The extent to which they affect radiation also depends on the time of day. As the diagram shows, when the Sun is high in the sky its radiation travels a shorter distance through the atmosphere than it does when it is low, and consequently it encounters and reacts with a smaller number of aerosol particles.
Scientists still have much to learn about the way aerosols affect radiation and, through that, the climate. In its 2001 scientific report, the Intergovernmental Panel on Climate Change (IPCC) estimated the present effects of five types of aerosol: sulfate; unburned hydrocarbons from fossil fuels; black smoke; particles from forest, bush, grass, and other vegetation fires; and gases and ash ejected during volcanic eruptions. The IPCC concludes that all of these have an overall cooling effect on climate, with the exception of black smoke, which has a warming effect. It is a small effect, however, ranging from a warming effect of about 0.2 watts per square meter (W m-2) for black smoke to a cooling effect of up to about 1.0 W m-2.
Was this article helpful?
Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.