Models predict climate change responsible for thousands of additional deaths by 2095

By 2095, compared with the year 2000, an additional 21,000 deaths attributable to increases in particulate matter less than 2.5 micrometers in diameter may occur in the United States, a recent model showed.

A second model predicted that increases in ozone levels between the years 2000 and 2095 could cause approximately 4,100 more U.S. deaths.

Neal L. Fann, MPP, a team leader within the Office of Air Quality Planning and Standards at the U.S. Environmental Protection Agency, and colleagues wrote their findings “suggest that reducing air pollutant emissions could attenuate but not eliminate the climate change-induced increase in mortality associated with air pollution.”

The researchers used abated versions of high warming scenarios from global climate models known as Community Earth System Model (CESM) and the Coupled Model version 3 (CM3). They also utilized a chemical transport model to estimate particulate matter less than 2.5 micrometers in diameter (PM_2.5) and ozone (O₃) concentrations under a 2011 air pollutant emission data set and a 2040 projection, as well as census data from several different years during the 21st century.

“To the extent that these risks are sensitive to meteorologically influenced behavioral variables (such as air conditioning use), then using these parameters to estimate future changes in risk may underestimate or overestimate impacts,” Fann and colleagues wrote.

The researchers found that by 2095, and compared with 2000, an estimated 21,000 (95% CI, 14,000–28,000) additional deaths attributable to PM_2.5 and 4,100 (95% CI, 2,200–6,000) additional deaths linked to O₃ under each climate model could occur. The relative number of avoidable premature deaths associated with climate-driven changes varied by region of the United States. In addition, projections dropped to an estimated 15,000 (95% CI, 10,000–20,000) additional deaths attributable to PM_2.5 and 640 (95% CI, 340–940) additional deaths link to O₃ when a future emission inventory that accounted for reduced anthropogenic emissions was used.

In a related editorial, Patrick Kinney, ScD, professor of environmental health at the Boston University School of Public Health, said there are “substantial uncertainties” with the models that were used in the study, but the findings still play a “critical role in helping society to anticipate, prepare for and ideally mitigate adverse health impacts of our rapidly changing climate.”

“Although it is encouraging that the potential health benefits that Fann et al show could be attained by implementing the regulations already on the books through 2040, we will need to do even more to reduce air pollution-attributed health impacts even further while also addressing the looming climate crisis,” he wrote.

References:

• Fann NL, et al. JAMA Netw Open. 2021;doi:10.1001/jamanetworkopen.2020.32064.
• Kinney P. JAMA Netw Open. 2021;doi:10.1001/jamanetworkopen.2020.35010.