Climate Change Impact: Rising Global Health and Infectious Disease Risks

Climate change is increasingly jeopardizing global health, intensifying the risks posed by infectious diseases. Experts warn that shifting weather patterns and rising temperatures are altering disease transmission, straining public health systems worldwide and complicating efforts to control outbreaks.

Silent Health Crisis Unfolding

As the planet warms, the scale of the health emergency triggered by climate change is becoming impossible to ignore. According to the latest report from The Lancet Countdown, published on October 29, 2025, an average of 546,000 people died each year between 2012 and 2021 directly because of extreme heat—a staggering 63% increase since the 1990s. Even when adjusting for population growth, heat-related mortality climbed nearly a quarter. Regions including Africa, the Middle East, and South Asia remain especially vulnerable, bearing a disproportionate share of this mounting toll.

From Air Pollution to Deadly Heatwaves

These figures only scratch the surface of a deeper crisis. Over the past two decades, individuals have found themselves enduring more than triple the amount of dangerous heat exposure compared to before. At the same time, air pollution—much of it driven by fossil fuel use—continues to take a deadly toll. The report estimates that in 2022 alone, over 2.5 million deaths worldwide could be traced back to air pollution, with slight improvements in some developed countries thanks to reduced coal dependency.

Worsening heat waves compound other health threats: kidney or heart complications can strike without warning under persistent high temperatures, sometimes resulting in sudden death. Less visible but just as damaging are disruptions to sleep and reduced physical activity—two fundamental elements for overall well-being.

Several factors explain this decision:

• 16,000 deaths from extreme weather events like droughts and storms occurred in 2024.
• A record-breaking 154,000 deaths linked to wildfire smoke were reported that same year.
• Soaring food insecurity affected over 123 million people due to worsening droughts and heatwaves.

Disease Risks Expanding Their Reach

But perhaps most alarming is how vector-borne diseases are proliferating as global temperatures rise. The spread of mosquitoes like the Asian tiger mosquito has dramatically increased the risk of dengue: global transmission potential has surged by more than half since the mid-20th century, with over seven million cases logged worldwide in just one year. Other insects—ticks responsible for hemorrhagic fevers and sandflies carrying leishmaniasis—are also expanding into new territories as climates shift.

An Urgent Call for Change

What emerges from this year’s Lancet Countdown report is sobering: climate change is not only intensifying natural disasters but also destabilizing the very foundation of human health across continents. As governments and communities confront these realities, one thing is clear: rethinking priorities has never been more urgent if we are to avoid even greater losses in years ahead.