CMIP5

CMIP5
Name	CMIP5
Full name	Coupled Model Intercomparison Project Phase 5
Started	2008
Coordinated by	World Climate Research Programme
Participants	Intergovernmental Panel on Climate Change, Met Office Hadley Centre, National Center for Atmospheric Research, NASA Goddard Institute for Space Studies
Purpose	Multi-model climate experiments for Assessment Reports

CMIP5 The Coupled Model Intercomparison Project Phase 5 provided a coordinated framework for climate model experiments used in the Intergovernmental Panel on Climate Change Fifth Assessment Report. It brought together modeling centers such as the Met Office Hadley Centre, National Center for Atmospheric Research, NASA Goddard Institute for Space Studies, Canadian Centre for Climate Modelling and Analysis, Max Planck Institute for Meteorology, and Institut Pierre-Simon Laplace to compare coupled atmosphere–ocean simulations across standardized protocols. CMIP5 produced multi-model ensembles that supported research at institutions including European Centre for Medium-Range Weather Forecasts and Lawrence Livermore National Laboratory and informed assessments by agencies like National Oceanic and Atmospheric Administration and UK Met Office.

Overview

CMIP5 was coordinated by the World Climate Research Programme and organized under working groups tied to the Intergovernmental Panel on Climate Change cycle, with governance involving the Global Climate Observing System, Climate Variability and Predictability project, and the International Geosphere-Biosphere Programme. It specified experiment protocols, data standards, and metadata conventions influenced by initiatives such as the Earth System Grid Federation and the Program for Climate Model Diagnosis and Intercomparison. Major model development contributions came from centers including GFDL, CSIRO, Météo-France, NOAA Geophysical Fluid Dynamics Laboratory, Scripps Institution of Oceanography, and Potsdam Institute for Climate Impact Research.

Models and Experiments

Models participating in CMIP5 included atmosphere-only models from European Centre for Medium-Range Weather Forecasts and coupled Earth system models from Max Planck Institute for Meteorology, Geophysical Fluid Dynamics Laboratory, Hadley Centre, GISS, CCCma, CSIRO Mk3, and IPSL-CM. Experiments followed standardized runs: historical simulations, pre-industrial control runs, 1% per year CO2 increase experiments, and abrupt CO2 quadrupling experiments used by groups such as Princeton University climate scientists and researchers at University of Reading and Columbia University. Idealized experiments and decadal prediction hindcasts integrated methodologies developed at NOAA and ECMWF and were used to diagnose processes studied in publications from Nature Geoscience, Journal of Climate, and Geophysical Research Letters.

Forcing Scenarios and Representative Concentration Pathways

CMIP5 adopted Representative Concentration Pathways (RCPs) like RCP2.6, RCP4.5, RCP6.0, and RCP8.5 developed by multidisciplinary teams including contributors from IIASA, Potsdam Institute for Climate Impact Research, and International Institute for Applied Systems Analysis. RCPs linked emissions pathways to radiative forcing trajectories used in impact studies by groups at Stanford University, Harvard University, Princeton and policy assessments by the Intergovernmental Panel on Climate Change. Forcing datasets encompassed greenhouse gases, aerosols, land-use change from initiatives such as the Land-Use Harmonization Project, solar irradiance reconstructions from NOAA, and volcanic forcing records compiled by researchers at University of Bristol and Laboratoire de Météorologie Dynamique.

Data Access and Processing

CMIP5 data were distributed through the Earth System Grid Federation nodes hosted by LLNL, PCMDI, ESGF, and centers like CEDA and DODS. Data formats and conventions followed CF metadata conventions and NetCDF standards used at UCAR and NOAA. Processing pipelines employed tools from PCMDI Metrics Package, ESGF Data Node, xarray development led by teams at University of California, Riverside and University of Washington, and visualization platforms like Panoply and NCL used by researchers at Lamont-Doherty Earth Observatory and Scripps Institution of Oceanography.

Evaluation and Performance

Model evaluation leveraged observational datasets from HadCRUT4, GISTEMP, ERA-Interim, NOAA NCEI, CRU TS, and satellite records from NASA Aqua, NOAA GOES, ERS-2, and TOPEX/Poseidon. Skill assessment used metrics developed at PCMDI, statistical frameworks from IPCC Working Group I authors, and emergent constraints methodologies advanced by scientists at University of Alaska Fairbanks and Columbia University. Performance diagnostics addressed biases in tropical variability, Atlantic Meridional Overturning Circulation modeled by GFDL and MPI, and cloud feedback differences highlighted by studies in Journal of Climate and Nature involving researchers from LLNL and Met Office.

Applications and Impacts

CMIP5 ensembles informed impact assessments performed by IPCC AR5 authors and national agencies such as US EPA and DEFRA. The dataset underpinned regional downscaling studies by groups at CORDEX, adaptation planning in municipalities like New York City and London, and sectoral analyses in agriculture by FAO and water resources studies at World Bank. CMIP5 outputs supported detection and attribution studies cited by National Research Council reports, influenced mitigation scenario modeling at ICAP, and fed integrated assessment models developed at IIASA and MIT.

Legacy and Successor Projects

CMIP5 established protocols that guided CMIP6 with participation from ESGF and lessons carried into initiatives such as CORDEX, Coupled Model Intercomparison Project Phase 6, and the Scenario Model Intercomparison Project. Data stewardship practices influenced repositories like PANGAEA and data citation practices advocated by International Science Council and DataCite. Many modeling centers that contributed to CMIP5—GFDL, Hadley Centre, MPI-M, IPSL, NOAA labs, and university groups—continued model development in successor experiments and multimodel intercomparisons used by the Intergovernmental Panel on Climate Change.

Category:Climate modeling