Figure 6-6The Greenhouse Effect (a) Sunlight and heat from Earth’s interior warm Earth’s surface, which in turn radiates energy, mostly as infrared radiation. Much of this radiation is absorbed by atmospheric carbon dioxide and water, heating the air, which in turn increases Earth’s temperature even further. In equilibrium, Earth radiates as much energy as it receives. (b) The amount of carbon dioxide in our atmosphere since 1000 c.e. has been determined. The increase in carbon dioxide since 1800, due to burning fossil fuels and deforestation, has caused a dramatic temperature increase.