The term 'decadal prediction' encompasses predictions on annual, multi-annual to decadal timescales. The potential to make skillful forecasts on these timescales, and the ability to do so, is investigated by means of predictability studies and retrospective forecasts (termed hindcasts) using climate models and statistical approaches. Predictability and prediction studies have focused largely on temperature, and there is evidence of skill in the prediction of variations in annual means of temperature over much of the globe for several years, conditional on the initialization of the forecasts. As the forecast range increases initialized skill decreases but some skill is maintained due to external forcing from greenhouse gases, aerosols and volcanoes. There is currently less skill in predicting precipitation and other variables compared to temperature although progress is expected to be made as a consequence of the Decadal Climate Prediction Project (DCPP) and other projects and investigations.
The coordination of the scientific and practical aspects of decadal climate prediction research within WCRP is undertaken by the DCPP Panel under the guidance of the Working Group on Subseasonal to Interdecadal Prediction (WGSIP). The DCPP is organized into three components:
- Component A, Hindcasts: the design and organization of a coordinated decadal prediction (hindcast) experiment, in conjunction with the seasonal prediction and climate modelling communities, and the production of a comprehensive archive of results for research and applications
- Component B, Forecasts: the ongoing production of experimental quasi-operational decadal climate predictions in support of multi-model annual to decadal forecasting and the application of the forecasts to societal needs
- Component C, Predictability, mechanisms, and case studies: the organization and coordination of decadal climate predictability studies and of case studies of particular climate shifts and variations, including the study of the mechanisms that determine these behaviours
Groups are invited to participate in as many or as few of the DCPP experiments as are of interest to them.
The results of the DCPP are a contribution to the 6th Coupled Model Intercomparison Project (CMIP6), to the WCRP Grand Challenge on Near Term Climate Prediction (NTCP), potentially to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), to the Global Framework for Climate Services (GFCS), and as one of the bases for the development of a WMO Commission for Basic Systems (CBS) Global Decadal Climate Outlook (GDCO) in support of applications.
NOTE: In 2017 the Working Group on Seasonal to Interannual Prediction (WGSIP) changed its name to the Working Group on Subseasonal to Interdecadal Prediction (WGSIP). Where you see the older name used, it is to preserve the name as used in pre-2017 projects.