In a remarkable monograph, Roy W. Spencer presents hard evidence that 75% of the observed warming since the start of the 20th century is due to natural processes. He offers a detailed model describing how one of these processes, the Pacific Decadal Oscillation (PDO), operates in the real world. Most importantly, he demonstrates that anthropogenic global warming (AGW) is a minor contributor to a global climate largely insensitive to man-made CO2.................
The most prominent frauds active in promoting AGW have always tried to bury evidence of natural warming and cooling cycles. Truly, the Medieval Warming Period and Little Ice Age are threats to their very CO2-obsessed existence. But these eras occurred centuries ago, with only proxies (like tree rings) to indicate the actual prevailing temperatures. Hence, data from these eras are easily brushed aside and forgotten. Not so with recent thermometer measurements, and temperatures from two periods in particular that have always plagued the theory of AGW.
The first is the period from 1900-1940. A full 60% of the temperature increase measured in the last century occurred during these forty years, when less industrialization existed worldwide and therefore less CO2 had been spewed into our atmosphere. The mild cooling period that ended in the mid-1970s is also baffling. But like any good theory, Spencer's PDO-focused model fits the temperature data during these decades amazingly well. Natural processes -- cloud formation and heat transfer -- dominated the temperatures during these decades, as in every other decade in the modern era.