erosion and storms. In Canada's Newfoundland and Yukon, sea levels are rising faster than normal.

If conditions continue on the current pathway, glacier and ice sheet melt will raise sea levels by 38 inches by 2100. The most dramatic effects occur in low-lying environments, where even a small rise can inundate a surprisingly large area—for example, about 77 percent of Charleston, South Carolina, could be under water if the sea level rose 12 feet. One in six homes in Boston could be inundated regularly by 2100. The Chesapeake Bay area, with its low shorelines, has persistent and widespread flooding problems; between 1900 and 2017, local sea levels rose about a foot and a half around the Bay.

The situation for residents of South Florida is especially dire. Twelve thousand houses— at least $6.4 billion worth of property—in Miami are in danger of ceaseless flooding by 2050. One of every four people in the United States who will be affected by sea level incursions between 2020 and 2100 lives in Miami-Dade County.

We can expect more frequent high tide flooding, deadly storm surges, and contamination of freshwater aquifers that sustain us. The decisions that we make about living with higher sea levels over the next few years will affect everyone's future. 

Brian Fagan is distinguished emeritus professor of anthropology at the University of California, Santa Barbara. He is the author of several books on ancient climate change, including The Attacking Ocean (Bloomsbury Press, 2014).

Not in My Backyard?

Residents of communities located hundreds or even thousands of miles from the ocean might feel safe from rising coastal waters. But research suggests that many will feel the effects. It is estimated that more than 13 million people in the United States could be displaced by ocean level rise by the end of the century. Their retreat and resettlement into both urban and rural locations could reshape communities in the heart of the country and result in land-use and trade-off conflicts, including, for example, possible sales of public lands for human settlement. Many communities are unprepared for a coastal emigration. "Future migrants will need jobs, houses, and health care," says David Wrathall, an assistant professor in Oregon State University's College of Earth, Ocean, and Atmospheric Sciences and lead author of a policy paper published in Nature Climate Change in November 2019. "Their kids will need schools. The availability of these things will affect where coastal migrants go and their quality of life when they get there."