The sea level is rising and the land in Virginia is sinking

 NORFOLK, Va. -- Sea-level rise is mentioned in the media nearly every day. But what is really happening and what should we do?
With a simple yardstick stuck into the ground you can measure sea-level rise. Well, it's not quite that simple, but that is essentially what the National Oceanic and Atmospheric Administration and its forerunners have been doing since the mid-1800s in the Chesapeake Bay. At its water level stations, NOAA has measured a slow but steady rise of sea level relative to the land. Yes, the tide goes up and down and the wind blows water into and out of the bay. But the ocean has been steadily rising almost 2 inches every 10 years relative to the land surrounding the lower bay.

The main reason for this rise can be traced to the Earth's glaciation period, around 20,000 years ago, and to the warming that has happened since. At the height of the glaciation period, northern New York and eastern Canada were covered by large ice sheets. At the same time, there were glaciers in northern Europe and in the valleys of the Alps and Andes, and ice caps in Greenland and Antarctica were extensive. Since then all of those ice masses have been melting. The melt water has run into the ocean, and the ocean has risen. The bathtub is filling.
A logical question: Is the rate of melting of the huge Greenland and Antarctic ice caps changing? That question is behind much of today's commentary about sea-level rise and climate change. If the melting rate is increasing (every year more water goes in the ocean than went in the year before), planners and engineers need to know.
Besides the added water from melting glaciers and ice caps, the ocean is warming a bit, and as the water warms it expands, creating more sea-level rise. The warming of the ocean has been well-documented by oceanographers using ships, autonomous drifters and satellites.
Another reason the water level in the Chesapeake Bay is slowly rising is because the land is sinking. Those 1-mile-thick glaciers that covered New York and Canada thousands of years ago pushed the land down, and the Chesapeake Bay went up - like a teeter-totter. Now the glaciers are gone; New York and Canada are going up and we are going down.
So you add it all up and the ocean is rising relative to the land in Virginia. The rate is around 4 to 5 millimeters per year. (Geological processes, mentioned above, are causing land to rise in various northern regions, including Alaska, where relative sea level is dropping.)
Four centuries ago when our ancestors settled the Chesapeake Bay, they built their homes on tidal creeks and low-lying islands. They built hunting lodges. Everyone, it seems, wants to live near the water. But since that time, the sea level has been slowly rising.
The rising water has direct impact on all that we have built: tunnels, low-level infrastructures, bridge supports, harbors, ports, airports and so on. It also affects parts of the natural environment such as wetlands in the Blackwater Wildlife Refuge.
What should we do?
Perhaps the question should be: What can't we do? And the answer to that is: We cannot stop it. Earth's processes causing sea-level rise are way beyond our control.
So, like the Dutch with their Delta Works and the English with their Thames Barrier, we must devise means to deal with sea-level rise.
That, essentially, is already the response of the U.S. Army Corps of Engineers, which is responsible for building nearly every federally owned structure on our coasts, including breakwaters, levees, channels and docks. The corps has the following directive: "The planning and design of USACE water resource projects in and adjacent to the coastal zone must consider the potential for future accelerated rise in 'global mean sea level' to affect the local (mean) sea level trend." Many other governmental agencies endorse a similar policy statement.

Sea-level rise isn't going to happen overnight. It will slowly creep up on us. Even the Dutch, to a large extent, ignored their problem until the great North Sea floods of 1953. As with the Dutch, it will probably take a large flooding event - one exacerbated by the general rise in sea level - to really get our attention.

Understand that sea-level rise is not a subject for political debate. Sea-level rise is happening and has been for thousands of years. Actions of the Army Corps of Engineers, the Navy, and the planning districts of Virginia show that experts are very much focused on this threat.
Climate change over the coming years will affect the rate of sea-level rise, and indications are that the rate of the rise is increasing.