A pedestrian uses an umbrella to get some relief from the sun as she walks past a sign displaying the temperature on June 20, 2017 in Phoenix. Photo : Getty

The world is gonna get a lot warmer. The unusually warm winter weekend that just ended for those of us in the Northeast is a reminder of what that’ll look like. Sure, it was kinda nice to spend some time outside in a t-shirt in January. But a new study has found that warmer days could be more deadly, even in winter.


The study, published in Nature Medicine Monday, examined how the number of deaths will change in the U.S. where warming is kept to 1.5 degrees Celsius (2.7 degrees Fahrenheit). It found another 1,601 Americans could die a year, not even counting those that are directly heat-related. In a world where the global temperature increases by 2 degrees Celsius (3.6 degrees Fahrenheit)—the level of heating nations agreed to under the Paris Agreement—the number of deaths would rise to 2,135 annually.

The team of scientists behind this study wanted to take a close look at how this all would play out as warmer days become more common, so they ran a model using U.S. mortality and temperature data over 38 years, excluding only Alaska and Hawaii.


They were looking at the impacts of heat beyond heat stroke and dehydration, which are commonly thought of as the drivers of heat-related death and illness. There’s evidence to show that injuries vary by season. For instance, people older than 75 tend to see higher mortality from falls in the winter when ice covers the ground. Also, people tend to drink more when it’s warmer (aka summertime ), and that may contribute to the higher rates of deadly car accidents during this time of year. Higher temperatures have also been linked with higher mortality from assault and suicide, though researchers don’t quite understand why that might be yet.

“We know a lot about the impacts of rising temperatures and climate change on deaths from infectious and non-communicable diseases,” co-author Robbie Parks, a research associate at the Imperial College London’s Department of Epidemiology and Biostatistics, wrote in an email to Earther. “There is a dearth of evidence about how warm temperatures impact injuries. Such injury deaths include suicide, assault, transport accidents, drownings, and falls. Since deaths from injuries are seasonal, it was a natural next step to investigate whether temperature might have a role in the variations in injury death rates both within a year and between equivalent times in different years.”

The team came to its conclusions after using a model that looked at how each state’s number of injury deaths between 1980 and 2017 fluctuated in coordination with temperature. The researchers used the long-term temperature average as a marker for what’s “unusual,” per the study.


Most deaths in the 1.5-degree scenario would be from “transport injuries,” which include accidents from any roadway vehicle, as well as flights, boats, and trains. Suicide, unfortunately, comes in a close second for the highest number of deaths. Eighty-four percent of these additional suicide deaths would affect men who traditionally have higher suicide rates than women. More Americans are also expected to drown in this world where the world warms only 1.5 degrees Celsius as more people flock to the water for a swim in a hotter future.

Yes, even the leisure activities to beat the heat could end up killing people. The study reveals a whole host of new problems that come with a warming world that policymakers will need to consider and decide how they want to prevent more unnecessary deaths from happening. They can build out protections to keep Americans safer when things get real. Especially because the 1.5-degree best case scenario is feeling real unlikely these days.


“These results could have an influence on policy for climate change and health now and into the future,” Parks wrote in the email. “For example, investing in better public transport can have a co-benefit of improving city connectivity, reducing air pollution from private transport, while also reducing the number of potential incidences of driving accidents in times of warmer temperatures.”

This will be especially important for individuals who already live in warm climates. This study looks only at U.S. Imagine what this may look like for African nations or those in the Middle East.