Thousands of 13th-Century Londoners May Have Been Killed By A Distant Volcano
http://blogs.discovermagazine.com/80beats/2012/08/09/thousands-of-13th-century-londoners-may-have-been-killed-by-a-distant-volcano/
The Mysterious Missing Eruption of 1258 A.D.
http://www.wired.com/wiredscience/2012/02/the-mysterious-missing-eruption-of-1258-a-d/
Graph of global temperatures:
http://www.wired.com/images_blogs/wiredscience/2012/02/MFRFigu2d.jpg