Global Warming Scientists say the temperature of the earth could rise by 3C 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 begins to melt and sea levels rise. Global warming is caused by the greenhouse effect. Normally, heat from the sun warms the earth and then comes back into space. But carbon dioxide (углекислый газ) and other gases in the atmosphere catch the sun's heat, and this is slowly making the earth warmer.