Quantitative attribution of climate change effects on the 2023 North China heatwave

In early summer 2023, an extreme heatwave swept across North China (NC), with the regional average maximum temperature reaching its highest level since 1961, which pose severe risks to socio-ecological systems. The record-breaking June–July 2023 heatwave in NC, characterized by concurrent precipitation deficits and elevated potential evapotranspiration. The most intense and prolonged phase of the event, spanning 20 June to 4 July (P2), was primarily driven by dry static energy convergence associated with enhanced downgradient transport. Strong land–atmosphere feedbacks further amplified near-surface warming by translating circulation-induced energy accumulation and the effects of dry soils into higher temperatures. Meanwhile, persistent high-pressure anomalies sustained and intensified the heatwave. To quantify the contribution of climate change, we conducted a quantitative attribution analysis using the Weather Research and Forecasting (WRF) model, with initial and boundary conditions constrained by detrended long-term climate trends from the Canadian Earth System Model version 5 Large Ensemble Project. Results indicate climate warming contributed approximately 2.1 °C to the heatwave intensity and a 91.2 mm precipitation deficit. Thermodynamic processes dominated these changes, accounting for 92.8% of the warming and 94.1% of the precipitation reduction, primarily by enhancing land–atmosphere interactions. Warming also promoted the development of tropospheric high-pressure anomalies over NC, which amplified the event through reductions in latent heat flux and soil moisture, and increases in sensible heat flux. Soil-moisture sensitivity experiments further indicate that extreme warming and drying were mainly sustained by large-scale circulation induced subsidence. These findings underscore the critical role of climate change in amplifying heatwaves via thermodynamic and dynamic processes and highlight the urgent need for adaptation measures to address escalating heat-related risks.