The Global Atmosphere Watch (GAW) Programme of WMO focuses on building a single coordinated global understanding of atmospheric composition, its change, and helps to improve the understanding of interactions between the atmosphere, the oceans and the biosphere. It coordinates high-quality atmospheric composition observations across global to local scales to drive high-quality and impact science while co-producing a new generation of research enabled products and services. About 100 countries are participating in the GAW Programme. Some components of the GAW observational network are recognised as comprehensive and baseline networks of the Global Climate Observing System (GCOS). The GAW Programme operates according to the GAW Implementation Plan 2024-2027.

One major aspect of the GAW mission is to organise, participate in and coordinate assessments of the chemical composition of the atmosphere on a global scale. In this way, GAW provides reliable scientific information for policymakers, supports international conventions and contributes to improve the understanding of climate change and long-range transboundary air pollution.