The report reveals that extreme heat was linked to 710,000 deaths globally in 2023, the highest annual figure during the 2016–2025 period. Vulnerable populations, including infants and older adults, are at heightened risk of heat-related illnesses and mortality. Climate change has contributed to nearly three million heat-related deaths globally between 2016 and 2023, underscoring the urgent need for stronger climate policies and healthcare preparedness.