America's largest cities are at the forefront of climate change.
About 80% of the U.S. population live in urban settings, according to the U.S. Census Bureau. Some of the country's most densely populated cities, like New York City, are already at the frontlines of global warming, according to experts.
"This particular section of the population is very vulnerable to a range of climate impacts," Rachel Cleetus, policy director for the Climate and Energy Program at the Union of Concerned Scientists, told ABC News.
Heat is one of the two major impacts expected to plague cities as climate change continues to worsen, the experts told ABC News.
"Extreme heat is one of the most clearly recognized signals of climate change," Cleetus said.
One of the biggest concerns for residents of large cities when a heat wave arrives are for those living in disadvantaged communities who do not have access to air conditioning or can not afford to run it all the time, Madajewicz said.