Contributed by Robert Lyman © 2021
Definitions: CMIP – Climate Model Intercomparison Project (there are successive stages of these climate models, i.e., CMIP5, CMIP6. Climate ‘models’ are complex computer simulations run on supercomputers to try and evaluate future climate and temperature conditions.)
Fundamentals of climate ‘models’ for lay people: McKitrick on Climate Change- The “Pause” in Global Warming. The Flaws in Climate Models.
The publication of the results from the Intergovernmental Panel on Climate Change (IPCC) CMIP6 climate models in early August was widely publicized as confirming the direst projections of global warming.
(Editor’s note: Climate ‘models’ are computer simulations run on advanced supercomputers to try and simulate/estimate future climate scenarios – see references above. Most of the ‘code red’ media proclamations are related the press release of UN Secretary-General Antonio Guterres – which actually had nothing to do with the content of the report!)
Thousands of articles have since been published touting the CMIP6 model runs as the gold standard in climate science and irrefutable evidence that reducing global greenhouse house emissions is urgent if the world is to be saved.
Except that the models do not reflect reality. Two newly published and peer-reviewed scientific papers by independent teams have confirmed that the IPCC climate models significantly overstate atmospheric warming, and that, even with the issuance of a new set of models with CMIP6, the problem has gotten worse over time, not better.
In this article, I will summarize in layperson’s terms the articles as described by Dr. Ross McKitrick, a principal author of one of the studies. Dr. McKitrick’s paper can be found in its entirety here:
The papers referred to are Mitchell et al. (2020) and “The vertical profile of recent tropical temperature trends: Persistent model biases in the context of internal variability” by Ross McKitrick and John Christy.
Both teams of researchers sought to compare the projections of the CMIP6 models on temperatures in the earth’s atmosphere to the actual changes in temperature over the period since 1979. In other words, both papers looked at “hindcasts”, which are constructions of actual recent historical temperatures in response to observed greenhouse gas emissions and other changes that might affect climate, to see whether they are consistent with what the IPCC models indicate should have occurred. Both groups found that the IPCC models overshoot the historical warming from the near-surface through the upper atmosphere, in the tropics and globally. If the models results have not aligned with reality up to now, what trust can we place in them to be right a century hence?
Overall, the findings of the Mitchell et al. paper were that:
• Based on an examination of the 48 CMIP6 models, they show considerable warming bias in the modeled trends, and these biases are linked to biases in surface temperature.
• For the period from 1998 to 2014, the IPCC’s previous set of CMIP5 models warmed, on average, 4 to 5 times faster than the actual observations.
• Focusing on the CMIP6 models, the modeled tropospheric trends are biased warm throughout the troposphere, and these biases can be linked to biases in surface warming.
• There has been no improvement between the CMIP5 and CMIP6 models.
McKitrick and Christy compared models to observations in the tropical mid-troposphere, also finding a bias in all 38 of the models they examined. They also concluded that the bias is becoming worse in the newer models.
McKitrick could not resist a special mention.
“A special prize goes to the Canadian model! We draw attention to the CanESM5 model: it simulates the greatest warming in the troposphere, roughly 7 times larger than observed trends. The Canadian government relies on the CanESM models ‘to provide science-based quantitative information to inform climate change adaptation and mitigation in Canada and internationally.’ I would be very surprised if the modelers at UVic ever put warning labels on their briefings to policy makers. The sticker should read: WARNING! This model predicts atmospheric warming roughly 7 times larger than observed trends. Use of this model for anything other than entertainment purposes is not recommended.”
The world and the climate policy community in particular are all living with the consequences of climate modelers stubbornly using generation after generation of models that exhibit too much surface and tropospheric warming, in addition to running grossly exaggerated forcing scenarios, such RCP8.5, the scenario that underlies the 2018 report upon which the calls for “net zero” emissions by 2050 are based. The problems with the IPCC models have been known since at least 2005, when they were pointed out in the first report of the US Climate Change Science program. Indeed, the biases that were evident in 2005 have not only continued but extended to analysis of trends throughout the global lower- and mid-troposphere. This marks a consistent bias on the part of the modeling community.
The public and policy makers should not be misled by either the modelers’ bias or the media’s enthusiasm for alarming stories about the global climate. The evidence clearly shows that future warming projections are overstated, as is the need for urgent and economically-destructive government action to reduce the production and use of fossil fuels.
Friends of Science 11th Annual Event – Dr. Ross McKitrick – “The Pause in Global Warming: Climate Policy Implications”
Friends of Science rebuttal to the 2018 IPCC SR1.5 report
McKitrick on Climate Change – series of short videos discussing climate models and their inherent faults.