Scientists say the temperature of the earth could rise by 3 c over the next 50 years. This may cause drought in some parts of the world, and floods in others, as ice at the North and South Poles being to melt and sea level rise.
Global warming is caused by the greenhouse effect. Normally, heat from the sun warms the earth and then escapes back into space. But carbon dioxide and other gases in the atmosphere trap the sun's heat, and this is slowly making the earth warmer.