Environment — Healthy planet
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.
WMO is recognized as a comprehensive source of unique global systematic observations of a wide range of geophysical phenomena, datasets, and long-term archives, as well as scientific and technical knowledge to support policy advice on various critical environmental issues.

Biodiversity (the diversity of life on Earth and the natural forms it makes) helps keep the global environment healthy. Polluted air, depleted or polluted water, degraded soil and urban sprawl are all threats to biodiversity. Rising ocean temperatures are causing widespread bleaching in coral reefs which support huge populations of marine life and are also important tourist attractions. Ecosystems such as wetlands, forests and lakes are an important part of the natural regime of the river. They act as a buffer between river and terrestrial ecosystems and play an important role in the accumulation or reduction of flood waters. Stratospheric ozone protects plants, marine life, animals and humans from the sun's ultraviolet radiation which is harmful to life on Earth. Chlorofluorocarbons and other man-made chemicals are responsible for the ozone depletion. Therefore, it is imperative to ensure that all of these Earth systems remain healthy.
A critical activity of National Meteorological and Hydrological Services is monitoring long-term changes in atmospheric greenhouse gases, ultraviolet radiation, aerosols and ozone and assessing their subsequent impacts on people, climate, air and water quality, also marine and terrestrial ecosystems. Another important activity is monitoring the atmospheric and water transport of hazardous particles following a volcanic explosion or industrial accident.