The Power of Independent Thinking


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Research Article

Why Models Run Hot
Results from an Irreducibly Simple Climate Model

An irreducibly simple climate-sensitivity model is designed to empower even non-specialists to research the question how much global warming we may cause. In 1990, the First Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) expressed “substantial confidence” that near-term global warming would occur twice as fast as subsequent observation. Given rising CO2 concentration, few models predicted no warming since 2001. Between the pre-final and published drafts of the Fifth Assessment Report, IPCC cut its near-term warming projection substantially, substituting “expert assessment” for models’ near-term predictions. Yet its long-range predictions remain unaltered. The model indicates that IPCC’s reduction of the feedback sum from 1.9 to 1.5 W m−2 K−1 mandates a reduction from 3.2 to 2.2 K in its central climate-sensitivity estimate; that, since feedbacks are likely to be net-negative, a better estimate is 1.0 K; that there is no unrealized global warming in the pipeline; that global warming this century will be <1 K; and that combustion of all recoverable fossil fuels will cause <2.2 K global warming to equilibrium. Resolving the discrepancies between the methodology adopted by IPCC in its Fourth and Fifth Assessment Reports that are highlighted in the present paper is vital. Once those discrepancies are taken into account, the impact of anthropogenic global warming over the next century, and even as far as equilibrium many millennia hence, may be no more than one-third to one-half of IPCC’s current projections.

David R. Legates is an Associate Professor and Director of the Center for Climatic Research at the University of Delaware and a Research Fellow at The Independent Institute in Oakland, Calif. He is also co-author of the Independent Institute monograph, New Perspectives in Climate Change: What the EPA Isn't Telling Us.

William M. Briggs has served as Professor of Statistics at the Cornell University Medical School, Visiting Professor of Mathematics at Central Michigan University, Research Scientist at New York Methodist Hospital, Statistician at DoubleClick, Meteorologist with the National Weather Service, and Cryptologist for the U.S. Air Force.

Christopher Monckton is the 3rd Viscount Monckton of Brenchley in the United Kingdom. He was Special Advisor to British Prime Minister Margaret Thatcher from 1982 to 1986, and he has served as Secretary for the Centre for Policy Studies's economic, forward strategy, health and employment study groups; Deputy Leader of the UK Independence Party (UKIP); and the UKIP's President in Scotland.

Wei-Hock "Willie" Soon is a solar astrophysicist at the Harvard-Smithsonian Center for Astrophysics.