Climate Inaction Costs Lives, Strains Health Systems: Lancet

A new global report warns that climate inaction is already causing widespread health impacts, including hundreds of thousands of deaths annually, while placing significant strain on health systems and economies.

The 2025 Lancet Countdown on Health and Climate Change, released in collaboration with the World Health Organization (WHO), shows that 12 of 20 key indicators tracking health threats linked to climate change have reached record levels. The report highlights the immediate human costs of continued reliance on fossil fuels and insufficient adaptation to rising global temperatures.

“The climate crisis is a health crisis. Every fraction of a degree of warming costs lives and livelihoods,” said Dr. Jeremy Farrar, Assistant Director General for Health Promotion and Disease Prevention and Care, WHO. “This report makes clear that climate inaction is killing people now in all countries. However, climate action is also the greatest health opportunity of our time.”

The report notes that heat-related deaths have increased 23% since the 1990s, with an average of 546,000 deaths per year. In 2024, people were exposed to an average of 16 days of dangerous heat, with infants and older adults experiencing over 20 heatwave days per year. Droughts and heatwaves contributed to moderate or severe food insecurity for an additional 124 million people in 2023.

Economic impacts are significant, states the ILO. Heat exposure led to an estimated 640 billion potential labor hours lost in 2024, equating to US$1.09 trillion in productivity losses, while costs associated with heat-related deaths among older adults reached US$261 billion. Governments spent US$956 billion on fossil fuel subsidies in 2023, more than three times the annual funding pledged to climate-vulnerable countries. Fifteen countries allocated more to fossil fuel subsidies than to their entire national health budgets.

The report also identifies the benefits of climate action. Between 2010 and 2022, reducing coal-related air pollution prevented an estimated 160,000 premature deaths annually. Renewable energy generation reached 12% of global electricity, creating 16 million jobs, and two-thirds of medical students received education on climate and health in 2024.

Dr. Marina Romanello, Executive Director, The Lancet Countdown at University College London, emphasized that solutions exist. “Rapidly phasing out fossil fuels in favor of renewable energy and efficient energy use remains the most powerful lever to slow climate change and protect lives. Shifting to climate-friendly diets and sustainable agriculture could potentially save over 10million lives a year.”

The report shows that cities, communities, and the health sector are leading climate action. Nearly all reporting cities have completed or plan to complete climate risk assessments. Globally, health-related greenhouse gas emissions fell 16% between 2021 and 2022. Fifty-eight percent of WHO Member States have completed health vulnerability and adaptation assessments, and 60% have finalized national adaptation plans for health.