Abstract Current predictions of climate change impacts rely on conservative assumptions about a lack of adaptation, projecting significantly increased heatwave mortality. However, long-term studies have shown a decline in actual heatwave deaths, raising questions about the underlying mechanisms. We combined Eurostat weekly mortality data (baseline extracted via Seasonal-Trend decomposition by Loess and smoothed through Principal Component Analysis dimension reduction and reconstruction) with economic indicators, Copernicus temperature data since 1950, and ENTSO-E electricity demand data. Panel regression analyzed mortality patterns during weeks with daily temperatures exceeding 22 °C for 2000–2022. During the analyzed period, Europe outpaced climate change, with the capacity to tolerate an additional 1 °C rise every 17.9 years [95% CI 15.3–22.7]. Extending the temperature indicators beyond the prior 3 years did not enhance predictive accuracy, suggesting swift adaptations and historical climate lacked any predictive value. Additionally, increasing economic output, likely driven by infrastructural improvements, especially greater affordability of air conditioning, enabled tolerating each additional 1 °C due to a per capita GDP increase of 19.7 thousand euros [95% CI 14.6–30.3]. Consistently, the increase in cooling energy demand was the strongest in eastern Europe. The findings shed light on the mechanisms driving the observed reduction in heatwave mortality despite the warming climate trend, offering a more plausible basis for extrapolation than assuming a lack of adaptation. The model emphasizes the role of long term economic growth and addressing energy poverty.