A comprehensive report on climate change and human health released this week concludes that the global health crisis from rising temperatures is accelerating faster than governments and institutions are responding to it.

The 2026 Lancet Countdown on Health and Climate Change, led by University College London in collaboration with the World Health Organization, compiled research from 146 experts at more than 100 institutions across more than 30 countries. The report tracks 54 health indicators related to climate impacts, energy systems, adaptation, research funding, and extreme weather events. It was published on Tuesday, 2026-10-27, ahead of the 31st UN Conference of the Parties climate summit in November.

The report documents a sharp rise in heat-related deaths since the Paris Agreement was adopted in 2015. Between 2016 and 2023, heat was linked to an average of 540,800 estimated deaths per year, with 68 percent (approximately 369,900) attributed to climate change—a significant increase from 55 percent in the prior decade of 2006–2015. In 2023 alone, the hottest year in that period, heat was linked to a record 710,000 deaths, with 71.5 percent attributable to human-caused climate change. That single year's toll exceeded global deaths from malaria or HIV, according to the researchers. Across the entire 2016–2023 span, climate change is estimated to have caused nearly 3 million heat deaths.

"A decade after the Paris Agreement, our findings are unambiguous: the health harms of climate change are growing faster than the world's response to them, and in many cases even accelerating," said Marina Romanello, executive director of the Lancet Countdown at University College London, in a statement. She added that while progress has been made in clean energy, health system readiness, and health-protective regulation, "progress has been too slow, too small, and isn't reaching those who need it most."

Beyond deaths, climate change is exacting a severe economic toll. Heat reduced workers' capacity to work productively in 2025, costing the global economy an estimated $1.07 trillion in potential income—equivalent to 0.91 percent of global economic output. This marks the third consecutive year that heat-related productivity losses exceeded $1 trillion. Southeast Asia and Africa were hit hardest, with losses equivalent to 3.9 percent and 3.2 percent of their respective GDP, compared with 0.2 percent in Europe and 1.5 percent in the Americas. Agriculture and construction, both outdoor and physically demanding sectors, absorbed the largest share of losses at 38 percent and 29 percent respectively.

Extreme weather patterns are also shifting. More than half the world's land (51.8 percent) experienced extreme drought for at least a month in 2025, the second-worst year on record after 2023. Since 2016, the area affected by drought has grown more than 700 percent faster than it did in the preceding decade. Using new satellite-based analysis, researchers also found that 80 percent of the world's land has experienced significant shifting patterns of increasing dry and wet groundwater storage conditions since 2003, with widespread impacts on food security and sanitation.

Despite the escalating crisis, the report identifies some progress. Global investment in clean energy reached a record $2.1 trillion in 2025—approximately 82 percent more than was invested in fossil fuel energy sources. Renewables grew from 5.5 percent of global electricity generation in 2016 to 13.5 percent in 2023. Additionally, cleaner air prevented an estimated 323,000 deaths per year in at least 77 countries where air pollution from fossil fuels has fallen since 2016. Fifty-six of the World Health Organization's 194 member states have adapted their health and early-warning systems to anticipate extreme events.

However, researchers emphasized that fossil fuels still supply more than 80 percent of global energy and continue to produce planet-heating emissions. The world's 100 largest oil and gas companies are on track to exceed production levels compatible with limiting warming to 1.5 degrees Celsius by 150 percent by 2040, according to the report. The experts called for climate change to be formally recognized as a global health emergency, with health placed at the center of climate policy decisions and funding priorities.