Any policy to reduce heat-trapping pollution will inevitably target the main sources of Americans' energy: the coal burned by power plants for electricity and the oil that is refined to run automobiles.

NPR: PROMISES, PROMISES: Climate Change

Such a change in temperature -- which many scientists believe is being caused by pollution trapping heat in the atmosphere -- would mean widespread droughts and floods and massive economic and natural damage, experts say.

CNN: Climate talks secure U.S. support

We are constantly innovating, figuring out new more efficient ways to remove heat from machines while reducing pollution.

FORBES: Google as a New Innovation Model (Or Not the 20% Time)

So the heat and humidity, the pollution all combined as one.

NPR: Beijing Air Quality to Challenge Olympic Athletes

It's also more likely that high pollution levels will occur because heat creates the conditions for photochemical smog.

CNN: In-Depth Specials - City Limits