Some people say the earth is getting warmer.
They blame something called greenhouse gasses.
The greenhouse gasses destroy the higher atmosphere that keeps our planet from getting too hot.
CFCs are the gasses that cause one of the biggest problems in global warming.
CFCs destroy some of the ozone that is in the higher atmosphere.
The ozone layer helps us by filter out some of the harmful ultraviolet rays from the sun.
These rays can cause skin cancer in humans.
These rays can also help to heat up our planet.
Over the polar ice caps, we now have holes in the ozone layer.
These, people believe, contribute to world’s global warming.
One of its effects could have is to speed up the melting of the polar ice caps.
If these melt too quickly, the level of the sea will rise too fast for us to control it.
The effect of a rise in the height of the sea will be dramatic.
Many of the world’s major cities will be under sea water.
So, global warming can be very dangerous to our future environment.