The natural greenhouse effect keeps some of the sun’s heat on earth. Without the natural greenhouse effect, the temperature would be much colder than it is. Carbon dioxide is the most important greenhouse gas. There is a natural, healthy level of carbon dioxide in our air so that plants, animals, and humans can live. The problem is that too much carbon dioxide traps too much heat in the air. Because of carbon pollution, the amount of heat in the atmosphere is increasing, which is making our climate change.
This picture shows what experts say would happen if the world were to get warmer. Sea ice and glaciers would melt. Oceans would get warmer. Sea levels would rise. Air temperatures would get warmer and air would hold more water vapor. Weather stations around the US and around the world found that every one of these things has happened. These indicators all show that our climate is changing – the world is getting warmer.