How many people have died because of climate change?

In 2003 and 2004, a pair of studies led by Australian epidemiologist Anthony McMichael tried to calculate the global burden of disease due to climate change. They estimated that in the year 2000, climate change was already killing at least 455 people every day.

Based on the McMichael study, by 2025, at least 4 million people have died — making climate change deadlier than most pandemics or public health emergencies. But since 2004, global warming levels have more than doubled, from 0.6 °C to +1.3 °C, and scientists have gotten better at measuring the health effects of climate change. So why haven’t we updated these estimates for more than 20 years?

It’s time to get back to work.