Coastal erosion

Wetlands have flourished along the world’s coastlines for thousands of years, playing valuable roles in the lives of people and wildlife. They protect the land from storm surge, stop seawater from contaminating drinking water supplies, and create habitat for birds, fish and threatened species. Much of that may be gone in a matter of decades. As the planet warms, sea level rises at an ever-faster rate. Wetlands have generally kept pace by building upward and creeping inland a few meters per year. But raised roadbeds, cities, farms and increasing land elevation can leave wetlands with nowhere to go. Sea-level rise projections for midcentury suggest the waterline will be shifting 15 to 100 times faster than wetland migration has been clocked. Many wetlands, like these on Cape Cod, are now bordered by human infrastructure, including towns and roads. Lance Cheung/USDA I have been studying coastal g...

Honolulu has lost more than 5 miles of its famous beaches to sea level rise and storm surges. Sunny-day flooding during high tides makes many city roads impassable, and water mains for the public drinking water system are corroding from saltwater because of sea level rise. The damage has left the city and county spending millions of dollars on repairs and infrastructure to try to adapt to the rising risks. Future costs will almost certainly be higher. More than US$19 billion in property value, at today’s dollars, is at risk by 2100 from projected sea level rise, driven by greenhouse gas emissions largely from the burning of fossil fuels. Elsewhere in Honolulu County, which covers all of Oahu, many coastal communities will be cut off or uninhabitable. Unwilling to have their taxpayers bear the full brunt of these costs, the city and county sued Sunoco LP, Exxon Mobil Corp. and other big oil companies in 2020. Their case – one of more than two dozen involving U.S. ci...

Back-to-back hurricanes left an unnerving scene on the Florida coast in November 2022: Several houses, and even swimming pools, were left dangling over the ocean as waves eroded the property beneath them. Dozens of homes and condo buildings in the Daytona Beach area were deemed unsafe. The destruction has raised a disturbing question: How much property along the rest of the Florida coast is at risk of collapse, and can it be saved? As the director of iAdapt, the International Center for Adaptation Planning and Design at the University of Florida, I have been studying climate adaptation issues for the last two decades to help answer these questions. Drone footage shows homes close to collapsing into the ocean. WPLG/YouTube. Rising seas, aging buildings Living by the sea has a strong appeal in Florida – beautiful beaches, ocean views, and often pleasant breezes. However, there are also risks, and they are exacerbated by climate chang...

The powerful remnants of Typhoon Merbok pounded Alaska’s western coast on Sept. 17, 2022, pushing homes off their foundations and tearing apart protective berms as water flooded communities. Storms aren’t unusual here, but Merbok built up over unusually warm water. Its waves reached 50 feet over the Bering Sea, and its storm surge sent water levels into communities at near record highs along with near hurricane-force winds. Merbok also hit during the fall subsistence harvest season, when the region’s Indigenous communities are stocking up food for the winter. Rick Thoman, a climate scientist at the University of Alaska Fairbanks, explained why the storm was unusual and the impact it’s having on coastal Alaskans. What stands out the most about this storm? It isn’t unusual for typhoons to affect some portion of Alaska, typically in the fall, but Merbok was different. It formed in a part of the Pacific, far east of Japan, where historically few ty...

Centuries ago, estuaries around the world were teeming with birds and turbulent with schools of fish, their marshlands and endless tracts of channels melting into the gray-blue horizon. Fast-forward to today, and in estuaries such as New York Harbor, San Francisco Bay and Miami’s Biscayne Bay – areas where rivers meet the sea – 80% to 90% of this habitat has been built over. The result has been the environmental collapse of estuary habitats and the loss of buffer zones that helped protect cities from storm surge and sea-level rise. But the damage isn’t just what’s visible on land. Below the surface of many of the remaining waterways, another form of urbanization has been slowly increasing the vulnerability of coastlines to extreme storms and sea-level rise: Vast dredging and engineering projects have more than doubled the depths of shipping channels since the 19th century. Side-by-side illustrations sho...