Climate Change Is Driving More Heat Deaths, Food Shortages and Infectious Diseases, Report Finds

More people are dying, falling ill and suffering economic impacts as a result of climate change. In 2023, one of the warmest years on record, around 710,000 deaths were linked to extreme heat. More than 70 percent of these deaths were linked to human-caused climate change. That is more than the number of people who died from malaria or HIV, according to the researchers behind a new report.

“The climate crisis is having serious, damaging consequences for human health. From deadly heatwaves and floods to food insecurity, pollution and disease,” said UN climate chief Simon Stiell in a press statement.

Over the past decade, health risks from global warming have accelerated, according to a report from the Lancet Countdown initiative, published ahead of the UN climate summit COP31.

Costly for societies

The report, produced in collaboration with the World Health Organization (WHO), shows that heat-related deaths have increased by nearly 36 percent globally since 2016. In addition to putting strain on the heart and other organs, heat can make many diseases spread more easily in a changing climate. Diseases such as dengue fever and West Nile fever are increasing and spreading to new parts of the world as the climate changes.

In addition, in 2025, more than half of the world's land area was affected by extreme drought for at least one month, with major consequences for, among other things, groundwater levels and harvests. This poses serious threats to drinking water and food supplies, which also creates health risks.

"No gradual deterioration"

Since more than 80 percent of the energy we use still comes from fossil fuels, the threats will grow, according to the report. The authors call for health to be placed at the center of all climate decisions and for international aid and climate adaptation to be strengthened.

"This is not gradual deterioration, but a shift that must be recognized as the global health emergency that it actually is," says Marina Romanello, a researcher at University College London who led the work on the Lancet Countdown, in a comment.