The July 2026 North American wildfire smoke event was three times deadlier due to climate change
Abstract
In mid-July 2026, numerous fast-burning wildfires affected western Ontario and northern Minnesota, resulting in extensive smoke across eastern North America. Here, we conduct a rapid attribution analysis of the 14–21 July smoke event, quantifying the change in wildfire smoke (WFS) PM2.5 concentrations and mortality compared to a counterfactual world without anthropogenic climate change (ACC). We find that ACC increased WFS PM2.5 concentrations by approximately three-fold. As a result, population exposure to regulatory exceedances of WFS PM2.5 concentrations (>35 µg/m3) amounted to 268 million person-days, of which 157 million are attributable to ACC. We estimate 770 excess deaths attributable to observed WFS PM2.5 exposure, a three-fold increase compared to the counterfactual scenario. This rapid impact-attribution assessment of WFS PM2.5-related mortality provides a methodological framework for quantifying the ACC contribution to other acute air pollution episodes globally.
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BibTeX
@misc{kalashnikov2026july,
title = {{The July 2026 North American wildfire smoke event was three times deadlier due to climate change}},
author = {Dmitri A. Kalashnikov and Emily L. Williams and John Abatzoglou and Cong Yin and Wenli Ni and Nicholas Nassikas},
howpublished = {EarthArXiv},
year = {2026},
month = oct,
doi = {10.31223/x51z3h},
url = {https://eartharxiv.org/repository/view/15486/},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The July 2026 North American wildfire smoke event was three times deadlier due to climate change
AU - Dmitri A. Kalashnikov
AU - Emily L. Williams
AU - John Abatzoglou
AU - Cong Yin
AU - Wenli Ni
AU - Nicholas Nassikas
PY - 2026
DA - 2026/10/13
PB - EarthArXiv
DO - 10.31223/x51z3h
UR - https://eartharxiv.org/repository/view/15486/
AB - In mid-July 2026, numerous fast-burning wildfires affected western Ontario and northern Minnesota, resulting in extensive smoke across eastern North America. Here, we conduct a rapid attribution analysis of the 14–21 July smoke event, quantifying the change in wildfire smoke (WFS) PM2.5 concentrations and mortality compared to a counterfactual world without anthropogenic climate change (ACC). We find that ACC increased WFS PM2.5 concentrations by approximately three-fold. As a result, population exposure to regulatory exceedances of WFS PM2.5 concentrations (>35 µg/m3) amounted to 268 million person-days, of which 157 million are attributable to ACC. We estimate 770 excess deaths attributable to observed WFS PM2.5 exposure, a three-fold increase compared to the counterfactual scenario. This rapid impact-attribution assessment of WFS PM2.5-related mortality provides a methodological framework for quantifying the ACC contribution to other acute air pollution episodes globally.
ER -