http://www.livescience.com/43588-volcanoes-global-warming-pause.html
http://www.theatlantic.com/technology/archive/2010/04/could-icelands-volcano-slow-global-warming/39066/
Here is some more on Calbuco. Scientists are saying a third even more powerful eruption may happen.
http://www.cnn.com/2015/04/23/americas/chile-volcano/