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Climate Watch and Alert Systems

Hurricane Katrina and Sea Surface Temperatures. Image: NASA

Hurricane Katrina and Sea Surface
   Temperatures. (Image: NASA)

Climate variations and change can affect global and regional atmospheric and oceanic circulations. Significant variations and change, where the system deviates dramatically from the mean state of the climate, are correlated to extreme weather and climate events on various time scales including, monthly, seasonal and annual time scales. Such events can lead directly or indirectly to negative consequences on lives, goods, properties, and the well being of societies. Droughts, heat waves, cold waves, flooding, extreme wind storms, land slides, bush and forest fires, costal erosions and tropical cyclones (like the one pictured) are some of the impacts that can be triggered by variations and changes in circulation.

Many of these variations are actually recurrent and associated with well known climatic patterns such as the El Niño Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), warming/cooling of Sea Surface Temperatures (SST) in the tropical oceans, strengthening/weakening of the upper level Jets, etc.  This means that many of the extreme weather and climate events can, to a certain extent be predicted, and therefore prepared for.

For more than a decade, the WMO and National Meteorological and Hydrological Services (NMHSs) have focused on setting up an effective Climate Watch System to improve the risk management capabilities of nations facing climate extremes.

In the context of global warming these extremes are expected to become more frequent, more severe and gain more geographical extend than currently known. This understanding creates even more need and urgency for a Climate Watch System.

WMO Climate Watch Systems are designed to provide advice and statements to inform their users, particularly those involved in natural hazards preparedness, mitigation and response, about evolving or foreseen climate anomalies at the regional and national levels, thus allowing them to make informed decisions. To this effect, NMHSs should be adequately equipped and prepared to continuously monitor and assess the state of the climate, evaluate available long range forecasts, and where conditions warrant, provide to the users concise and understandable climate early warning information at weekly, 10-day, monthly, and seasonal time scales.

[Further information] about the WMO Climate Watch System can be found on the World Climate Data and Monitoring Programme (WCDMP) programme website.

[More in depth information] about Climate watches can be found in the Brochure Guidelines on Climate Watches



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