When did global warming start? It could be earlier than we thought. (August 25, 2016)

Gretel Kauffmann writes for The Christian Science Monitor, discussing how scientists have found proof that man-made climate change caused by greenhouse gas emissions can started as far back as the mid-1800s. It was previously tracked back to the late 1800s. Some scientists, including Dr. Michael E. Mann, do not agree with the findings.