AccuWeather.com's Evan Myers interviewed the Penn State climate scientist about his views on human-induced global warming, as well as his degree of certainty on his research.

Michael Mann has called himself a "reluctant and accidental public figure" in the global debate over climate change. Interested in "big-picture science," the researcher started studying changing climate at Yale in the early '90s. Mann's research attracted the public eye when his team published the infamous "hockey stick graph," showing a rapid increase in global warming in the 20th century.