Deaths by suicides, assaults, transport accidents, drownings and falls were forecast to be on the up if temperatures rose on average by 1.5 and 2 degrees Celsius above pre-industrial levels, the authors of the paper published in the journal Nature Medicine found.

The researchers analyzed data on deaths and temperatures between 1980 to 2017 in mainland United States, excluding Alaska and Hawaii, to see if anything changed when the weather was 1.5 and 2 degrees Celsius higher than average. They chose these figures as the international Paris Agreement on the climate, which the U.S. has started the process of withdrawing from, aims to keep average post-industrial global temperatures well below 2 degrees Celsius, and preferably to 1.5 degrees Celsius.

A spike of 1.5 degrees Celsius was linked to an annual estimated 1,601 additional deaths as a result of injuries across the country, while a rise of over at least 2 degrees Celsuis was linked to 2,135 extra deaths per year.

In a commentary on the paper also published in the journal Nature Medicine, a pair of scientists not involved in the study wrote that it is important to note that other variables of weather which are linked to injuries like rain, humidity, sunshine, and wind “may act in their own right while also interacting with temperature, although not necessarily in consistent or predictable fashions.”

More research is needed to see which locations and populations would be most affected, pointing to previous research identifying people who are poor or African-American, living in coastal and low-lying areas, or work outdoors are more vulnerable to the health effects linked to climate change.

Study co-author Robbie Parks of the department of epidemiology and biostatistics at Imperial College told Newsweek a lot is known about the impacts of rising temperatures and climate change on deaths from infectious and non-communicable diseases. But less is known about how warm temperatures impact injuries.

Parks said he was “particularly surprised at how consistent the association between anomalously warm temperatures and suicide/assault deaths.”

He said: “One might label increasing numbers of injury deaths from rising temperatures as a hidden public health burden of climate change.”

Asked what underlies the findings, he said: “drownings are plausibly linked with anomalously warm temperatures because swimming is more likely in periods of warm weather. Transport accidents are also linked because driving performance deteriorates at higher temperatures, due to decreased visual acuity as well as increased alcohol consumption.

“Increases in assaults may be due to increasing anger levels and more time spent outdoors interacting with other people during warmer weather. Reasons for increased suicide deaths are not well-established and warrant further investigation,” he said. Parks urged people to be considerate of others during hot weather. “Someone who appears to be OK (at least physically) may not actually be. They may be suffering on the inside,” he said.

“So, look out for and check in on each other, build a sense of community wherever you are! It could make a difference to someone’s health and well-being, both inside and out.”

Chiming with the authors of the commentary, Parks said it would have been interesting to investigate the impacts by country “as variations in risk may be due to local variations in socioeconomic and environmental factors, as well as infrastructure or health and social services available.”

Parks said he hopes the work will shape policies responding to climate change. “Anomalous temperatures are occurring all the time, with varying warm anomalies evident throughout most years, especially recently,” he said. “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.”

He added: “The need for climate change mitigation underpins all of this action, and large-scale structural changes will provide that opportunity for mitigation, while also reducing the vulnerability of particular groups to injury deaths.”

Additional deaths which may be caused by a 2 degree Celsius by state, (rounded to the nearest 5)

Alabama 55 Arizona 55 Arkansas 30 California 230 Colorado 40 Connecticut 15 Delaware 5 District of Columbia 5 Florida 160 Georgia 80 Idaho 15 Illinois 75 Indiana 50 Iowa 20 Kansas 25 Kentucky 40 Louisiana 50 Maine 10 Maryland 35 Massachusetts 20 Michigan 60 Minnesota 20 Mississippi 35 Missouri 55 Montana 10 Nebraska 10 Nevada 25 New Hampshire 5 New Jersey 35 New Mexico 20 New York 65 North Carolina 75 North Dakota 5 Ohio 70 Oklahoma 35 Oregon 25 Pennsylvania 70 Rhode Island 5 South Carolina 50 South Dakota 5 Tennessee 55 Texas 205 Utah 20 Vermont 5 Virginia 45 Washington 40 West Virginia 15 Wisconsin 30 Wyoming 5