On April 22 (Earth Day) of 1998, my co-authors and I published the now famous “hockey stick” curve. It was featured on the pages of the New York Times and other leading newspapers, helping it garner worldwide attention.
Here was a simple graph, derived from sources of “proxy” climate data such as tree rings, ice cores, coral, and lake sediment, depicting the average temperature of the northern hemisphere over the past six centuries.
