- The Parties to the Convention recognize that the major scientific issues are:
- Modification of the ozone layer which would result in a change in the amount of solar ultra-violet radiation having biological effects (UV-B) that reaches the Earths surface and the potential consequences for human health, for organisms, ecosystems and materials useful to mankind;
- Modification of the vertical distribution of ozone, which could change the temperature structure of the atmosphere and the potential consequences for weather and climate.
- The Parties to the Convention, in accordance with article 3, shall co-operate in conducting research and systematic observations and in formulating recommendations for future research and observation in such areas as:
- Research into the physics and chemistry of the atmosphere
- Comprehensive theoretical models: further development of models which consider the interaction between radiative, dynamic and chemical processes; studies of the simultaneous effects of various man-made and naturally occurring species upon atmospheric ozone; interpretation of satellite and non-satellite measurement data sets; evaluation of trends in atmospheric and geophysical parameters, and the development of methods for attributing changes in these parameters to specific causes;
- Laboratory studies of: rate coefficients, absorption cross-sections and mechanisms of tropospheric and stratospheric chemical and photochemical processes; spectroscopic data to support field measurements in all relevant spectral regions;
- Field measurements: the concentration and fluxes of key source gases of both natural and anthropogenic origin; atmospheric dynamics studies; simultaneous measurements of photochemically-related species down to the planetary boundary layer, using in situ and remote sensing instruments; intercomparison of different sensors, including co-ordinated correlative measures for satellite instrumentation; three-dimensional fields of key atmospheric trace constituents, solar spectral flux and meteorological parameters;
- Instrument development, including satellite and non-satellite sensors for atmospheric trace constituents, solar flux and meteorological parameters;
- Research into health, biological and photodegradation effects
- The relationship between human exposure to visible and ultra-violet solar radiation and (a) the development of both non-melanoma and melanoma skin cancer and (b) the effects on the immunological system;
- Effects of UV-B radiation, including the wavelength dependence, upon (a) agricultural crops, forests and other terrestrial ecosystems and (b) the aquatic food web and fisheries, as well as possible inhibition of oxygen production by marine phytoplankton;
- The mechanisms by which UV-B radiation acts on biological materials, species and ecosystems, including: the relationship between dose, dose rate, and response; photorepair, adaptation, and protection;
- Studies of biological action spectra and the spectral response using polychromatic radiation in order to include possible interactions of the various wavelength regions;
- The influence of UV-B radiation on: the sensitivities and activities of biological species important to the biospheric balance; primary processes such as photosynthesis and biosynthesis;
- The influence of UV-B radiation on the photodegradation of pollutants, agricultural chemicals and other materials;
- Research on effects on climate
- Theoretical and observational studies of the radiative effects of ozone and other trace species and the impact on climate parameters, such as land and ocean surface temperatures, precipitation patterns, the exchange between the troposphere and stratosphere;
- The investigation of the effects of such climate impacts on various aspects of human activity;
- Systematic observation on:
- The status of the ozone layer (i.e. the spatial and temporal variability of the total column content and vertical distribution) by making the Global Ozone Observing System, based on the integration of satellite and ground-based systems, fully operational;
- The tropospheric and stratospheric concentrations of source gases for the HOx, NOx, ClOx and carbon families;
- The temperature from the ground to the mesosphere, utilizing both ground-based and satellite systems;
- Wavelength-resolved solar flux reaching, and thermal radiation leaving, the Earths atmosphere, utilizing satellite measurements;
- Wavelength-resolved solar flux reaching the Earths surface in the ultra-violet range having biological effects (UV-B);
- Aerosol properties and distribution from the ground to the mesosphere, utilizing ground-based, airborne and satellite systems;
- Climatically important variables by the maintenance of programmes of high-quality meteorological surface measurements;
- Trace species, temperatures, solar flux and aerosols utilizing improved methods for analyzing global data.
- The Parties to the Convention shall co-operate, taking into account the particular needs of the developing countries, in promoting the appropriate scientific and technical training required to participate in the research and systematic observations outlined in this annex. Particular emphasis should be given to the intercalibration of observational instrumentation and methods with a view to generating comparable or standardized scientific data sets.
- The following chemical substances of natural and anthropogenic origin, not listed in order of priority, are thought to have the potential to modify the chemical and physical properties of the ozone layer.
- Carbon substances
- Carbon monoxide (CO)
Carbon monoxide has significant natural and anthropogenic sources, and is thought to play a major direct role in tropospheric photochemistry, and an indirect role in stratospheric photochemistry.
- Carbon dioxide (CO2)
Carbon dioxide has significant natural and anthropogenic sources, and affects stratospheric ozone by influencing the thermal structure of the atmosphere.
- Methane (CH4)
Methane has both natural and anthropogenic sources, and affects both tropospheric and stratospheric ozone.
- Non-methane hydrocarbon species
Non-methane hydrocarbon species, which consist of a large number of chemical substances, have both natural and anthropogenic sources, and play a direct role in tropospheric photochemistry and an indirect role in stratospheric photochemistry.
- Nitrogen substances
- Nitrous oxide (N2O)
The dominant sources of N2O are natural, but anthropogenic contributions are becoming increasingly important. Nitrous oxide is the primary source of stratospheric NOx, which play a vital role in controlling the abundance of stratospheric ozone.
- Nitrogen oxides (NOx)
Ground-level sources of NOx play a major direct role only in tropospheric photochemical processes and an indirect role in stratosphere photochemistry, whereas injection of NOx close to the tropopause may lead directly to a change in upper tropospheric and stratospheric ozone.
- Chlorine substances
- Fully halogenated alkanes, e.g. CCl4, CFCl3 (CFC11), CF2Cl2 (CFC12), C2F3Cl3 (CFC113), C2F4Cl2 (CFC114)
Fully halogenated alkanes are anthropogenic and act as a source of ClOx which plays a vital role in ozone photochemistry, especially in the 3050 km altitude region.
- Partially halogenated alkanes, e.g. CH3Cl, CHF2Cl (CFC22), CH3CCl3, CHFCl2 (CFC21)
The sources of CH3Cl are natural, whereas the other partially halogenated alkanes mentioned above are anthropogenic in origin. These gases also act as a source of stratospheric ClOx.
- Bromine substances
Fully halogenated alkanes, e.g. CF3Br
These gases are anthropogenic and act as a source of BrOx, which behaves in a manner similar to ClOx.
- Hydrogen substances
- Hydrogen (H2)
Hydrogen, the source of which is natural and anthropogenic, plays a minor role in stratospheric photochemistry.
- Water (H2O)
Water, the source of which is natural, plays a vital role in both tropospheric and stratospheric photochemistry. Local sources of water vapor in the stratosphere include the oxidation of methane and, to a lesser extent, of hydrogen.