In a stark and urgent revelation, the 2025 report by the Lancet Countdown on Health and Climate Change underscores the devastating human toll exacted by continued reliance on fossil fuels and a global failure to aggressively address climate adaptation. This comprehensive study, led by University College London in partnership with the World Health Organization and informed by 128 experts worldwide, reveals that a majority of health-related climate indicators have reached unprecedented, alarming levels. The intertwining crises of climate change and health deterioration highlight a planetary emergency with profound implications for global public health infrastructures and economic stability.
The report presents sobering figures: heat-related mortality has jumped by 23% since the 1990s, currently accounting for approximately 546,000 fatalities annually. The year 2024 alone witnessed a record 154,000 deaths attributable to airborne particulates from wildfire smoke, a phenomena exacerbated by increasingly arid and erratic climatic conditions. Moreover, vector-borne diseases are on the rise, with the potential transmission of dengue fever increasing by nearly 50% since the mid-20th century. These trends reflect an intensification of climate-linked health hazards that are ravaging vulnerable populations globally.
Central to the report’s grim narrative is the role of air pollution, predominantly from fossil fuel combustion, which remains a leading cause of mortality. An estimated 2.5 million annual deaths are directly attributable to polluted air, underscoring the critical intersection of energy policy and health outcomes. This persistent pollution burden places immense financial strain on nations, evidenced by the staggering $956 billion dispensed worldwide in fossil fuel subsidies in 2023 alone—a figure that far outpaces investments in climate resilience and public health. In parallel, major fossil fuel corporations continue to expand production plans at a scale incompatible with planetary survival, threatening to push global warming beyond manageable thresholds.
Despite the grim global backdrop, the report also chronicles tentative progress. Transitioning away from coal combustion has already yielded significant health dividends, preventing an estimated 160,000 premature deaths annually due to cleaner air. Renewable energy deployment reached an all-time high, accompanied by burgeoning employment in green sectors, with more than 16 million jobs linked to renewable energy worldwide. These developments reveal the nascent but critical leadership role of local governments, civil society, and the healthcare sector in spearheading interventions that simultaneously mitigate climate change and bolster population health.
Environmental stressors induced by climate change are advancing rapidly. The year 2024 was recorded as the hottest on earth, causing widespread health and socio-economic disruptions. Average global exposure to extreme heat has surged, with the most vulnerable age groups—infants and the elderly—facing dramatic upticks in heatwave days, exceeding 300% increases compared to past decades. This rise in thermal exposure translates directly into heightened morbidity and mortality rates, overwhelming healthcare services and eroding community resilience.
Compounding the health burden, escalating wildfire incidents produce fine particulate matter (PM 2.5) pollution which disproportionately affects respiratory and cardiovascular health, contributing to tens of thousands of deaths annually. The report further documents severe droughts and heatwaves that have intensified food insecurity, impacting an additional 123 million people compared with historical averages. These climatic extremes impair agricultural productivity and nutrition, threatening food systems at their core and exacerbating diet-related illnesses.
Energy poverty remains a stubborn barrier to health equity. Over 2 billion people worldwide still rely on polluting and unreliable energy sources in their homes, such as biomass and solid fuels. This reliance generates indoor air pollution which claimed 2.3 million lives in 2022 in just 65 low-access countries, compounding ambient air pollution deaths. Such indoor exposures represent a critical but often under-addressed nexus of climate and health vulnerability in marginalized communities.
The economic ramifications of climate-induced health impacts are equally devastating. Labor productivity losses attributable to heat stress reached a record 639 billion potential hours in 2024, equating to an economic shock in excess of one trillion US dollars—a staggering 1% of global GDP. Concurrently, the financial costs associated with heat-related senior mortality escalated to historic peaks near $261 billion. These losses underscore the critical need for integrating health considerations into climate policy and economic planning.
Paradoxically, fossil fuel subsidies have ballooned amid soaring global energy prices, with many governments prioritizing short-term affordability over long-term sustainability. This fiscal strategy aggravates health risks by perpetuating fossil fuel dependence and polluting air quality. Alarmingly, some of the world’s highest-emitting countries allocate more resources to fossil fuel subsidies than to their entire health budgets, a mismatch that imperils population health and undermines climate mitigation efforts.
Financial support for climate adaptation remains critically inadequate, hampering efforts to protect communities from intensifying climate hazards. The report highlights a chilling trend of reduced foreign aid from wealthy nations to climate-vulnerable countries, deepening global inequities and leaving billions exposed to avoidable health risks. This funding gap threatens to unravel fragile health systems and stymie progress in building climate resilience globally.
The fossil fuel industry’s expansion continues unabated, with the top hundred companies projecting production levels that could triple those compatible with the 1.5°C global temperature goal. This expansion is facilitated by unprecedented financial backing from major global banks, which in 2024 collectively funneled $611 billion into fossil fuel ventures—surpassing investments in the green energy sector. Such trends exacerbate greenhouse gas emissions, perpetuate health hazards, and destabilize economies reliant on fossil fuel extraction.
Deforestation compounds climate challenges by eroding biodiversity and natural carbon sinks, with over 128 million hectares of forest lost in 2023 alone—a 24% increase from the previous year. This large-scale forest destruction diminishes the planet’s capacity to moderate climate change impacts, further accelerating the frequency and intensity of extreme weather and health emergencies. The loss of natural ecosystems is deeply intertwined with escalating risks to human wellbeing.
Nonetheless, grassroots and sectoral initiatives illuminate a pathway forward. The health sector has demonstrated commendable leadership by reducing its own greenhouse gas footprint by 16% in a single year and integrating climate-health education into medical curricula globally. Urban centers are increasingly conducting climate risk assessments, with over 800 cities actively engaging in adaptation planning. These bottom-up movements generate momentum that could catalyze broader systemic transformations toward sustainable, health-centric climate action.
In conclusion, the 2025 Lancet Countdown report casts a revealing light on the catastrophic health consequences wrought by delayed climate action and fossil fuel dependence. It calls for an all-encompassing, multisectoral response to expedite decarbonization, enhance adaptation financing, and embed health equity at the core of climate policies. The convergence of climate science and public health imperatives demands urgent, coordinated global efforts to avert a spiraling health crisis and secure a sustainable future for billions worldwide.
Subject of Research: People
Article Title: The 2025 report of the Lancet Countdown on health and climate change
News Publication Date: 29-Oct-2025
Web References: DOI link
Keywords: Health and medicine, Climate change
