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Coastal squeeze, or the collision between coastal development and rising seas, poses a threat to beaches, and the public's ability to enjoy and access them. David Ramos/Getty Images
As Americans flock to beaches this summer, their toes are sinking into some of the most hotly contested real estate in the United States.
It wasn't always this way. Through the mid-20th century, when the U.S. population was smaller and the coast was still something of a frontier in many states, laissez-faire and absentee coastal landowners tolerated people crossing their beachfront property. Now, however, the coast has filled up. Property owners are much more inclined to seek to exclude an ever-growing population of beachgoers seeking access to less and less beach.