Octavio Castillo paddles a boat down a flooded street to reach the home of his cousin on April 19, 2013, in Des Plaines, Ill. (Scott Olson/Getty Images)

On April 18, 2013, Illinois Governor Pat Quinn (D) declared a state of emergency after an epic deluge left much of the Chicago area under water.

“After several days of rain, an overnight deluge overwhelmed Chicago’s underground labyrinth of aging sewers and giant tunnels Thursday, forcing a noxious mix of sewage and stormwater into local waterways and Lake Michigan. The surge of murky, debris-strewn water so overloaded the system that sewage began to back up in basements and geysers of wastewater shot out of several sewer manholes,” the Chicago Tribune reported.

“The only way to get around is by kayak or canoe,” one resident told a local CBS affiliateMajor roads disappeared under water. Some residents had to evacuate their homes. A massive sinkhole swallowed three cars after the intense rain caused a water main to break.

“This is a new kind of storm associated with climate change,” Tom LaPorte, spokesman for the Chicago Department of Water Management, told Medill Reports on day two of the April flood. Extreme flooding is part of a pattern that has emerged in the last two decades, according to Illinois State climatologist Jim Angel.

Now a major insurance company is suing Chicago-area municipal governments saying they knew of the risks posed by climate change and should have been better prepared. The class-action lawsuits raise the question of who is liable for the costs of global warming.

Filed by Farmers Insurance Co. on behalf of itself, other insurance companies and customers whose property was damaged by the surge of storm water and sewage overflow, the lawsuits allege the governments of Chicago-area municipalities knew their drainage systems were inadequate and failed to take reasonable action to prevent flooding of insured properties.

“During the past 40 years, climate change in Cook County has caused rains to be of greater volume, greater intensity and greater duration than pre-1970 rainfall history evidenced,” a fact that local governments were well aware of, a suit filed in Cook County, Ill., alleges, citing a climate change action plan adopted in 2008 that acknowledges the link between climate change and increased rainfall.

The suits also say the localities knew their drainage systems weren’t up to snuff because the regional water management authority had published plans in 2011 detailing various defects.

Knowing the risks, they argue, local governments should have increased their storm water storage capacity. Furthermore, the suits allege they were negligent in failing to take temporary measures in the days before the storm, such as deploying water-inflatable property protection systems to mitigate damage.

These lawsuits are the first of their kind, Michael Gerrard, director of the Center for Climate Change Law at Columbia Law School in New York, told Reuters. Gerrard said he expects to see more like them.

“I think what the insurers are saying is: ‘We’re in the business of covering unforeseen risks. Things that are basically accidents,’” Ceres insurance industry analyst Andrew Logan told NPR. “‘But we’re now at a point with the science where climate change is now a foreseeable risk.’”

The insurance companies are in for an uphill battle. Daniel Jasica of the State’s Attorney’s Office in Lake County, which is named in the Illinois state court suit, told Reuters that the localities will claim government immunity protects them from prosecution.

“Even if a city is likely to win a lawsuit, it still is going to have to spend quite a bit in defending itself,” Robert Verchick, who teaches environmental law at Loyola University in New Orleans, told NPR. “And it might just be better for everybody involved for cities to take climate change seriously.”