There, the sulfur dioxide produced aerosols that reflected enough sunlight to reduce global temperature by an estimated 0.3 °C for 3 years. (sciencemag.org)
His research suggested that industrial aerosols could block sunlight and reduce global temperatures enough to overcome the effects of greenhouse gases, possibly triggering an ice age. (discovermagazine.com)
Allowing for urban effects reduced the global temperature trend over the period 1900 - 2009 by 0.01 °C. (skepticalscience.com)