Global Mean Temperature Change (deltaT)

The deltaT value shown in the SCENGEN Menu bar is the annual global-mean surface air temperature warming in degrees Celsius for the 30-year Interval selected and for the emissions Scenario selected. This global warming is expressed relative to the period or year shown in the wrt box. These values have been calculated by MAGICC and are thus dependent on the parameter selection made by the user within MAGICC. Within SCENGEN, the Clim Sen and MAGICC Parameters selections control the combination of MAGICC parameters for which the global warming value is shown.

IMPORTANT: The warming value shown will always be for greenhouse-gas-only forced climate change unless the user selects an aerosol GCM change pattern from the GCMs sub-menu.

If an aerosol pattern is selected on its own then the deltaT value will be the MAGICC-generated global warming/cooling for the chosen scenario and parameter selection. If both greenhouse gas and aerosol GCM patterns of change are chosen then the deltaT shown will be the net global temperature change resulting from both greenhouse gas and aerosol forcing.