In a new report, the National Academy of Sciences endorses “extreme event attribution (EEA), a field of climate science that analyzes whether and to what extent human-caused climate change influenced an individual extreme weather or climate event.” This endorsement is based upon purported “expanded observational datasets, large-ensemble simulations, and methodological advancements over the past decade…”This is balderdash, as the NAS itself concluded (p. 29) in 2016: “Event attribution questions are often posed in terms of a specific actual event, but definitive attribution of a specific event in a deterministic manner is generally not possible.” Have matters changed much in terms of climate predictions over the last decade? No, they have not: The climate models used by the Intergovernmental Panel on Climate Change were no better in 2021 than in 2014: They continue to overpredict atmospheric temperature trends by a factor of about 2.5.NAS was correct then and wrong now. Climate models have enormous difficulty merely distinguishing the effects of natural influences from anthropogenic (“manmade”) factors when used to explain the causes of changes in broad, long-term climate phenomena. Because a specific weather event — statistically, a single observation — is driven by a complex mix of innumerable factors, it cannot be explained as the result of several factors, only one of which is increases in atmospheric concentrations of greenhouse gases. A given combination of factors might produce a given weather event, and a different combination of factors might do the same.