As heatwaves grip continents and push temperatures to dangerous extremes, the United Nations marked the first anniversary of its Call to Action on Extreme Heat on July 25, urging global leaders to treat rising heat as an urgent health and climate crisis.
Nearly 100 million people in the United States alone were under heat alerts this week, while Europe, Asia, North Africa, and Latin America continue to battle escalating heat emergencies. From power outages in Iran to wildfire-triggered evacuations in Greece, the impact of extreme heat is no longer seasonal it’s becoming a year-round global threat.
“Extreme heat is sometimes called the silent killer, but with today’s science, data, and technology, silence is no longer an excuse,” said Ko Barrett, Deputy Secretary-General of the World Meteorological Organization (WMO).
To address the crisis, the Global Heat Health Information Network (GHHIN), WMO, and UNDRR have launched new tools under the initiative Supporting Extreme Heat Risk Governance. These include a global stocktake report of UN heat efforts, assessments of national heat action plans, and real-world case studies from 12 countries such as India, Bangladesh, Argentina, and Senegal.
The data paints a grim picture: between 2000 and 2019, an estimated 489,000 people died each year due to heat-related causes, nearly half of them in Asia. Officials warn that actual figures may be much higher due to underreporting.
“This is not just a climate issue it’s a public health emergency,” said Dr. Joy Shumake-Guillemot, who co-leads GHHIN and heads the WHO-WMO Joint Climate and Health Office.
In response the Early Warnings for All campaign is being scaled up to protect vulnerable populations with timely, localized alerts. Experts estimate that expanding these systems to just 57 countries could prevent nearly 100,000 deaths annually.
The UN heat response strategy is built around four pillars: protecting vulnerable populations, improving workplace safety, strengthening resilience using science and data, and limiting global warming to 1.5°C.
Backed by $11.5 million in new support from the Rockefeller Foundation and Wellcome the initiative is accelerating local adaptation just as global leaders prepare for the 2025 COP30 summit in Brazil where health-focused climate action will take center stage.
As global temperatures continue to rise the UN message is clear: every life lost to extreme heat is preventable. The tools exist what needed now is urgency, investment, and action.