Most insights come as a surprise: a burst of understanding, an elegant solution to a problem. This decade's main insight in climate science was a different breed. For 40 years, researchers had wrestled with three big questions: Is the world warming? If so, are humans behind the warming? And are natural processes likely to rein it in? In the past few years, climate scientists finally agreed on solid answers: yes, yes, and no—just as they had suspected.

http://www.sciencemag.org/content/330/6011/1623.summary