what is the cause of global warming ???

It is a heat issue.From my own perspective,it is because too much cars,too much air-conditioners, too much gas realse which lead to the growing warmth of our earth.And also the quality of our environment is becoming worse and worse,too much houses,too much population,less trees,less plants. Let's be an environmentalist. Take care.

scientists have determined that a number of human activities are contributing to global warming by adding excessive amount of greenhouse gases to the atmosphere. green house gases like carbon dioxide accumulate in the atmosphere and trap heat that normally would exit in to outer space.

Try Wikipedia. Increase in the amount of greenhouse gases like carbon dioxide and carbon monoxide causes global warming. When fossil fuels like petrol, gasoline, diesel are burnt, carbon dioxide releases. The property of co2 is greenhouse effect, ie, it prevents the heat reflected by the earth from going back into space and traps it closer to the earth itself so temperature rises. This is called global warming and it can melt polar icecaps and cause a lot other problems.

i had a report like this before. try the national geographic online. my report was focused on CO2 as a major cause of global warming and its detailed chemical mechanism on why it destroys the ozone layer and why it causes global warming. I have a copy of the magazine, but i think it might also be available online.