PASCO, Wash. -

Researchers are flying over Western wildfires to sample the thick smoke they emit to study its role in cloud formation and climate.

The data-gathering campaign is intended to help researchers flesh out one of the least understood areas of climate: the role of aerosols, or particles given off by wildfires, and how they evolve over time.

So far, the researchers from Brookhaven National Laboratory and Pacific Northwest National Laboratory say they're finding that the white smoke from smoldering fires actually has a cooling effect on the Earth, while the black smoke from a fire that is burning heavily has a warming effect.

However, wildfires also contribute to climate change by releasing large amounts of carbon dioxide and by burning trees that would normally store carbon.