Who started the global warming epidemic and when?

Answer 1

This started in the eighteenth century with the beginning of the Industrial Age, although at first the changes were so slight that scientists were unaware of them.

Around the beginning of the twentieth century, Svante Arrhenius calculated that emissions from human industry might someday bring a global warming, but other scientists dismissed his idea as faulty. In 1938, G.S. Callendar stated that the level of carbon dioxide was climbing and raising global temperature, but most scientists found his conclusions implausible - scientists tend to have a bias against novel theories until the evidence is undeniable. It was only in the early 1960s, when C.D. Keeling measured the level of carbon dioxide in the atmosphere and found that it was rising fast that researchers began to take an interest. We now know that average global temperatures are indeed rising, and that global warming is associated with the increased levels of carbon dioxide produced by human activity.