If North Carolina, the United States, or the world plans to take steps to limit global warming, it makes sense to know how much human activity contributes to warming.

Some models suggest humans play a major role, but Duke University research scientist Nicola Scafetta says those models downplay the role of the sun. Scafetta explained his work during a presentation today to the John Locke Foundation’s Shaftesbury Society.

5:15 p.m. update: Watch the entire presentation here.