7.3 Running the models forward
What happens when the models are run forward? It depends upon the models used and the scenarios they are asked to run. It seems almost certain, however, that there will be increases in the global mean surface temperature, to the order of +1.5 to +4.5 °C (– possibly more, according to some models and scenarios.
These changes are predicted to be associated with increases in sea level, changes to weather conditions (e.g. more regular and violent winter storms in the UK) and changes to the distribution of habitats and their associated organisms.
The current predictions for the global climate in the twenty-first century are shown for a range of scenarios and models in the charts below. (Chart (a) shows the range of scenarios for CO 2 emissions; charts (b) and (c) show the corresponding predictions for temperature change and rise in sea level.