July 28, 2013 at 5:00 pm
The stories frequently attribute the rising water to “climate change,” which most people believe in but some do not. Whatever the cause, there is no question that the water level in the Chesapeake Bay is getting higher, a combination of the sea rising 3 to 4 millimeters per year and land sinking about 7 millimeters per year. In the past century, sea level rose over 1 foot. Here is what will happen this century to Maryland’s 7,700 miles of coastline.
By Brandon Goldner
Capital News Service
CRISFIELD, MD – Noah Bradshaw knows what the rising waters of the Chesapeake Bay can do to a community.
The 68-year-old city inspector grew up in a house in town that had been moved from nearby Holland Island a century ago.
“Holland Island is gone,” Bradshaw said. “It’s underwater.”
The last house disappeared into the bay two years ago, marking the demise of an island once 5 miles long and home to a fishing community of 300 residents.
Now, rising sea levels and sinking land, the same forces that doomed the island, threaten Crisfield, its seafood industry and its 2,710 residents. And a newly discovered tidal pattern puts them in greater peril than previously known.
“This is our home, and eventually, this will be underwater,” said Bradshaw, a bespectacled, balding man with a white beard. “We know that, because the sea level is rising.”
Scientists say sea levels around the world are rising, that storms are intensifying due to climate change, and that policymakers need to make tough decisions on where to spend limited resources to protect the shoreline and what to let go.
Maryland’s leaders may need to make those difficult choices sooner than other regions.
In his state-of-the-state address this year, Gov. Martin O’Malley warned that Maryland is one of the most vulnerable states in the country to rising sea levels.
Studies show he is right. The Chesapeake Bay is rising at two to three times the rate of worldwide sea levels. It rose more than a foot over the past 100 years and is expected to rise 2 to 5 feet within this century. (See the interactive map at the bottom of the story.)
Property all along Maryland’s meandering shoreline is at risk, from the seaside mansions of Anne Arundel and Talbot counties to the modest cottages of Somerset and Dorchester counties.
Industrial powerhouses like the Port of Baltimore, ecological treasures like Blackwater National Wildlife Refuge and historic sites like the Harriet Tubman monument all lie in the path of rising sea levels.
Lawmakers say they want to protect Maryland’s waterside. But the coastline is 7,700 miles long, according to updated measurements by the Maryland Geological Survey.
That’s twice previous estimates, because of improved aerial imagery and more complete accounting of coastal inlets.
Not all can be saved. And that is a touchy issue in a state where an estimated 900,000 people — a sixth of the state’s population — live in neighborhoods likely to be affected, a CNS analysis of census and U.S. Geological Survey data found.
The state has adopted measures to protect its own property but ceded the tough decisions about the fate of coastal communities to local officials — questions such as whether and when to build sea barriers, elevate land and buildings, or retreat inland.
Plan? What plan?
Yet when researchers interviewed local officials all along the shoreline for a 2010 study, they found “no explicit plan for the fate of most low-lying coast lands as sea level rises.”
Significant resources are likely to be poured into saving property in some of the bigger cities, such as Baltimore and Annapolis. But shore protection is unlikely along 60% of the Eastern Shore, said the study, which was done for the U.S. Environmental Protection Agency.
That Eastern Shore stretch is dotted with rural, poorer and less-populated areas. The Maryland Department of Natural Resources offers communities financial assistance for sea-level rise planning through its federally funded CoastSmart Communities program. Just four of 16 coastal counties and the city of Annapolis have taken advantage of the program in the past five years to develop plans or guidance documents.
Dorchester County, just north of Crisfield, is among the few. Yet local planners “anticipate that most of the county will not be protected from sea level rise” due to “economic difficulties that the county and its residents are experiencing,” the study said.
“Some of the solutions are very costly or very delicate in terms of making decisions about what areas you’re going to protect and what areas you may not be able to protect,” said Zoe Johnson, climate change director for the Maryland Department of Natural Resources.
“There’s a lot of public and social issues with making those decisions. Not many politicians are ready to take that on.”
Combination of rising water and sinking land
The land in the Chesapeake region has been sinking over the past 1,000 to 2,000 years, said Raymond G. Najjar Jr., a Pennsylvania State University oceanographer who has studied the impact of climate change on the mid-Atlantic coast.
Called subsidence, the land has sunk 1.3 millimeters each year on average — a trend scientists say is likely to continue at its current rate.
The rise in sea levels is a relatively new phenomenon and part of a global trend. As the earth warms, polar ice caps melt, the volume of water in the oceans expands, and sea levels rise.
Sea levels worldwide rose on average 4 to 8 inches during the 20th century — but more than a foot in the Chesapeake region.
The rate that sea levels are rising appears to be accelerating, Najjar said. The bay is very likely to rise 2 to 5 feet more by the end of this century, according to his and others’ studies. They also predict more intense storms, bigger water surges during storms, and higher high tides.
CNS analyzed the potential impact, using land elevation data from U.S. Geological Survey and population survey data from the U.S. Census. The effect of local man-made structures, such as seawalls, is difficult to determine and not included in the calculations.
The analysis found that if sea levels rose just 2 feet, water would cover roughly 800 square miles, a 12th of the state, inundating part or all of neighborhoods where nearly 900,000 people live.
At an increase of 5 feet, roughly 1,900 square miles would be underwater, reaching into neighborhoods with about 960,000 people and 440,000 homes worth more than $200 million. An estimated 3,700 miles of roads would be underwater.
Already, more than 13 islands in the bay have disappeared.
On the mainland, high tides alone are enough to prevent charter fishing boats from clearing Fishing Creek Bridge on the western shore — and fill roadside ditches in low-lying areas across the bay, such as Somerset County, where Crisfield is located.
“They have this tradition of working with nature and being able to adapt,” said William Nuckols, who co-authored the 2010 EPA report. “Whether they’re able to work with the increased rate that we’re expecting in terms of the changes they may see, that’s a little more of an uncertainty.”