A Project to Count Climate Crisis Deaths Has Surprising Results

Climate change can kill people in all kinds of ways. There are the obvious ones—wildfires, storms, and floods—yet rising temperatures may also lead to the increased spread of deadly diseases, make food harder to come by, and increase the risk of conflict.

Although we know about these wide-ranging but equally terrifying risks, attempts to pinpoint the number of deaths caused by climate change have been piecemeal. One recent study estimated that climate change was to blame for 37 percent of heat-related deaths over the past three decades. In 2021, Daniel Bressler, a PhD student at Columbia University in New York, estimated that every additional 4,400 metric tons of carbon dioxide emitted will cause one heat-related death later this century. He called this number the “mortality cost of carbon.”

Putting a number on climate deaths isn’t just an academic exercise. People are already dying because of extreme temperature and weather events, and we can expect this to become more common as the planet continues to heat up. If governments want to put in place policies to prevent these deaths, they need a way of accurately measuring the deaths and ill health linked to warming. The search is on for the true mortality cost of carbon.

As part of this search, the UK government has made its first attempt at putting a number on climate change deaths. The UK Office for National Statistics (ONS)—an independent government agency responsible for producing official data—has for the first time reported climate-related deaths and hospital admissions in England and Wales. The report covers the years 2001 to 2020, but future reports will be released annually, revealing for the first time detailed information about the impact that climate change is having on health in the two nations. (Statistics for Scotland and Northern Ireland are recorded separately.)The main finding from this investigation is counterintuitive. The report found that the number of deaths associated with warm or cold temperatures actually decreased between 2001 and 2020. On average, 27,755 fewer people were dying each year due to unusually warm or cold temperatures. In other words, climate change might have actually prevented over half a million deaths in England and Wales over this period. In 2001 there were 993 climate-related deaths per 100,000 people in England and Wales. By 2019 that figure had fallen to 771.But let’s not get ahead of ourselves. There are a number of reasons why the net number of temperature-related deaths appeared to decline over this period, says Myer Glickman, head of the epidemiological, climate, and global health team at the ONS. For a start, statisticians took a relatively narrow definition of climate-related deaths. They only included deaths from conditions where scientists had previously found a clear link between temperature and disease outcome, and they also excluded any health condition where their own analysis showed no link between temperature and outcome. This means that the mortality data doesn’t include deaths from violence or natural forces (such as storms, landslides, or flooding).