‘double CO2’ phase. The legend at the bottom of the graph shows the density of temperature predictions in each phase: green areas representing less than 1.5% of predictions, purple areas representing between 1.5% and 4.5% of predictions, and red areas representing more than 4.5% of predictions. The graph shows that the red areas are restricted to between 13°C and 14°C in the calibration phase, and there is limited blue and green colouring on either side of the red. In the control phase, the red area shows a similar distribution, although there is a marked increase in green colouring between 10°C and 13°C. However, in the double CO2 phase, the red areas show a marked increase towards 16°C, but the high variety of results indicate a wide spread of probabilities, with the green areas ranging from 10°C all the way up to 22°C.

 Reading 5.3: Freedom from our mental limitations: simulation models