Climate Change Has Killed At Least 4 Million People Since 2000

In the early 2000s, as climate denialism was infecting political institutions around the world like a malevolent plague, an Australian epidemiologist named Anthony McMichael took on a peculiar and morbid scientific question: How many people were being killed by climate change? McMichael’s research team tallied up how many lives had been lost to diarrheal disease, malnutrition, malaria, cardiovascular disease (a proxy for heat-related illness), and flooding, worldwide, in the year 2000. The researchers then used computer modeling to parse out the percentage of those deaths that were attributable to climate change. Climate change, they estimated, was responsible for 166,000 lives lost that year.

The world has changed a great deal since. Climate denialism is no longer the world’s de facto climate policy, in large part because the impacts of rising temperatures have become impossible to ignore. The field of climate research has grown apace, and the science behind how climate change affects everything from ultra-rare species of frogs to the velocity of baseballs to the intensity of heatwaves, droughts, floods, and hurricanes has become astonishingly precise. But the research assessing how many people are currently being killed by the climate crisis has remained conspicuously stagnant. While a small handful of studies have attempted to quantify the effect of climate change on mortality decades into the future, the McMichael standard, an ambitious relic of the early 2000s, is still the only estimate of its kind.