By Tracy J. Wholf, Cara Tabachnick
Urban dwellers in Washington D.C., San Francisco, Toronto, New York City, and Amsterdam might have seen rats scurrying across their cities — and they’re not imagining an influx.
Rat populations have spiked in cities with warming temperatures resulting from climate change or urban heat islands, found a study released Friday in the journal Science Advances. Researchers analyzed public complaint and inspection data in 16 cities worldwide to estimate trends in rat populations and connect it to global warming patterns — marking the first time these associations have been linked.
“We found these cities that have increasing warming trends over the last 50 years or so also have faster number of rats,” Jonathan L. Richardson, an associate professor at the University of Richmond and lead study author, told CBS News.
Richardson’s lab tracks rats across the globe and his team conducted research in 16 cities including Oakland, Buffalo, Chicago, Boston, Kansas City, and Cincinnati for the study. Of the 16 cities analyzed 11 cities had “significant” increases in rat populations, while just three cities – Tokyo, Louisville, and New Orleans — had declining populations.