what is global warming?
Global warming is when the earth heats up (the temperature rises). It happens when greenhouse gases (carbon dioxide, water vapor, nitrous oxide, and methane) trap heat and light from the sun in the earth’s atmosphere, which increases the temperature. This hurts many people, animals, and plants. Many cannot take the change, so they die.
Url:
http://library.thinkquest.org/CR0215471/global_warming.htm
What are the causes?
1) Pollution from factories
2) Carbon dioxide from rotting trees
3) The burning of coal
URL:
http://www.macgregoss.eq.edu.au/qldwebchall/gwi/causes.html

What are the effects?
1) Rising sea level
2) increase in the frequency of some extreme weather events
3) Forest fires
Url: http://en.wikipedia.org/wiki/Effects_of_global_warming