Do you wonder why 2015 was the hottest year since thermometers were invented? It turns out that global warming is caused by ozone depletion, not greenhouse gases. In August 2014, Bárðarbunga in central Iceland began erupting basaltic lava flows that in six months covered an area of 33 square miles, the size of Manhattan, the highest rate of such lava extrusion since 1783, a major event. Chlorine and bromine from such lava depletes the ozone layer, allowing more ultraviolet-B solar radiation to reach Earth. This video is an introduction by Dr. Peter L. Ward to the website https://WhyClimateChanges.com that explains the science in detail.