MAGICC: Model for the Assessment of Greenhouse-gas Induced Climate Change
MAGICC consists of a suite of coupled gas-cycle, climate and ice-melt models integrated into a single software package. The software allows the user to determine changes in greenhouse-gas concentrations, global-mean surface air temperature, and sea level resulting from anthropogenic emissions of:
- carbon dioxide (CO2)
- methane (CH4)
- nitrous oxide (N2O)
- reactive gases (CO, NOx, VOCs)
- various halocarbons that are not controlled by the Montreal Protocol (HCFCs, HFCs, PFCs and SF6) - Montreal gas emissions changes are hard-wired into the code
- sulfur dioxide (SO2)
The years 1990 and 2100 are the default start and end output years used by the software, but they can be changed by the user.
The main aims of MAGICC are:
- To compare the global-mean temperature and sea level implications of two different emissions scenarios. For convenience, MAGICC refers to these as a "Reference" scenario and a "Policy" scenario. However, any two scenarios may be compared.
- To determine the sensitivity of the temperature and sea level results for any chosen emissions scenario to changes in and uncertainties in model parameters, such as the climate sensitivity. Basic uncertainty ranges and a "best-estimate" result are calculated by default. In addition, the user may select a set of model parameters that differs from the best-estimate set to examine uncertainties associated with model parameter uncertainties in more detail.
SCENGEN: A Regional Climate SCENario GENerator
SCENGEN constructs a range of geographically explicit climate change projections for the globe using the results from MAGICC together with AOGCM climate change information from the CMIP3/AR4 archive. Projections of absolute (rather than relative) future climate conditions for any future date covered by the input emissions data can be obtained also. To produce these projections, SCENGEN adds the climate change information to observed baseline climate data (1980-99 means). These results are given as array files on a standard 2.5x2.5 degree latitude/longitude grid and displayed as maps.
User-choices in the production of such future climate or climate change scenarios are: a future date; a climate variable (temperature, precipitation or MSLP); either a specific month or season or the annual mean; and one or more of the AOGCMs in SCENGEN's library of model results. Climate change fields are constructed using a pattern scaling method.
Beyond simple climate change scenario construction (i.e., changes in the mean climate state), SCENGEN produces spatial pattern results for: changes in inter-annual variability; two different forms of signal-to-noise ratio (to assess the significance of changes); probabilistic output (the default being the probability of an increase in the chosen climate variable); and a wide range of model validation statistics for individual models or combinations of models to assist in the selection of models for scenario development.
This version of MAGICC/SCENGEN was developed primarily with funding from the U.S. Environmental Protection Agency, but it rests on developments carried out over the past 20 years that were funded by a number of organizations.