Background and History
Background and History
Monitoring of trace atmospheric constituents was originally driven by scientific curiosity. It was not long, however, before questions were raised as to what the consequences would be for humanity should the observed increases in certain trace chemicals continue unabated. The development of major international activities concerned with protection of the environment started in earnest during 1968 when the United Nations was called upon to organise a world conference on internationally significant problems related to the human environment. The conference took place in Stockholm in 1972 and successfully drew world-wide attention to environmental problems, including changes in the atmosphere due to rapid industrialisation.
During the 1970s three important atmospheric issues were addressed: (a) the threat of CFC's to the ozone layer, (b) acidification of lakes and forests in large parts of North America and Europe, caused principally by the conversion of sulphur dioxide into sulphuric acid by precipitation processes in the atmosphere and, (c) potential global warming caused by the build-up of greenhouse gases in the atmosphere. Each of these issues is now the subject of international treaties or conventions. The initial development of these agreements and the subsequent assessments of the mitigation measures they contain, rely heavily on the information derived from WMO's atmospheric composition monitoring programme.
The WMO formally embarked on a programme of atmospheric chemistry and meteorological aspects of air pollution during the 1950s. This included assuming responsibility for standard procedures for uniform ozone observations and establishing the Global Ozone Observing System (GO3OS) during the 1957 International Geophysical Year. In the late 1960s, the Background Air Pollution Monitoring Network was established which was subsequently consolidated with the Global Ozone Observing System into the current WMO Global Atmosphere Watch (GAW) in 1989. The GAW monitoring programme includes a co-ordinated global network of observing stations along with supporting facilities. GAW provides data for scientific assessments and for early warnings of changes in the chemical composition and related physical characteristics of the atmosphere that may have adverse affects upon our environment. Monitoring priorities have been given to greenhouse gases for possible climate change, ozone and ultraviolet radiation for both climate and biological concerns, and certain reactive gases and the chemistry of precipitation for a multitude of roles in pollution chemistry.
The GAW programme has matured considerably during the last few years, and presently consists of many co-ordinated components that have been designed to provide accessible, high quality atmospheric data to the scientific community. These components include: (a) measurement stations, (b) calibration and data quality centres, (c) data centres and, (d) external scientific groups for programme guidance. Support for these components is provided, in large part, by individual WMO Member countries that directly participate in the GAW programme, augmented by some outside international funding, and the WMO Secretariat's internal budget.
The GAW programme is guided by a plan that is detailed in the WMO/GAW Report #142: "Strategy for implementation of the Global Atmosphere Watch Programme (2001-2007)" released in April. This report includes 8 strategic goals:
- Improve measurements programme for better geographical and temporal coverage and for near real time monitoring capability,
- Complete the quality assurance/quality control system,
- Improve availability of data and promote their use,
- Improve communication and co-operation between all GAW components and with the scientific community,
- Identify and clarify changing roles of GAW components,
- Maintain present and solicit new support and collaborations for the GAW programme,
- Intensify capacity building in developing countries,
- Enhance the capabilities of NMHSs in providing urban-environmental air quality services.
Over the lifetime of this Strategic Plan, human activities will continue to change the composition of the atmosphere, although efforts will be made to control them. The WMO GAW network of stations must continue to monitor the critical atmospheric parameters and provide scientific data needed to understand and ultimately predict environmental changes on both regional and global scales.