Visit following link..
http://en.wikipedia.org/wiki/Global_warming
Neither is particularly useful.
Global warming is heating of earth. It causes ozone depletion.
If we understand the causes and effects of global warming then we can change our behaviour to reduce these effects. We can also talk to our friends and family so that more people can spread the message to change our behaviour.
Ozone depletion causes global warming. This then causes global temperature to change.
There are several thesis statements one could make about global warming and its effects in the world. For example: Global warming is resulting in more frequent and more severe weather events.
Ozone depletion causes global warming. Global warming causes floods.
Pollution causes global warming. This global warming causes ozone depletion.
There are many effects. Global warming is a example.
global warming
Global Warming
Global Warming
Pollution causes global warming. This global warming causes ozone depletion.