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EXECUTIVE SUMMARY


Decreased quantities of total-column ozone are now observed over large parts of the globe, permitting increased penetration of solar UV-B radiation (280-315 nm) to the Earth´s surface. The present assessment deals with the possible consequences. The Atmospheric Science Panel predicts that the ozone layer will be in its most vulnerable state during the coming two decades. Some of the effects are expected to occur during most of the next century. Recent studies show that the effects of ozone depletion would have been dramatically worse without the protective measures taken under the Montreal Protocol.

The assessment is given in seven chapters, summarised as follows:

Changes in Ultraviolet Radiation

Effects on Human and Animal Health
- Effects on the immune system will also affect all populations but may be both adverse and beneficial. Adverse effects include depressed resistance to certain tumors and infectious diseases, potential impairment of vaccination responses, and possibly increased severity of some autoimmune and allergic responses. Beneficial effects could include decreases in the severity of certain immunologic diseases/conditions such as psoriasis and nickel allergy.

- Effects on the skin could include increases in photoaging, and skin cancer with risk increasing with fairness of skin. Increases in UV-B are likely to accelerate the rate of photoaging, as well as increase the incidence (and associated mortality) of melanoma and the non-melanoma skin cancer, basal cell and squamous cell carcinoma.
 

  • Research is generating much new information that is being used to help reduce the uncertainties associated with the current risk estimates. Evaluation of the impact of susceptibility genes is helping to identify highly susceptible populations so that their special risk can be assessed. Examination of the impacts of behavior changes such as consuming diets that are high in antioxidants, avoiding sun exposure during the four hours around solar noon, wearing covering apparel, e.g., hats, sunglasses, is beginning to identify important exposure patterns as well as possible mitigation strategies.

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  • Quantitative risk assessments for a variety of other effects, such as UV-B induced immunosuppression of infectious diseases, are not yet possible. New information continues to confirm the reasonableness of these concerns, but data adequate for quantitative risk assessment are not yet available.
  • Effects on Terrestrial Ecosystems Effects on Aquatic Ecosystems Effects on Biogeochemical Cycles Effects on Air Quality Effects on Materials



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