WMO Ramps Up Global Action as Extreme Heat Threatens Millions

As heatwaves grow more intense, frequent, and deadly, the World Meteorological Organization (WMO) and its partners are scaling up global efforts to combat the rising threat of extreme heat, often referred to as a "silent killer." While much of the Northern Hemisphere battles scorching summer temperatures, parts of the Southern Hemisphere, including South America, are enduring unusually severe cold spells—both extremes serving as stark reminders of the mounting health impacts of climate variability and human-induced climate change.

“Extreme heat is not just a seasonal inconvenience—it’s a life-threatening hazard,” said a WMO spokesperson. “With the right coordination and action, we can prevent deaths and protect vulnerable populations.”

Record-Breaking Heat Across Continents

July, typically the warmest month in the Northern Hemisphere, has brought relentless and widespread heat to Western Europe, North Africa, North America, the Middle East, and Central Asia. Driven by persistent high-pressure systems, dry air from the African continent has been trapped over Europe, intensifying daytime and nighttime temperatures.

Notable highlights include:

• Spain: The Agencia Estatal de Meteorología (AEMET) recorded a scorching 46.0°C in southern regions.

• France: Météo-France issued its highest-level red alert for 16 departments on 1 and 2 July, with 68 others under amber alerts as temperatures exceeded 40°C.

• Switzerland: MeteoSwiss issued amber alerts across most areas, including Geneva.

• Morocco: Nationwide heatwave saw temperatures rise above 45°C, according to Maroc Météo.

Additionally, the Mediterranean Sea recorded exceptionally high sea surface temperatures (SSTs) for this time of year, which are further reinforcing land-based heat extremes.

What makes these events especially alarming is their early onset, with such temperatures historically more common in August. The prolonged absence of cloud cover is allowing unfiltered solar radiation to heat surfaces relentlessly, while the urban heat island effect is compounding the crisis in cities by retaining warmth well into the night.

The Health and Urban Impact

The human toll of extreme heat is most acutely felt in urban centers, where paved surfaces, buildings, and vehicle emissions contribute to significantly higher temperatures than in surrounding rural areas. According to the European State of the Climate Report, the urban heat island effect exacerbates heat stress and mortality.

Since 2000, more than two-thirds of Europe’s most severe heatwaves have occurred, a worrying trend confirmed by WMO’s Regional Climate Centre Network and the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report.

The IPCC warns that by 2050, up to 50% of the European population could be exposed to high or very high heat stress risk during the summer—especially in Southern, Eastern, Western, and Central Europe.

A Chilling Contrast in the South

While Europe swelters, South America faced a record-breaking cold snap at the end of June, notably impacting Argentina, Chile, and Paraguay. Though often overshadowed by heatwaves, extreme cold also poses serious public health risks, especially in underserved or poorly insulated communities.

This unusual weather pattern underscores the dual threat of extreme temperatures on both ends of the spectrum, amplified by a warming climate that is disrupting historical norms and straining health systems worldwide.

WMO’s Global Response Framework

In response, WMO is accelerating the implementation of life-saving measures through its “Early Warnings for All” initiative, a strategic effort to ensure every person is protected by early warning systems by 2027.

Key components include:

• WMO Coordination Mechanism (WCM): A global network offering expert advice, crisis monitoring, and real-time situational awareness via data from WMO Members and Centres.

• Global Heat Health Information Network (GHHIN): A partnership with the World Health Organization (WHO) and others, providing national and local governments with the technical guidance and governance tools needed to mitigate extreme heat risks.

• Extreme Heat Risk Governance Project: Supporting policy-makers in developing integrated approaches across climate, health, and emergency sectors. This initiative is helping harmonize responses across government departments to ensure a coordinated and sustainable response to rising temperatures.

In June 2025, GHHIN convened experts from around the world in London to improve the monitoring of heat-related health impacts. The goal is to refine public health surveillance systems, standardize metrics for tracking heat-related illness and death, and improve response times for health agencies and local governments.

Looking Forward

As the planet continues to warm, climate extremes are no longer anomalies—they are becoming the new norm. Whether in the form of searing heat or biting cold, these events demand a systemic and coordinated global response.

WMO and its partners are urging governments to strengthen heat-health action plans, invest in early warning systems, and incorporate climate resilience into urban planning, health services, and infrastructure development.

“We must treat heatwaves with the same urgency as other natural disasters,” said a WMO official. “They are predictable, preventable, and deadly. With the right tools, we can save lives.”

As climate change continues to accelerate, the stakes are higher than ever. The world must act swiftly to adapt, warn, and protect—before the next wave of extreme heat claims more lives.