Taking to social media to complain about hot subway rides? You’re not alone, study says

Commuters, residents, and tourists who take to social media during warm months to complain about sweltering subway systems in New York, Boston, and London should feel vindicated—new research says they aren't alone. As temperatures rise aboveground, the number of subway riders reporting uncomfortable heat belowground increases, according to a new study in the journal Nature Cities. This could worsen as climate change, driven by the burning of fossil fuels, makes for a hotter planet. Northwestern University researchers analyzed more than 85,000 crowdsourced social posts on the social platform X and Google Maps reviews from 2008 to 2024 in those three major cities’ subway systems. They searched for keywords related to being too hot—or what they called “thermal discomfort”—in those metropolises, which are some of the world’s oldest and busiest. The experts looked for terms such as “hot” and “warm” while filtering out results that did not seem to relate to temperature, such as “hot dog.” The study’s authors said subway riders may expect temperatures to be naturally cooler underground. They found that a 1°F (0.5°C) increase in outdoor temperature led to a 10% increase in complaints in Boston, 12% in New York, and 27% in London. Earth’s average temperature warmed 1°F (0.56°C) from 2008 to 2024, according to the National Oceanic and Atmospheric Administration. The researchers analyzed posts across seasons, time of day, and day of week. “Interestingly, over the weekend, people complained less,” said Giorgia Chinazzo, assistant professor in Northwestern’s Department of Civil and Environmental Engineering, who co-authored the study with associate professor Alessandro Rotta Loria. Chinazzo speculated that one reason may be that people were dressing differently than on workdays. Flavio Lehner, an assistant professor of Earth and atmospheric sciences at Cornell University who was not involved in the work, said the research “follows the template of previous studies that link environmental conditions to human behavior using social media data.” He has also studied how warm conditions trigger a stronger online reaction. Lehner said limitations of the research include only monitoring three city transit systems and it being difficult to control for other factors influencing social media behavior. This article was provided by The Associated Press.