All life depends on a healthy planet but the interconnected systems of the atmosphere, oceans, streams, land, ice, and biosphere that form the natural environment are threatened by human activities. The Global Atmosphere Watch (GAW) program provides reliable scientific data and information on aerosols, greenhouse gases, selected reactive gases, ozone, ultraviolet radiation, and precipitation chemistry (or atmospheric fallout).
The natural environment suffers, for example, from long-term lack of rainfall and uncontrolled land use which leads to desertification. It is estimated that one third of the Earth's surface and one fifth of the world's population are at risk of desertification. Therefore, the World Meteorological Organization (hereinafter — WMO) turns its attention to aspects of climate variability and change that affect the environment.
Observational data for weather, climate and atmosphere which are collected through WMO observing, data transfer and forecasting networks, inform policymakers about the state of the environment so that they can better prevent further degradation. All these are used by the Intergovernmental Panel on Climate Change (IPCC) in its climate change assessments.