The Albrecht effect describes how
cloud condensation nuclei
Cloud condensation nuclei (CCNs), also known as cloud seeds, are small particles typically 0.2 µm, or one hundredth the size of a cloud droplet. CCNs are a unique subset of aerosols in the atmosphere on which water vapour condenses. This c ...
(CCN), possibly from anthropogenic pollution, may increase cloud lifetime and hence increase the amount of solar radiation reflected from clouds. Because it does not directly interact with incoming or outgoing radiation, it has an indirect effect on climate.
Aerosol particles act as CCNs creating more droplets of a smaller size. These take more time to coalesce to raindrop size reducing precipitation efficiency and hence increasing the lifetime of the cloud. The increased scattering of incoming radiation leads to a cooling of −0.3 to
[IPCC 4th Assessment Report, 2005] This effect is not as well understood as the
Twomey effect
The Twomey effect describes how additional cloud condensation nuclei (CCN), possibly from anthropogenic pollution, may increase the amount of solar radiation reflected by clouds. This is an indirect effect (or radiative forcing) by such particles, ...
.
There are many other effects, indirect and semi-direct aerosol effects resulting in a large uncertainty in the radiative forcing due to aerosols.
See also
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Particulates and soot
References
Bibliography
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Particulates
Clouds
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