ISSUES AND CONCERNS ABOUT GLOBAL ATMOSPHERIC OZONE

The ozone in the global troposphere and stratosphere plays several imp ortant roles in affecting humanity and other living organisms on Earth . Ozone is important as an absorber of solar ultraviolet radiation, pr eventing biologically harmful levels of ultraviolet (UV) radiation fro m reaching the Earth's surface. Ozone is also a greenhouse gas and its global distribution plays an important role in determining the Earth' s climate. In recent years, it has become progressively clearer that h uman activities may be affecting the amount of ozone in the global atm osphere. Atmospheric measurements now indicate that the amount of ozon e in the stratosphere is decreasing, while the amount of ozone in the global troposphere, the atmosphere below about 10 km altitude, appears to be increasing. Overall, the vertically integrated amount of ozone, referred to as the total ozone column, is decreasing. Understanding t he changes occurring to ozone and determining the appropriate societal response present important challenges to scientists and to policymake rs. In,this paper, we review the current scientific understanding of g lobal atmospheric ozone and the changes occurring in its distribution. We also examine the response that governments are making to the chang es occurring in ozone.