The essay below 
The Conversation, an online publication covering the latest research.
Home runs are exhilarating – everyone is looking up at the sky and baseball players and fans alike are waiting for the result.
The number of home runs in Major League Baseball has increased dramatically over the last few seasons, and Aaron Judge’s record-breaking 62 home runs for the New York Yankees in 2022 is an example.
Baseball analysts point to a variety of factors for this surge, from changes in baseball structure to advances in game analysis.
Our new study, published on April 7, 2023, provides solid evidence for another cause: global warming.
What I learned from 100,000 baseball games
Physics tells a simple and compelling story. Warm air is less dense than cold air. As the air heats up and the molecules move faster, it expands, creating spaces between the molecules. As a result, the ball should travel farther in warm weather than in cold weather because there is less air resistance.
This simple physical link has sparked media speculation about the link between climate change and home runs.
But while scientists like Alan Nathan have shown that balls fly farther at higher temperatures, there’s no formal science proving that global warming is fueling baseball’s home run momentum. No research has ever been conducted.
Our study, published in the Proceedings of the Meteorological Society of America in collaboration with anthropologists (and baseball fans) Nathaniel J. Dominy and Jeremy M. DeSilva, found that over 100,000 major league baseball games and 200,000 individual batted balls Using data from and observed gameday temperatures, it is shown that the increased temperature actually increased the number of home runs.
Based on data from 1962 to 2019, when Mickey Mantle was the American League MVP and Willie Mays was the top of the home run chart, in a game 10 degrees Celsius (18 degrees Fahrenheit) higher than the average game, the average I found it to be nearly 20% hotter than a typical match. More home runs than average.
So what about all the other things that drive home runs?
It is not possible to play a cast of pitches from the 1960s onwards and run a controlled experiment in which only temperature is varied to assess the effect on home runs. However, with the large amount of data on home runs and temperature, we can statistically estimate its impact. Whether a game is hotter or colder than average has nothing to do with other home run-promoting factors, such as ball construction, steroid abuse, game analysis, or height differences between ballparks. This fact allows us to statistically separate the role of temperature.
To validate the game-level model, we use data from high-speed cameras that have been installed in ballparks since 2015. The camera provides the firing angle and rate of fire for each hit. Of which he had 200,000 included in the survey. This means that you can compare the ball falling from the bat at the same angle and speed on warm and cold days. This is an almost perfect experimental condition.
The high-speed camera model almost exactly reproduced the effect of temperature on home runs estimated in the game-level data. Taking advantage of this observed relationship between game-day temperatures and home runs, experiments from climate models can be used to estimate how many home runs have been hit so far because of climate change. I made it.
More than 500 home runs since 2010 could be directly related to a reduction in atmospheric density due to human-induced global warming, the study found.
More home runs in a warm future
The same approach can be used to estimate future home runs.
For example, if the world continues to emit large amounts of greenhouse gases, temperatures will continue to rise and could soon hit hundreds of home runs a year. Thousands of home runs could be hit over the course of the 21st century.
The team has a way of fighting the heat. For example, you can change a daytime game to night or build a dome over a ballpark. In Denver, where the high altitude makes the air less dense, the Rocky Mountains began storing game balls in humidors in 2002 to increase the weight of the sphere and give pitchers more sporting opportunities.
not all high fives
Rising home run numbers may sound exciting, but they are also a visible sign of a much bigger problem facing sports and people around the world as the planet warms.
Rising temperatures threaten the health and safety of baseball players, ballpark fans, and people around the world. Without serious efforts to reduce greenhouse gas emissions, rising temperatures will transform nearly every aspect of society, from cultural touchstones like baseball to basic human well-being. put away.
This article originally appeared on The Conversation. Please read the original article.
