Extreme Heat Kills

Extreme heat is a killer and this summer has yet again been a season of extreme temperatures. From 1975 to 2004 an estimated extra 1,300 deaths occurred annually, on average, during periods of extreme summer heat. This is a figure that is likely to significantly rise as we experience more and more days of extreme heat.

Last year the New York Times created an animated map to show how extreme heat will spread around the globe during the rest of this century. In How Extreme Heat Could Spread Across the World the NYT has used data from the Climate Impact Lab to shows how 95-degree days (35 degrees Celsius) are expected to multiply this century in countries across the globe.

The NYT's map is based on the world taking moderate action against global warming. Of course if we fail to take action the number of extreme heat days is likely to rise even higher.


The Natural Resources Defense Council has released an interactive map, Extreme Heat, which shows the number of days of extreme heat each year in each U.S. county. Two-thirds of the population are now experiencing many more frequent days of extreme heat than they were just a few decades ago. If you select a state on the NRDC map you can view the number of days of extreme heat each summer and the number of heat related deaths reported in the state in 2005.

The data shown in the map covers the 10 years from 2007 to 2016. So it doesn't even take into account the last two years of record temperatures.


It isn't only Americans who are experiencing more and more days of extreme heat. In 2003 in Europe 70,000 people died during an extreme heatwave. As global warming increases countries around the world are likely to experience many more periods of life threatening extreme heat. By the year 2100 it is estimated that 74% of the world's population will be exposed to deadly heatwaves.

The University of Hawaii has released an interactive map which predicts the number of deadly days we can expect from extreme heat around the world for each year up to 2100. Heatwaves: Number of deadly heat days provides a timeline control which allows you to select any year from 1950-2100. The blue dots on the map show historic extreme heat events that have occurred around the world before 2014.

If you click on the map you can view two charts for the selected location. One chart visualizes the number of yearly deadly days over time and the other shows the humidity vs. temperature for the current year.