Global Climate Observing System

GCOS works towards a world where climate observations are accurate and sustained, and access to climate data is free and open.

The Global Climate Observing System (GCOS) is a co-sponsored programme which regularly assesses the status of global climate observations and produces guidance for its improvement.  

It is co-sponsored by the

  • World Meteorological Organization (WMO),

  • Intergovernmental Oceanographic Commission of UNESCO (IOC-UNESCO),

  • United Nations Environment Programme (UN Environment), and

  • International Science Council (ISC).

GCOS expert panels maintain definitions of Essential Climate Variables (ECVs). They identify gaps by comparing the existing climate observation system with these ECVs. ECVs are the observations required to systematically observe Earth`s changing climate. The expert panels regularly develop plans on how to sustain, coordinate and improve physical, chemical and biological observations.

The observations supported by GCOS contribute to solving challenges in climate research and also underpin climate services and adaptation measures.

Visit the GCOS website on