What are global climate projections?

Global climate projections are climate model simulations which have been generated by multiple independent climate research centres in an effort coordinated by the World Climate Research Program (WCRP) and assessed by the Intergovernmental Panel on Climate Change (IPCC). These climate projections underpin the conclusion of the IPCC 5th Assessment Report that “Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems”. 

This catalogue entry provides daily and monthly global climate projections data from a large number of experiments, models and time periods computed in the framework of the sixth phase of the Coupled Model Intercomparison Project (CMIP6).

CMIP6 data underpins the Intergovernmental Panel on Climate Change 6th Assessment Report. The use of these data is mostly aimed at:

• addressing outstanding scientific questions that arose as part of the IPCC reporting process;
• improving the understanding of the climate system;
• providing estimates of future climate change and related uncertainties;
• providing input data for the adaptation to the climate change;
• examining climate predictability and exploring the ability of models to predict climate on decadal time scales;

The Climate Model Intercomparison Project (CMIP)

The Climate Model Intercomparison Project (CMIP) was established in 1995 by the World Climate Research Program (WCRP) to provide climate scientists with a database of coupled Global Circulation Model (GCM) simulations.

The CMIP process involves institutions (such as national meteorological centres or research institutes) from around the world running their climate models with an agreed set of input parameters. The modelling centres produce a set of standardised output, when combined these produce a multi-model dataset that can be shared internationally between modelling centres and the results compared. 

Analysis of the CMIP data allows for improving understanding of

• the climate, including its variability and change, 
• the societal and environmental implications of climate change in terms of impacts, adaptation and vulnerability,
• informing the Intergovernmental Panel on Climate Change (IPCC) reports. 

• evaluating how realistic the different models are in simulating the recent past

• .

CMIP5

The fifth phase of Coupled Model Intercomparison Project (CMIP5, 2008-2012) involved 24 modelling centres running their climate models under the prescribed conditions to produce the multi-model dataset designed to advance our knowledge of climate (Taylor et al. 2012). The scientific analyses from CMIP5 were used extensively in the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (IPCC AR5), published in September 2013. 

The CMIP5 data archive is distributed through the Earth System Grid Federation (ESGF) though many national centres have either a full or partial copy of the data for their scientists to utilise. A quality-controlled subset of CMIP5 data are made available through the Climate Data Store (CDS) for the users of the Copernicus Climate Change Service (C3S).

To obtain full details of the whole CMIP5 data archive please refer to the full documentation at the Program for Climate Model Diagnosis & Intercomparison (PCMDI). An introductory factsheet for an overview of an IPCC subset also provides a useful guide to the CMIP5 data. 

The term "experiments" refers to the three main categories of CMIP6 simulations:

• Historical experiments which cover the period where modern climate observations exist. These experiments show how the GCMs performs for the past climate and can be used as a reference period for comparison with scenario runs for the future. The period covered is typically 1850-2005.
• Climate projection experiments following the combined pathways of Shared Socioeconomic Pathway (SSP) and Representative Concentration Pathway (RCP). The SSP scenarios provide different pathways of the future climate forcing. The period covered is typically 2006-2100, some extended RCP experimental data is available from 2100-2300.

This catalogue entry provides both two- and three-dimensional data, along with an option to apply spatial and/or temporal subsetting to data requests. This is a new feature of the global climate projection dataset, which relies on compute processes run simultaneously in the ESGF nodes, where the data are originally located.

The data are produced by the participating institutes of the CMIP6 project.

CMIP6