It’s hard not to notice when Michael Mann’s name appears in the author list of a climate paper—after all, he’s about as synonymous with climate alarm as Al Gore is with PowerPoint slides. One could say spotting his name in a paper about “intensification of the strongest nor’easters” is like finding Waldo in a crowd where everyone’s wearing a red-and-white striped shirt—inevitable, but somehow still amusing.
To the meat of the matter: this paper by Chen et al., published in PNAS in July 2025, claims that the strongest nor’easters affecting the U.S. East Coast are not only getting stronger in terms of maximum wind speed, but also producing more precipitation over time, especially since 1940. Naturally, this finding is attributed to—you guessed it—“a warming world,” though, as is tradition, the underlying uncertainties and methodological sleights-of-hand are tucked away in the statistical shadows.
The paper leans heavily on reanalysis data (ERA5, 1940–2025) and cyclone tracking algorithms to cobble together a historical record, touting its “homogeneity” and “comprehensiveness.” Yet, buried within the technical details, there is acknowledgment that models and data sources are patchy at best, especially in the pre-satellite era—a recurring Achilles’ heel in this field. Indeed, the authors admit:
“The precise significance levels vary depending on the choice of statistical test, time interval, and effective storm radius… Of specific potential concern is the sensitivity of the trend to changes in input data sources during the transition from traditional surface and radiosonde observations in the early part of the record to multisensor observations in later years. However, we find that the trends of interest are even greater in magnitude… if confined entirely to the satellite era (1979–2025)…”
In other words: the “clear finding” that nor’easters are becoming more intense is more “clear” the shorter and more satellite-heavy the dataset. It’s a bit like insisting your cooking skills are improving because you swapped out a foggy bathroom mirror for an Instagram filter—suddenly everything looks better, but is it really you that changed, or the tool?
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