Climate change could be leading to more home runs, finds new study

"All else being equal, warmer air is less dense, and a batted ball will carry farther," the study further noted.

This is not the first time a correlation between temperatures and ball trajectories has been proposed. During a 2021 broadcast, the late Tim McCarver, a major-league catch, stated that climate change could be impacting the long ball by "making the air thin." 

Unlike the new study, the comment was not well received at the time with the sports website Deadspin calling the theory "one of the stupidest things ever spoken on a television broadcast."

Plausible indeed

Today, however scientists are much more open to the possibility.

Dr. Jonathan Martin, a professor in the department of atmospheric and oceanic sciences at the University of Wisconsin-Madison, told Newsweek that the results of the study seem plausible.

"I think I would say that warming and the associated density decrease in the air is a factor, but not likely the leading factor," Martin said. "Consider that another attendant change with global warming is increased humidity. Though moist air is even less dense than dry air—furthering the author's basic proposition—more humidity also carries physiological impacts on the players. Namely, it reduces physical efficiency."

The study was published in the journal Bulletin of the American Meteorological Society.

Study abstract:

Home runs in baseball—fair balls hit out of the field of play—have risen since 1980, driving strategic shifts in gameplay. Myriad factors likely account for these trends, with some speculating that global warming has contributed via a reduction in ballpark air density. Here we use observations from 100,000 Major League Baseball games and 220,000 individual batted balls to show that higher temperatures substantially increase home runs. We isolate human-caused warming with climate models, finding that >500 home runs since 2010 are attributable to historical warming. Several hundred additional home runs per season are projected due to future warming. Adaptations such as building domes on stadiums or shifting day games to night games reduce temperature’s effects on America’s pastime. Our results highlight the myriad ways that a warmer planet will restructure our lives, livelihoods, and recreation, some quantifiable and easily adapted to, as shown here, many others, not.