WMO Climatology Commission Calls for More Frequent Climate Baselines

WMO9 July 2014: The World Meteorological Organization (WMO) Commission for Climatology convened to adopt a 2014-2018 work plan aimed at accelerating national efforts to deliver and use climate services, and address issues such as data management, climate prediction and capacity building. The Commission also recommended that governments adopt a two-tier approach to updating the 30-year baselines used by scientists and meteorological services to monitor the weather and climate, and make comparisons with past conditions.

Climatologists use 30-year averages, called “climate normals,” of temperatures, precipitation and other variables to put into historical context, for example, the magnitude of a current heatwave or rainstorm, since the climate naturally varies from year to year. While the current official period is 1961-1990 as updates occur once every 30 years, rising atmospheric greenhouse gas (GHG) concentrations are changing the climate more quickly leading to the potential for decision making based on out-of-date information. Thus, many weather services have begun using the period 1981-2010: to provide a more recent context for understanding weather and climate extremes and forecasts; and for other operational services, such as forecasts of peak energy load and recommendations on crop selection and planting times. However, using different baselines results in inconsistent comparisons.

During its 16th session, held from 3-8 July 2014, in Heidelberg, Germany, the Commission for Climatology: recommended adopting a new global standard for decadal updates, while maintaining the 1961-1990 period for monitoring long-term climate variability and change; and proposed that all countries begin using the period 1981-2010 for most purposes and updating this period every ten years. The proposed technical regulation on 'Calculating Climatological Standard Normals Every 10 Years' will be forwarded to the WMO's governing body, the World Meteorological Congress, for consideration and adoption at its next meeting, scheduled to take place from 25 May-12 June 2015.

Other issues discussed during the meeting included future priorities and progress made on such initiatives as: centennial observing stations' efforts to build a long-term climate observation record; and facilitating the real-time international exchange of multi-annual to decadal climate predictions. The Commission also proposed activities, such as: ensuring advances in collecting, archiving, reanalyzing and managing climate data; expanding efforts to rescue international climate data; providing further guidance on methodologies and standards for climate monitoring and assessment; improving the user interface for climate adaptation and risk management; and implementing quality management systems.

The meeting was preceded by the three-day WMO Technical Conference on Climate Services: Building on the Climate Information and Prediction Services (CLIPS) Legacy, which explored how the outputs of the 20-year CLIPS project, which concludes in 2015, will transition into the Global Framework for Climate Services (GFCS). The WMO Commission for Climatology promotes international cooperation in climatology and the use of climate information and knowledge for supporting sustainable development, environmental protection and operational climate services. [WMO Press Release, 3 July 2014] [WMO Press Release, 9 July 2014]