While President Trump still denies climate change, warmer weather is fueling a rodent surge in his own country. 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 heavens.
—rats are experiencing a baby boom. The rats have taken advantage of these condition to squeeze out one more litter, resulting in exploding numbers.
One more 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: 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 study showed that New York City’s rats carry diseases like E. coli, salmonella and Seoul Hanta Virus. Rats also carry the bacteria that causes leptospirosis, which recently killed one person and sickened two in the Bronx.
No one really knows how many rats there are. Not in New York City, nor Washington, DC, nor Chicago—all three of which rank among the most rodent-infested cities in the U.S.
 Holthaus: It’s Official: This Was America’s Warmest Winter on Record in The Slatest – 08 March 2016. See here.
 New York rats carry some pretty scary diseases in Washinton Post – 21 October 2014. See here.
 This rare disease spreads through contact with rat urine. In New York, it has left 1 dead in Washington Post – 15 February 2017. See here.