Nature, Not Human Activity, Rules the Climate - Science ...

Nature, Not Human Activity, Rules the ClimateSummary for Policymakers of the Report of theNongovernmental International Panel on Climate Change1. IntroductionThe Fourth Assessment Report of theIntergovernmental Panel on Climate Change’sWorking Group-1 (Science) (IPCC-AR4 2007),released in 2007, is a major research effort by agroup of dedicated specialists in many topics relatedto climate change. It forms a valuable compendiumof the current state of the science, enhanced byhaving an index, which had been lacking inprevious IPCC reports. AR4 also permits access tothe numerous critical comments submitted by expertreviewers, another first for the IPCC.While AR4 is an impressive document, it is farfrom being a reliable reference work on some of themost important aspects of climate change scienceand policy. It is marred by errors and misstatements,ignores scientific data that were available but wereinconsistent with the authors’ pre-conceivedconclusions, and has already been contradicted inimportant parts by research published since May2006, the IPCC’s cut-off date.In general, the IPCC fails to consider importantscientific issues, several of which would upset itsmajor conclusion – that “most of the observedincrease in global average temperatures since themid-20th century is very likely (defined by the IPCCas between 90 to 99 percent certain) due to theobserved increase in anthropogenic greenhouse gasconcentrations” (emphasis in the original).The IPCC does not apply generally acceptedmethodologies to determine what fraction of currentwarming is natural, or how much is caused by therise in greenhouse (GH) gases. A comparison of‘fingerprints’ from best available observations withthe results of state-of-the-art GH models leads to theconclusion that the (human-caused) GH contributionis minor. This fingerprint evidence, thoughavailable, was ignored by the IPCC.The IPCC continues to undervalue theoverwhelming evidence that, on decadal andcentury-long time scales, the Sun and associatedatmospheric cloud effects are responsible for muchof past climate change. It is therefore highly likelythat the Sun is also a major cause of twentiethcenturywarming, with anthropogenic GH gasesmaking only a minor contribution. In addition, theIPCC ignores, or addresses imperfectly, otherscience issues that call for discussion andexplanation.The present report by the NongovernmentalInternational Panel on Climate Change (NIPCC)focuses on two major issues:! The very weak evidence that the causes of thecurrent warming are anthropogenic (Section 2)! The far more robust evidence that the causes ofthe current warming are natural (Section 3).We then addresses a series of less crucial topics:! Computer models are unreliable guides to futureclimate conditions (Section 4)! Sea-level rise is not significantly affected byrise in GH gases (Section 5)! The data on ocean heat content have beenmisused to suggest anthropogenic warming. Therole of GH gases in the reported rise in oceantemperature is largely unknown (Section 6)! Understanding of the atmospheric carbondioxide budget is incomplete (Section 7)1