is perhaps the most important environmental problem in the world today. Levels of greenhouse gases are increasing in the atmosphere due to human activities, and are changing the composition of the atmosphere and global warming. Climate scientists agree that human activities such as the burning of fossil fuels contribute to the problem.
Scientists have predicted the phenomemon of global warming for decades. Unfortunately, some of the adverse effects of global warming, they have also predicted begin to occur throughout the world, including:

• growing incidence of droughts in some areas, floods in others
• The rising temperatures of oceans and the sea level
• increase extreme weather events such as tornadoes and hurricanes
• The melting of mountain glaciers and the reduction of snow cover
• Dying coral reefs, and
• Coastal erosion, and loss of coastal ecosystems.
  

from : www.effectofglobalwarming.com