Dartmouth Researchers: Global Warming Leading to More Home Runs in MLB
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Endangered species and coastal cities are far from the only victims of so-called climate change. According to a Dartmouth study, the pitchers of Major League Baseball are now falling victim to the scourge of global warming.

According to a study published on Friday, the Dartmouth team claims that at least 500 major league home runs over the past decade can be directly attributed to global warming. The researchers further claim that several hundred additional round-trippers per season will be caused by global warming.

“We show that global warming has increased home runs in baseball by reducing game time air density. Without gameplay adaptations, future warming will intensify this effect alongside other climate impacts,” the study states.

The study’s authors claim to have studied more than 100,000 Major League Baseball games between 1962 and 2019. Going even more in depth, the authors investigated more than 220,000 individually batted balls from 2015-2019.

“The result from this framework is a plausibly causal estimate of the effect of an increase in temperature on the number of home runs hit in each game,” the study states.

With 95 percent confidence, the authors conclude, “A 1-°C increase in the daily high temperature on the day of a baseball game played in a stadium without a dome increases the number of home runs in that game by 1.96%.”

While the researchers acknowledge that there may be multiple reasons for the uptick in home runs since 1980, they claim that one major factor for the increase in home runs is global warming.

“Those other factors are definitely more responsible as of now than global warming,” said Christopher Callahan, a doctoral student who worked on the study. “Certainly the analytics revolution has played a major role.”

“We say that climate change has caused about 500 more home runs over the past 10 years but that’s only about 1 percent of home runs,” Callahan said.

However, with “all else being equal, warmer air is less dense and a batted ball will carry farther,” the paper claims. “Air density is inversely proportional to temperature.”

Ballparks expected to be most affected by climate change are outdoor parks with a high percentage of day games, such as Chicago’s Wrigley Field.

“Places like Wrigley Field will see a lot more home runs in the future, because it’s open air and a lot of games are played in the daytime,” the authors claim. “And so you get a ton of more [global warming assisted] home runs there, but you’ll get a lot fewer in places where there are domes and the games are more frequently played in the evening to start with.”

Of course, with the study focusing only on the major leagues, it neglects other organizations that play baseball at a less-elite level.

As Dr. Roger Pielke points out, “There is an obvious control group, AAA baseball (completely ignored in this new paper).”

Home runs in MLB are, admittedly, up over the last several years — 4,186 homers were hit in MLB in 2014 spiking up to 6,776 in 2019. 2019 seemed to be the high point, with only 5,215 homers being hit last year. Interestingly, 2016 — the year climate hysterics continue to tell us was the warmest year on record — only yielded 5,610 home runs.

But home runs in other baseball organizations don’t appear to be much affected by global warming. Watts Up With That points out that in AAA baseball, the MLB’s feeder organization, home runs are decidedly down. In Japan’s national professional league, the NPB, home runs are essentially static — neither up or down — over the decades.

And in Division One college athletics, home runs appear to be trending downward as well.

So, the good news is that climate change is only affecting baseball at the very highest levels. Climate change or not, the game appears unaffected regarding home run quantity in college or other professional organizations. Global warming is only attacking the major leagues.