The Chesapeake Bay is rising. Since Captain John Smith settled Jamestown, Va., near the shores of the Chesapeake in the 1600s, the bay has risen 0.9 meters (three feet). This rise in sea level has drowned many islands where small fishing communities once thrived.
By the end of this century, the Chesapeake could rise an additional 0.6 meters (two feet), according to moderate estimates reported by an organization called CSSPAR (pronounced “see-spar”), which stands for Chesapeake Sea Level Rise and Storm Surge: Public Awareness and Response. This partnership, which includes the National Geographic Society, was started by the Conservation Fund. CSSPAR works to gather and distribute information about sea level rise and intensified storm surges on the Chesapeake Bay.
Polar ice from both Greenland and Antarctica is melting into the world’s oceans. Oceans rise at an average rate of six inches every 100 years.
Sea level in the Chesapeake Bay rises at a faster rate than average because the land underneath the bay is sinking. During the last ice age, glaciers pushed the land surrounding the Chesapeake Bay upward. After the glaciers melted, the land slowly retreated to its original position through a process called land subsidence. As the land sinks, the water in the Chesapeake Bay rises. Land subsidence contributes to about half of the Chesapeake region’s observed sea level rise. Melting ice causes the remainder.
The Nation’s Estuary
Since so much of the land in the Chesapeake region already lies very near sea level, even a small rise would have a huge impact.
“If an area of land is less than 0.6 meters (two feet) above sea level, and connected to a stream or inlet that is part of the bay, than that area is at risk for what we call ‘inundation’ by rising sea,” explained Sean O’Connor, a National Geographic Society cartographic researcher.
O’Connor created maps for CSSPAR that illustrate the predicted effects of sea level rise on the Chesapeake Bay. If sea level rise continues on its current path, the bay would invade the land for miles in some places, destroying 167,000 acres of marshland and three million people’s homes by the year 2100.
The Chesapeake Bay is a precious American resource, “the nation’s estuary,” as O’Connor describes it.
The U.S. capital, Washington, D.C., sits upon the Chesapeake watershed. An estuary is an ecosystem where fresh river water pours into the salty ocean, creating a delicate, marshy habitat. Hundreds of rivers empty into the Chesapeake estuary along the shorelines of six states. Around 20 million people live in the Chesapeake region.
“The shorelines of the Chesapeake are flanked with important human infrastructure, like the naval facilities at Norfolk, Va., or the bustling commercial, residential, and tourist districts of Baltimore, Md. And much more area is graced with low-lying wetlands, cypress forests and tidal marshes that are home to countless species of fish, mammals, birds and more. But yet, the estuary finds itself under constant threat of dying out from too much pollution, from overharvesting of species and now from climate change,” O’Connor said.
Sea level rise in the Chesapeake Bay will destroy the wetland habitats of many birds, fish, shellfish and plants. Human populations and structures are also at risk. In many low-lying areas, farms and homes will have to be relocated as the bay floods the land. Roads, bridges and buildings will need to be removed and restructured, as will sewage, draining and other utility systems. As the sea creeps inland, rebuilding the infrastructure of major metropolitan areas such as Baltimore will be an extremely costly endeavor.
Storms Are Brewing
The more acute devastation of sea level rise will threaten the area when storms hit. The region’s cities will be flooded as the ocean surges inland.
A higher water level in the bay means stronger storm surges and higher floodwaters. The warm waters of the Atlantic Ocean can thrust powerful tropical storms and hurricanes into the U.S. East Coast, and the low-lying Chesapeake region is vulnerable when one of these storms hits. As global warming intensifies, these storms will become more powerful and more frequent.
More intense storm surges are already hitting the Chesapeake. Scientists from CSSPAR compared data from a 1933 storm (the Chesapeake-Potomac Hurricane) to data from a 2003 storm, Hurricane Isabel. The storms hit the same coastal area with approximately equal force. However, the storm surge from Isabel was about a foot higher than the one in 1933.
Hurricane Isabel's surge was measured at 0.9 to 1.5 meters (three to five feet) above the normal water levels of the Chesapeake Bay. In the Maryland cities of Baltimore and Annapolis, water was 1.8 to 2.4 meters (six to eight feet) higher than normal.
The deadly storm ripped apart buildings and wetlands, caused millions of dollars in damage, downed thousands of trees, and cut off electricity to half a million people for a week.
The CSSPAR scientists modeled the impact of a storm like Hurricane Isabel hitting the Chesapeake 70 years in the future, when the sea will be about 0.6 meters (two feet) higher than it is now. The Chesapeake Bay Observing System collected data from shore and marine-based weather stations, and the Virginia Institute of Marine Science used this data to simulate and predict future storm surges in the Chesapeake region.
The results of their modeling showed that flooding would be unprecedented. For instance, Isabel caused an eight-foot-high flood in Old Town Alexandria, Va. Add another 0.6 meters (two feet) to the bay, and the flood would be three meters (10 feet) high. In the nation’s capital, several national monuments, navy yards and crucial highways would be covered in deep, muddy water. The resort area of Virginia Beach, Va., would be economically damaged. Homes, hotels, roads, and islands would be flooded and muddy.
