Climate change is contributing to a global rise in urban rat infestations, according to a study published by Science Advances in January.
As temperatures increase, rats are better able to thrive — even in inclement weather that would typically deter the population’s growth, according to the article.
Temperatures in urban settings have been projected to rise between 1.9 degrees and 4.4 degrees by the year 2100 due to greenhouse gas emissions, according to the study.
“So we imagine it probably increases their survival over the winter. And we’re pretty sure that that increased food intake also will lead to more reproductive bouts for these rats, which can accelerate population growth,” Jonathan Richardson, the study’s lead author and professor of biology at University of Richmond, told ABC News.
The study, which examined public complaint and inspection data in 16 cities worldwide, found that most places had increased rat growth trends. Some places are managing the “ratpocalypse” better than others, the study found.
In Washington, D.C., for example, the rat population is growing 1.5 times faster than it is in New York City, because the more northerly city has taken notable steps to keep rodents in check. In New Orleans and Tokyo – two cities with robust rodent response teams and good citizen reporting systems – the rat populations appear to be shrinking.
Richardson said that cities experiencing declines might be outliers, rather than part of a broader trend, though he did note that in Tokyo, residents seem willing to post rat sightings on social media in a “name and shame” approach to getting businesses to clean up their act.