Follow Us

WCRP Coupled Model Intercomparison Project (CMIP)

The objective of the Coupled Model Intercomparison Project (CMIP) is to better understand past, present and future climate changes arising from natural, unforced variability or in response to changes in radiative forcing in a multi-model context. This understanding includes assessments of model performance during the historical period and quantifications of the causes of the spread in future projections. Idealized experiments are also used to increase understanding of the model responses. In addition to these long time scale responses, experiments are performed to investigate the predictability of the climate system on various time and space scales as well as making predictions from observed climate states. An important goal of CMIP is to make the multi-model output publically available in a standardized format.

CMIP began in 1995 under the auspices of the Working Group on Coupled Modelling (WGCM). The first set of common experiments involved comparing the model response to an idealized forcing - a constant rate of increase which was accomplished using a CO2 increase of 1% per year compounded. Since that time a number of CMIP experiments have been developed. The experiments continue to include integrations using idealized forcings to facilitate understanding. They now also include integrations forced with estimates of the changes in the historical radiative forcings as well as estimates of the future changes.

In addition to the major experiments, CMIP has also included a series of smaller model intercomparison efforts, called the Coordinated CMIP Experiments, designed to understand specific aspects of the model response. One experiment investigated the Atlantic Meridional Overturning Circulation (AMOC), or thermohaline circulation (THC) response to changes in the surface fluxes of heat and water. Another Coordinated Experiment documented the model response to external surface water flux in high latitudes of the North Atlantic, the so-called "water hosing experiments". A number of papers have been written using these datasets.

read more

CMIP Panel

CMIP activities are overseen by the CMIP Panel which is a standing subcommittee of the WGCM. It is the responsibility of the CMIP Panel to follow the guidance of the WGCM committee. The CMIP Panel oversees the design of the various CMIP experiments, oversees the various CMIP datasets and to helps resolve problems that arise either during the model integrations/data generation phase or in the use of the datasets. The WGCM committee has the ultimate responsibility to oversee the whole CMIP process.

CMIP panel members
V. Eyring (Chair) DLR, Germany
G. Meehl NCAR, USA
B. Stevens MPI-M, Germany
R. Stouffer NOAA/GFDL, USA
K. Taylor PCMDI, USA

Send queries by email to V. Eyring (please use subject: "CMIP Panel question")