31-01-2025
Climate Change Is Helping Fuel an Urban Rat Boom
From Ratatouille 's Remy to New York's infamous pizza rat, there may be no animal more locked into a love-hate relationship with humans than the genus Rattus. Found on every continent but Antarctica, rats are often seen — with good reason — as a proxy for poverty, filth and disease. And a study published this week in the journal Science Advances suggests that as the climate warms, rat populations are increasing, too.
Milder winters across the Northern Hemisphere are helping rats thrive in ever denser metropolitan areas. Just a handful of warmer weeks a year in a bustling city is enough to boost rodent population growth over time, according to the study.
'That's potentially two to four extra weeks a year that they can be above ground, foraging for food, acquiring those resources that they need to actually reproduce,' said Jonathan Richardson, an assistant professor of biology at the University of Richmond and lead author of the study.
A ballooning rodent population has the potential to create added headaches for public officials already fighting infestations. Rats can damage urban infrastructure and act as a vector for disease. They also take 'a measurable toll' on the mental health of people coexisting with them, according to the study. And there's an economic cost — cities across the globe are already spending $500 million each year to try and keep the rats at bay. In New York, for example, Mayor Eric Adams has declared a ' war on rats,' appointed a rat czar tasked with rodent mitigation efforts and hosted the city's first-ever National Urban Rat Summit.
Urban centers that saw larger increases in temperature over the study periods had larger increases in rat populations, the authors found. Of the 16 cities analyzed, 11 exhibited a growing rat population, including Washington, DC, San Francisco and New York. Population density was another contributing factor to the increase in rodents with denser cities seeing greater growth.
