Mayors from 15 of Florida’s largest cities are calling on Senator Marco Rubio to support measures that address climate change in an open letter sent to the GOP presidential candidate last week.

The state of Florida is especially vulnerable to the effects of climate change including rising sea levels that cause coastal flooding and extreme storms. Areas in the south of the state most threatened by rising sea levels are home to more than $130 billion in real estate as well as two nuclear plants and more than 70 airports. Miami, the state’s second largest city, already faces frequent flooding in city streets.

“Ignoring climate science and doubling down on fossil fuels will only make the climate crisis more rapid and expensive,” the letter reads. “With the presidential election fast approaching, it is critical that your positions on these issues are well informed by the experience of our communities.”

Read More: Obama’s Florida Visit Takes Climate Change Fight to the Front Lines on Earth Day

Rubio, who has gained backing from many in the Republican establishment, has expressed skepticism at instituting policies to address climate change saying that they would hurt the U.S. economy. Asked in Iowa this week point blank whether climate change is “a hoax,” Rubio demurred. “The climate has always changed,” he said. “There’s never been a time when the climate has not been changing.”

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Write to Justin Worland at justin.worland@time.com.