Key Facts on Atmospheric Issues

• The level of carbon in the atmosphere is increasing. Global average temperatures are increasing. Carbon dioxide (CO2), the predominate "greenhouse gas," is responsible for approximately 60 per cent of the global warming.
  
  
• Six countries, two of which are in the developing world (Brazil and India), are responsible for 55.8 per cent of the total atmospheric impact of current global emissions. The United States is the largest emitter.
  
  
• The stratospheric ozone layer filters dangerous radiation and keeps it below tolerable levels to enable life to exist on Earth. This protective stratospheric ozone layer is diminishing due to chemicals created by humankind.
  
  
• Air pollution does not respect boundaries; it affects agriculture and ecosystems far from its source.
  
  
• More than 600 million people live in urban areas where sulfur dioxide (SO2) levels exceed World Health Organization guidelines. More than 125 million live in cities with unacceptable levels of suspended particulate matter (SPM).
  
  
• For megacities in general, SPM is the single most threatening air pollutant. Particularly high levels of SO2 and SPM occur in five cities: Beijing, Mexico City, Rio de Janeiro, Seoul and Shanghai.
  
  
• Of the cities for which there is sufficient data to compare, Mexico City has the worst overall air pollution.
  
  
• When pollutants are released into the sky from industries, they often fall back to Earth as "acid rain." According to the World Resources Institute, Europe has already lost at least 22 per cent of its total forest cover to acid rain, or a total of 214,016,000 hectares. The United Kingdom alone has damage caused to more than two million hectares, or about 57 per cent of its forest. As unsustainable industrialization spreads around the world, so too could this phenomenon.
  
  

All photos, text and illustrations Copyright ©1996 The United Nations Environment Programme.