SOURCE: Scientific American

DATE: February 22, 2018

SNIP: The Pacific Coast could see several feet of sea-level rise by the end of this century, and one of its most unique and valuable ecosystems—its salt marshes—may all but disappear in the process.

By the year 2110, all the existing marshland in California and Oregon could be underwater, according to new research in the journal Science Advances. And more than two-thirds of all the wetlands in Washington state could meet the same fate. That’s assuming about 4 feet of sea-level rise by the end of the century—what recent reports predict for the region under moderate to severe future climate change.

Even the marshes that remain won’t be the same as they were before. While today’s wetlands contain a mix of different ecosystems, which are adapted to different conditions, only plants that can tolerate the most frequent flooding—habitats known as “low” marshes—would remain in the future under this scenario.

In some parts of the country, marshes can adjust to sea-level rise by migrating to higher ground, the researchers note. But for most sites along the Pacific coast, it’s a slim possibility. Throughout much of California, the encroachment of cities or agricultural land has left no space for the marshes to move into. And farther north, the coastal landscape becomes too steep for much migration to occur.

“Wetlands won’t migrate up the side of a mountain,” Thorne noted.

That means most of what disappears along the Pacific Coast in the next 100 years will be lost for good.