SOURCE : http://www.skepticalscience.com/global-cooling-mid-20th-century-advanced.htm
This source seems to make a reasonable point about the direct and indirect effects of aerosol's on our atmosphere, but I cannot be a good judge of reliability unless I hear many others saying the same thing. It mentions that the release of sulfates into the atmosphere during that period is most likely the cause of the cooling effect, being the largest period in which they were released into the atmosphere. This article is only about 3 and 1/2 years old, which can have changes in a period like that. One thing that stands out to me is that we see a similar plateau after 1998 when there was an agreement to stop releasing these greenhouse gases into the atmosphere. The effect seems to be similar, but the causes are very different, one period a massive increase in sulfates and aerosols and the other an attempt to phase out and decrease all pollutants and greenhouse gases.
