Guardian: One of the most important concepts to understand when trying to grasp how the Earth's climate works, is that every climate change must have a physical cause. This principle was the basis of our new paper, Nuccitelli et al. (2013). Over the past century, climate scientists have developed a solid understanding about how the climate works and the physical mechanisms that cause it to change. By building that knowledge into complex climate models, scientists have been able to accurately reproduce past...