Though storms will become more powerful and violent, O’Connor hopes improved technology will reduce human deaths when future storms hit. Such technology can make real-time predictions about the impact of storm surges.
Satellite imagery and use of global positioning system (GPS) coordinates can help people understand the nature of a storm surge, how strong the surge will be, and how long it will last. Damage to homes, businesses, or transportation systems could be reduced.
“If we continue to improve these models, we won’t necessarily see the same impact on humans [as in past storms] because we would have a better system for educating people,” O’Connor said. In other words, this storm prediction technology could save lives.
The Chesapeake's Living Shorelines
To help protect the Chesapeake region, average citizens should first educate themselves about the ecology of the Chesapeake Bay as a system, said Sean OConnor, a National Geographic Society cartographer who has mapped sea level rise on the Chesapeake.
OConnor advocates cultivating natural environments along the coast called living shorelines. Erosion is controlled by placing rows of stone just off the shoreline, along which aquatic grasses are planted. Sand and mud are trapped naturally behind these "walls" of stone and grass. Shoreline is actually gained. Living shorelines have emerged as the preferred alternative to "hard" techniques such as retaining walls.
sharp or intense.
generally or near an exact figure.
having to do with water.
body of water partially surrounded by land, usually with a wide mouth to a larger body of water.
person who makes maps.
having to do with maps and mapmaking.
gradual changes in all the interconnected weather elements on our planet.
having to do with the buying and selling of goods and services.
American nonprofit organization with interests in environmental protection and economic development.
(Chesapeake Sea Level Rise and Storm Surge: Public Awareness and Response) organization that works to gather and distribute information about sea level rise and intensified storm surges on the Chesapeake Bay
type of evergreen tree.
(singular: datum) information collected during a scientific study.
fragile or easily damaged.
fallen or crashed.
branch of biology that studies the relationship between living organisms and their environment.
having to do with money.
community and interactions of living and nonliving things in an area.
large-scale undertaking or attempt.
act in which earth is worn away, often by water, wind, or ice.
to guess based on knowledge of the situation or object.
mouth of a river where the river's current meets the sea's tide.
a building or room that serves a specific function.
to catch or harvest fish.
to be or place at the side of something.
mass of ice that moves slowly over land.
Global Positioning System (GPS)
system of satellites and receiving devices used to determine the location of something on Earth.
to give beauty to something.
type of plant with narrow leaves.
environment where an organism lives throughout the year or for shorter periods of time.
tropical storm with wind speeds of at least 119 kilometers (74 miles) per hour. Hurricanes are the same thing as typhoons, but usually located in the Atlantic Ocean region.
long period of cold climate where glaciers cover large parts of the Earth. The last ice age peaked about 20,000 years ago. Also called glacial age.
structures and facilities necessary for the functioning of a society, such as roads.
area not near the ocean.
small indentation in a shoreline.
flooding or overwhelming.
body of land surrounded by water.
(1580-1631) English explorer and early resident of Virginia.
method of creating coastal land by using stones and marine grasses to trap soil, sand, and mud.
having to do with the ocean.
wetland area usually covered by a shallow layer of seawater or freshwater.
region surrounding a central city and has at least 15 percent of its residents working in the central city.
National Geographic Society
(1888) organization whose mission is "Inspiring people to care about the planet."
federal land set aside to protect objects of scientific and historical interest.
having to do with a government's navy, or military ships and crew.
place where government ships are built, repaired, and supplied.
to use more of a resource than can be replaced naturally.
having to do with the North and/or South Pole.
introduction of harmful materials into the environment.
to move a residence or business from one place to another.
having to do with people's homes.
facility or space people go to relax in a luxury setting.
structure built to hold back water (such as a river) or earth (such as a landslide).
to go back to a familiar or safe place.
photographs of a planet taken by or from a satellite.
base level for measuring elevations. Sea level is determined by measurements taken over a 19-year cycle.
increase in the average reach of the ocean. The current sea level rise is 1.8 millimeters (.07 inch) per year.
liquid and solid waste material from homes and businesses.
any aquatic organism that has a shell or exoskeleton.
to create an image, representation, or model of something.
abnormal rise in sea level accompanying a hurricane or other intense storm. Also called a storm tide.
body of flowing fluid.
sinking or lowering of the Earth's surface, either by natural or man-made processes.
sudden, strong movement forward.
the science of using tools and complex machines to make human life easier or more profitable.
wetland that is regularly flooded by ocean tides.
person who travels for pleasure.
movement of people or goods from one place to another.
weather pattern of swirling winds over a center of low pressure above warm ocean waters. Tropical storms are less powerful than cyclones and hurricanes.
never before known or experienced.
company or organization that distributes electricity, water, or gas to residents and businesses.
capable of being hurt.
entire river system or an area drained by a river and its tributaries.
area with tools and equipment for measuring changes in the atmosphere.
area of land covered by shallow water or saturated by water.