Weighing warming.

• Author: Miller, J.M.
• Position: Includes related article - Global warming

These are the facts:

* The chemistry of the atmosphere is changing and a global warming is expected due to the increasing concentrations of greenhouse gases and altered amounts of clouds and particles in the atmosphere.

* The stratospheric ozone layer and, consequently, the surface solar flux of ultraviolet radiation, is being modified.

* The oxidation capacity of the atmosphere is changing.

* Trace gases, including those with significant green-house warming potential, are abundant.

And, to document and understand these global changes, global cooperation is essential.

The chemical composition of the atmosphere is changing, with far reaching implications for the health of the environment and our future. Carbon dioxide and other greenhouse gas concentrations are increasing. The stratospheric ozone layer is being depleted. There is more tropospheric ozone and higher levels of acidity in precipitation. The radiative balance of the Earth-atmosphere-energy system is changing.

All these reflect the increasing influence of human activity on the global atmosphere. And, the responsibility for the long-term monitoring of global atmospheric composition and its related physical characteristics rests with the World Meteorological Organization (WMO), an intergovernmental organization and a specialized agency of the United Nations, through its Global Atmosphere Watch (GAW), established in 1989, with a coordinated network of observing stations, associated facilities and infrastructure encompassing measurement and related scientific activities. These activities, some of which date back to the 1950s, integrate the efforts of several regional and global networks. WMO facilitates and coordinates the monitoring activities and scientific assessments, and oversees the operation of component networks on a continuing basis, rather than being involved in day-to-day network operations. These are the responsibility of the WMO member countries that operate the stations and provide the central facilities such as quality assurance/science activity centres, world calibration centres and world data centres.

This complex task is being tackled by WMO jointly with other international organizations and the scientific community. In collaboration with the United Nations Development Programme, WMO has recently established through the Global Environment Facility six new GAW stations of global importance at pristine locations in Algeria, Argentina, Brazil, China, Indonesia and...