PHILADELPHIA (CBS) — Philadelphia is considered a coastal city, since its waterways, like the Delaware River, are tidal. And a new report from the National Wildlife Federation shows rising sea levels will threaten the city in the coming years.

The report shows every city on the east coast will suffer, and Philadelphia could see significant flooding. Ed Perry is with the National Wildlife Federation and said they are trying to think ahead.

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“Already, sea level is up about a foot in Philadelphia. And within the next 50 to 75 years, it’s expected to rise another five feet,” Perry said.

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A map depicting the results of that rise shows the airport, the John Heinz National Wildlife Refuge and much of South Philadelphia could end up under water. Perry said the only answer is to reduce carbon pollution. There are two main methods:

“Put a restriction on the amount of carbon that can come out of power plants, or to put a fee on the major sources of carbon pollution, that’s cars and light trucks and power plants.”

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Perry recommends residents encourage their elected representatives to pass laws that will help stop global warming.