The authors compared, for the overlapping time frame 1962-2000, "the estimate of the northern hemisphere mid-latitude winter atmospheric variability within the available 20th century simulations of 19 global climate models included in the Intergovernmental Panel on Climate Change [IPCC] 4th Assessment Report" with "the NCEP-NCAR and ECMWF reanalyses," i.e., compilations of real-world observations produced by the National Center for Environmental Prediction (NCEP), in collaboration with the National Center for Atmospheric Research (NCAR), and by the European Center for Mid-Range Weather Forecast (ECMWF)....And this:
Quoting...the scientists who performed the model tests, "this study suggests caveats with respect to the ability of most of the presently available climate models in representing the statistical properties of the global scale atmospheric dynamics of the present [our italics] climate and, a fortiori ["all the more," as per Webster's Dictionary], in the perspective of modeling [future] climate change." Indeed, it gives one pause to question most everything the models might suggest about the future.
It is difficult to understand how scientific forecasting could be conducted without reference to the research literature on how to make forecasts. One would expect to see empirical justification for the forecasting methods that were used. To provide forecasts of climate change that are useful for policy-making, one would need to prepare forecasts of (1) temperature changes, (2) the effects of any temperature changes, and (3) the effects of feasible proposed policy changes. To justify policy changes based on climate change, policy makers need scientific forecasts for all three forecasting problems and they need those forecasts to show net benefits flowing from proposed policies. If governments implement policy changes without such justification, they are likely to cause harm to many people....P.S. See also this post at World Climate Report.
Based on our literature searches, those forecasting long-term climate change have no apparent knowledge of evidence-based forecasting methods....
Related post: "Warmism": The Myth of Anthropogenic Global Warming