They're called "ghost forests" — dead trees along vast swaths of coastline invaded by rising seas, something scientists call one of the most visible markers of climate change.
The process has occurred naturally for thousands of years, but it has accelerated in recent decades as polar ice melts and raises sea levels, scientists say, pushing salt water farther inland and killing trees in what used to be thriving freshwater plains.
Efforts are underway worldwide to determine exactly how quickly the creation of ghost forests is increasing. But scientists agree the startling sight of dead trees in once-healthy areas is an easy-to-grasp example of the consequences of climate change.
"I think ghost forests are the most obvious indicator of climate change anywhere on the Eastern coast of the U.S.," said Matthew Kirwan, a professor at Virginia Institute of Marine Science who is studying ghost forests in his state and Maryland. "It was dry, usable land 50 years ago; now it's marshes with dead stumps and dead trees."
It is happening around the world, but researchers say new ghost forests are particularly apparent in North America, with hundreds of thousands of acres of salt-killed trees stretching from Canada down the East Coast, around Florida and over to Texas.
The intruding salt water changes coastal ecosystems, creating marshes where forests used to be.