SRI-RTP

Imagine that you had a small cat opening in your front door—big enough for a kitten to get through but not an adult cat. After a while your house would be full of cats, as small ones came in, grew, and couldn’t get out.
Greenhouse gases in the atmosphere are like that cat door: they let in light and heat from the sun; but when the earth tries to send the heat back out in a different form (microwaves, the same kind you heat food with), some of the microwaves can’t get through the greenhouse gases. Greenhouse gases, including carbon dioxide, occur naturally in the atmosphere, and over time the atmosphere has reached an equilibrium temperature. A certain amount of heat escapes through the gases and a steady-state has developed. Luckily for us, the temperature of the atmosphere stays at a comfortable level for human beings.
But the comfortable human beings have been putting more greenhouse gases into the atmosphere since the industrial revolution. As a result, a little bit less of the microwave radiation is escaping and the atmosphere is warming. So far this warming is manageable, but as we continue to burn fossil fuels the threat of major disruptions increases.