This story is part of the Grist series Vital Signs, exploring the ways climate change affects your health. This reporting initiative is made possible thanks to support from the Wellcome Trust.
As the world readies for the pivotal COP30 climate summit in Brazil, a recent publication highlights a grim reality: climate change is claiming millions of lives each year. The “Countdown on Health and Climate Change,” an annual analysis since 2015 by The Lancet, reveals a troubling escalation in climate-related health impacts.
Over the years, the severity of these reports has increased. In 2020, the findings indicated that climate shifts could reverse five decades of public health progress. The latest edition confirms that this reversal is indeed occurring.
“Climate change is increasingly destabilising the planetary systems and environmental conditions on which human life depends,” the countdown’s authors emphasized.
The report states that extreme heat is now causing one death per minute, highlighting a 23% rise in heat-related fatalities since the 1990s, largely attributed to fossil fuel-induced global warming. Had climate change not progressed, many of the heatwave days recorded between 2020 and 2024 might have been avoided.
Beyond heat, threats include wildfire smoke inhalation and infectious diseases like dengue fever, both on the rise. In 2024, deaths from wildfire smoke rose 36% above the baseline from 2003-2012. Furthermore, increased droughts and heatwaves led to 124 million more people facing food insecurity in 2023 compared to the 1981-2010 average.
This analysis portrays societies struggling to adapt to evolving environmental conditions. Harjeet Singh, from the Satat Sampada Climate Foundation, remarked, “This Lancet report is a devastating global health audit. Our fossil fuel addiction is killing us by the millions.”
Disentangling the specific impacts of climate change on health remains complex. Human health is influenced by numerous factors, both internal and external. Researchers have long been trying to distinguish the role of climate change in health trends, akin to how scientists attribute specific weather events to climate conditions.
The variability in human responses makes attributing health outcomes to climate change an imperfect science. For instance, climate-related fatalities are often underreported in areas like Arizona during intense heatwaves, as seen in recent studies. Conversely, the spread of diseases like Lyme may overemphasize climate influence while downplaying factors like urbanization.
The significance of The Lancet’s annual report lies in its comprehensive assessment of climate and health research. It examines 20 health indicators, including air quality and food availability. The 2025 report notes that 13 of these indicators have worsened over the past year.
As global leaders gather in Brazil, the drive for united climate action seems to be faltering. Major fossil fuel firms, including BP and ExxonMobil, have backtracked on climate pledges. The U.S., under President Donald Trump, has started exiting the Paris Agreement and the World Health Organization.
The report’s authors warned, “Paradoxically, as the need for decisive health-protective action grows, some world leaders are disregarding the growing body of scientific evidence on health and climate change. There is no time left for further delay.”
Original Story at grist.org