A global assessment of urban extreme weather early warning systems and public health engagement.

Objective: To assess extreme weather early warning systems in large cities across the world. Methods: Among cities with populations above 1 million reporting to the Carbon Disclosure Project Cities Adaptation Actions database from 2021 to 2023, we included those providing a description of at least one adaptation action for a climate hazard in at least one year. We identified cities reporting early warning systems using the United Nations Early Warnings for All framework, which includes four pillars: risk knowledge, hazard monitoring and forecasting, warning communication and preparedness. We also tracked public health engagement in these systems. Findings: We identified 182 cities, of which 71 described full early warning systems across the four pillars. Cities in high- and upper middle-income countries described early warning systems nearly three times more often than those in low- and lower middle-income countries. Multihazard early warning systems  were reported by 35 (49%) cities, and many of these involved institutionalized cross-sectoral coordination and funded at least one activity from their own resources. Health was reported as a goal of early warning systems by 58 (82%) cities, although just 29 (41%) indicated a specific role for public health agencies. Conclusion: These findings suggest that many large cities are not covered by these health-protective systems. We recommend development of a city-specific framework for early warning systems that identifies roles for health, and scaling up of these tools, particularly in cities in low- and lower middle-income countries, to ensure strengthened adaptive urban resilience against climate threats.