Conditional attribution and socioeconomic exposure of the March 2026 North America early heatwave

In March 2026, an intense and spatially extensive heatwave affected a large portion of the North America. Here, we assess the influence of anthropogenic climate change and natural variability on the event using the ClimaMeter analogue-based attribution protocol applied to ERA5 reanalysis. We compare present-day circulation analogues (1988–2025) of March 2026, with analogues from a cooler past climate (1950–1987). We find that events similar to the March 2026 heatwave are associated with near-surface temperatures that are typically 1°C to 3°C warmer in the present climate than in the past, with locally larger increases. By looking at natural variability modes, we observe that human-driven climate change substantially amplified the thermal hazard of the event, while natural variability had only a limited influence on the circulation pattern associated with the event. We further integrate the meteorological attribution with an exposure analysis, combining the heat hazard with gridded population and gross domestic product. We find that nearly 50 million people and more than 2.5 trillion USD in economic assets were located in areas where the heat hazard coincided with a statistically significant climate change amplification of temperature. This underscores the growing contribution of anthropogenic climate change to heat risk amplification across the North America.