Assessing sustained high-heat multi-hazard events through earth observation and impact chain analysis in southeast UK

Sustained high-heat events are increasing in the UK, intensifying risks to health, infrastructure, ecosystems, and water resources. This study investigates whether earth observation (EO) data can identify environmental preconditioning factors and candidate thresholds that signal emerging multi-hazard conditions. Using the 2022 southeast UK heatwave, we analyze climate variables and EO-derived indicators—including land-surface temperature, soil moisture, vegetation stress, and ground motion—at regional and event-specific scales, supported by a hazard impact catalog. Impact-chain analysis reveals how heat, drought, vegetation stress, wildfires, flash flooding, and subsidence interact as compounding and cascading hazards. We find that soil-moisture deficits, elevated surface temperatures, and ground-motion anomalies frequently precede hazardous events, indicating their potential as early-warning signals. This multi-source synthesis provides a semi-automatable workflow and EO-based thresholds benchmarked against a multi-year baseline, offering broader value for monitoring and forecasting high-heat multi-hazard risks under accelerating climate change.