The evidence for natural causes of global warming, and cooling, far outweighs the empirical evidence for human CO2-induced warming - a remote Andes mountain region lake confirms an excessive natural warming of the climate during the Medieval Period
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Read here. The IPCC continues to proclaim that modern warming (okay, the IPCC does concede that the "warming" has disappeared over last 15 years) is "unprecedented." This proclamation is made based on the UN's political agenda and not the actual empirical research and evidence.
A plethora of peer reviewed studies provide absolute confirmation that prior periods were indeed warmer than our modern era; that both warming and cooling affected the entire globe and not just the European/North Atlantic region; and, that the significant prior climate change was entirely natural, not from human CO2 emissions.
A new study by scientists Fletcher and Moreno provides proof from the Southern Hemisphere that natural global warming is a powerful climatic force that is empirically irrefutable.
"The authors did an analysis of pollen and charcoal from Laguna San Pedro, a small closed-basin lake located in the Andes of Chile. Their results reveal centennial-scale changes in vegetation, climate and fire regime since 1500 cal yr before present...According to the study’s abstract, they found periods of relatively low summer moisture and increased fire activity between 1500–1300 and 1000–725 cal yr BP. The period 1000–725 cal yr BP (i.e. Medieval Warm Period) is characterised by remarkably rapid bulk sediment accumulation, from which they infer prolonged annual sedimentation resulting from a decrease in the duration of lake freezing under a warmer climate. Before the Medieval Warm Period, i.e. 1300–1000, they found relatively moist conditions during summer and low fire activity. After the Medieval Warm Period, from 725–121 cal yr BP, there was slow bulk sediment accumulation implying a cool and wet climate." [Michael-Shawn Fletcher, Patricio Iván Moreno 2012: Quaternary Science Reviews]
Conclusions: Natural causes of global warming and cooling are well documented, not only by anecdotal evidence, but from global empirical research of peer reviewed studies, including evidence from the Southern Hemisphere. It is a scientific travesty that the IPCC rejects the findings of the vast majority of peer reviewed research and instead relies on a handful discredited hockey-stick papers that use the same proxies over and over, and then employ absurd statistical tecniques that can't withstand professional scrutiny. By denying the natural Medieval Warming, the IPCC clearly establishes that the UN political agenda supercedes the actual science.
Previous climate-history and peer-reviewed postings. Historical temperature charts.