Adaptation in the Era of Extreme Heat: Tackling Irreversible Losses to Health and Wellbeing

The year 2024 was the hottest on record, continuing a decade-long trend of unprecedented global temperatures. All of the past ten years now rank among the hottest ever recorded. January 2025 has already set a new record as the warmest January, signaling another year of escalating global temperatures marked by extreme heat.

Climate Change Driving Extreme Heat

The planet is surpassing past heat records at an alarming rate. In India, for instance, the heatwave season has arrived unusually early, with temperatures along the west coast soaring in February. Scientists attribute this early onset to an exceptionally dry winter, among other factors. This period of extreme heat extends beyond typical seasonal patterns and geographical expectations, underscoring the growing severity of climate change.

The World Weather Attribution (2024) reports that climate change contributed to at least 3,700 deaths and the displacement of millions across 26 extreme weather events in 2024. Scientists also found that climate change added 41 extra days of “dangerous” heat that year.

Record-breaking global temperatures in 2024 led to extreme rainfall events, triggering catastrophic flooding. Of the 16 floods studied, 15 were directly linked to climate change-driven rainfall, demonstrating how rising temperatures are amplifying weather disasters worldwide.

Health Risks Amplified

Extreme heat poses severe health risks, as highlighted in a comprehensive analysis of temperature-attributable mortality worldwide. A study analyzing data from 65 million deaths across nine countries found that extreme temperatures—both heat and cold—are linked to 17 causes of death, primarily cardiorespiratory and metabolic diseases. In 2019 alone, an estimated 1.7 million deaths worldwide were associated with extreme temperatures, with at least 356,000 specifically attributed to heat.

Research published in The Lancet’s Heat and Health Series (2021) underscores how heat directly impacts the human body, leading to dehydration, cardiovascular strain, and other health complications. The findings reinforce the role of temperature as a major amplifier of health risks, particularly in vulnerable populations and high-exposure settings. This means global warming is more than a purely environmental issue—it is also a public health issue.

Limit to Extreme Heat Adaptation

Efforts to adapt to extreme heat, particularly in the context of public health, have led to the development of Heat Action Plans (HAPs). These plans incorporate early warning systems, community engagement, targeted outreach to at-risk populations, and cross-sectoral collaboration.

While HAPs have shown promising results in mitigating heat-related health risks at the local level, rapidly rising temperatures demand more effective and science-driven interventions. To enhance their impact, HAPs must integrate the latest scientific findings, establish localized temperature and humidity thresholds for high-risk urban areas, and utilize risk analytics to better identify and protect the most vulnerable populations.

Paradigm Shift and Better Risk Assessment

Current approaches primarily focus on emergency response, but a paradigm shift is urgently needed. Shifting from a short-term, reactive approach to long-term, transformative strategies is essential. This involves strengthening mitigation and adaptation measures while addressing loss and damage caused by extreme heat. In short, we need a new framework that anticipates risks, absorbs shocks, and strategizes long-term solutions.

To begin, accurately quantifying heat-related health risks is essential for reducing morbidity and mortality caused by heat stress. The Heat Index, developed in 1979, was designed to convey human discomfort under typical temperature and humidity conditions in the United States. However, it was built on simplified assumptions that do not adequately reflect the extreme temperatures and humidity of today’s intensified heatwaves.

A recommended tool to improve risk assessment is Extended Heat Index (EHI), capable of capturing heat stress even under extreme conditions. Scaling the EHI across diverse climate and socio-economic vulnerability contexts will provide a more accurate measure of heat exposure.

Translational Science for Comprehensive Strategy

Furthermore, adopting a broader strategy that integrates non-economic loss and damage (NELD) factors into heat management frameworks is essential. It is important to understand the full spectrum of NELD associated with extreme heat, particularly in vulnerable groups such as children, adolescents, youth, and the elderly.

Translational science—the process of applying scientific discoveries to real-world health challenges—plays a crucial role. It offers an opportunity to enhance planning, assessment, and technical support, strengthening global coordination efforts, such as by developingNELD accounting tools that integrate climate, disaster, and health nexus metrics.

An example of this concept is an easily executable Heat Stroke Score System, HISS, developed and implemented by the Centre for Disaster Management at Kasturba Medical College in India.  The Warsaw International Mechanism (WIM) on Loss and Damage provides a critical platform to expand these initiatives, ensuring that both immediate and long-term health impacts of extreme heat are systematically addressed.

Tackling extreme heat and cooling everything down requires robust collaboration from scientists, governments, and other relevant stakeholders across multiple sectors. After all, heat affects not only physical and mental health but also critical aspects of human development, including growth, learning, wellbeing, and long-term potential.

Editor: Nazalea Kusuma

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