Most cities know rat woes well. Washington, D.C., for instance, has burned through countless plans to stymie its longstanding “rat problem” or “rodent crisis,” in which disease-ridden critters are not only growing in number but ballooning to the size of human infants.
What they don’t know is how this all will end. Houston, Texas, is seeing a rat spike this year, and so is New York City. In Chicago, rodent complaints for the early part of the summer have increased about 9 percent from last year, forcing city officials to start sprinkling the streets with rat birth control. Philadelphia and Boston were recently ranked the two cities with the most rat sightings in the country. And it’s not just this year; as USA Today reported last year, major cities saw spikes in rodent-related business from 2013 to 2015. Calls to Orkin, the pest control service, were reportedly “up 61 percent in Chicago; 67 percent in Boston; 174 percent in San Francisco; 129 percent in New York City; and 57 percent in Washington, D.C.”
It’s no surprise that rats thrive in cities, where humans provide an abundance of food and shelter. But experts now agree that the weather is playing a role in these recent increases. Extreme summer heat and this past winter’s mild temperatures have created urban rat utopias.
“The reason the rats are so bad now, we believe, is because of the warm winters,” said Gerard Brown, program manager of the Rodent and Vector Control Division of the D.C. Department of Health, at a 2016 rat summit.
Rat pro Corrigan agrees. “Breeding usually slows down during the winter months,” he said. But with shorter, warmer winters becoming more common—2016 was America’s warmest winter on record—rats are experiencing a baby boom. “They have an edge of squeezing out one more litter, one more half litter,” Corrigan said.
One more litter or half litter makes a serious difference when a population boom is not only a nuisance, but a public health and economic crisis. Rats breed like rabbits; as this alarming Rentokil graphic shows, two rats in an ideal environment can turn into 482 million rats over a period of three years. Urban rats caused $19 billion worth of economic damage in the year 2000, partially due to the fact that they eat away at buildings and other infrastructure. Imagine how much they’re costing now.
What’s more, every new litter increases the risk of a rodent-borne disease. A 2014 Columbia University study showed that New York City’s rats carry diseases like E. coli, salmonella, and Seoul hantavirus, which “can cause Ebolalike hemorrhagic fever,” according to the Washington Post. Rats also carry the rare bacterial disease known as leptospirosis, which recently killed one person and sickened two in the Bronx.
Clearly, the coming ratpocalypse is no longer a city-centric problem. It is threatening the health of millions across the country, costing billions of dollars, and is being fueled by global climate change that the U.S. primarily created. And yet cities—which are expected to hold 70 percent of the world’s population by 2050—are largely dealing with their rodent crises on their own. Why isn’t the federal government stepping in?