Following recommendations on operational decadal predictions from the World Climate Research Programme (WCRP) and WMO Technical Commissions, GPCs-ADCP and LC-ADCP were established under the WMO Global Data Processing and Forecasting System by the 69th session of the WMO Executive Council in May 2017. One of the core functions of the LC-ADCP is to coordinate an annual consensus prediction product - Global Annual to Decadal Climate Update (GADCU), in liaison with relevant WCRP activities. giving global prospects for the next 1–5 years. The GADCU provides the international community with a global‐scale expert assessment of latest climate predictions for the next five years set in the context of the recent observed global climate, along with information on robustness of the available forecast signals. The first GADCU was produced in 2020, targeting the 2020-2024 period.
The forecasts presented through the GADCU are intended as guidance for Regional Climate Centres (RCCs), Regional Climate Outlook Forums (RCOFs) and National Meteorological and Hydrological Services (NMHSs). GADCU is also useful for UN agencies and international organizations interested in long-lead predictions of global climate for planning of adaptation and humanitarian assistance. The GADCU is currently guided by the WMO Expert Team on Climate Services Information System Operations (SERCOM) while GPCs and forecast production are guided by the WMO Expert Team on Operational Climate Prediction Systems (INFCOM) using the Global Data-Processing and Forecasting System. Global annual to decadal climate prediction is now well-established and an increasing number of climate services are being developed for these timescales. More information about the GADCU can be found in a free-to-access BAMS article.
