Human activities have little to do with the Earth's current warming trend, according to a study published by the National Center for Policy Analysis (NCPA). In fact, S. Fred Singer (University of Virginia) and Dennis Avery (Hudson Institute) conclude that global warming and cooling seem to be part of a 1,500-year cycle of moderate temperature swings. Scientists got the first unequivocal evidence of a continuing moderate natural climate cycle in the 1980s, when Willi Dansgaard of Denmark and Hans Oeschger of Switzerland first saw two mile-long ice cores from Greenland representing 250,000 years of Earth's frozen, layered climate history. From...