by Alan Cheetham
July 28, 2009
SPPI REPRINT SERIES ♦ October 1, 2010
The U.N.-based IPCC (Intergovernmental Panel on Climate Change) produced its latest report in 2007 (AR4). Its position on global warming (based on the outputs of computerized climate models) indicates that the models only depend on anthropogenic CO2 after 1970 – prior to that, warming and cooling is explained by natural factors. So even though industrial civilizations have been producing increased amounts of CO2 since the late 1800s, it only becomes a factor in the models after 1970.