Distinct Characteristics of Contiguous Heatwaves Across Terrestrial, Marine, and Coastal Environments

Abstract Atmospheric extreme heat is intensifying across terrestrial, marine, and coastal environments, impacting ecosystems, society, and other extremes, such as drought and marine heatwaves. We quantify the characteristics of contiguous near‐surface heatwaves using ERA5 (December 1940–November 2024) and find significant differences across these environments. Coastal heatwaves exhibit higher mean and peak intensity compared to terrestrial and atmospheric marine heatwaves in tropical and temperate regions, while peak intensity of polar coastal heatwaves is also significantly higher. We find that peak intensity decreases with distance from the coastline. We observe significant increases in frequency, concurrence, duration, and spatial extent, with more rapid increases during 1990–2024 compared to 1940–1989. The El Niño‐Southern Oscillation significantly influences interannual variations in heatwave frequency in tropical regions. Our findings provide important insights into extreme heat across terrestrial, marine, and coastal environments which can aid in societal adaptations under global warming.