Saying we “must prepare for the growing exposure of our military bases to sea-level rise,” a new study by the Cambridge, Mass.-based Union of Concerned Scientists (UCS) calls on the Pentagon and Congress to devote substantial resources to protecting national security from the threat of climate change.
The study, “The U.S. Military on the Front Lines of Rising Seas,” examines 18 coastal installations stretching from the Portsmouth Naval Shipyard in Maine down to the Naval Air Station in Key West and on to Elgin Air Force Base in the Florida Panhandle. UCS’s list of endangered bases also includes such iconic names as the U.S. Naval Academy in Annapolis, Md., the Marine Corps Recruit Depot on Parris Island, S.C., and the Washington Navy Yard.
What all these places have in common, according to UCS, is that they “are at risk of permanently losing land to the ocean in the decades to come.” “As sea levels rise,” the group explains, “high tides will reach farther inland. Tidal flooding will become more frequent and extensive. When hurricanes strike, deeper and more extensive storm surge flooding will occur.”
Reliance on a Computer Model
This vision is indeed frightening, but, like much of what passes for climate science, it is not based on actual observations but on assumptions that are fed into a computer model, which projects a range of possible outcomes many decades into the future. In this case, each base’s exposure is calculated on the 2014 National Climate Assessment’s midrange or “intermediate-high” sea-level rise scenario. Using a National Oceanic and Atmospheric Administration (NOAA) computer model, UCS projects a global average increase of 3.7 feet above 2012 levels by 2100. It also uses a “highest” scenario based on a more rapid rate of increase, which projects a global average sea-level rise of 6.3 feet by the end of the century.
With the latitude afforded it by its embrace of the National Climate Assessment’s assumptions and NOAA’s computer model, UCS had little trouble showing how coastal flooding will imperil vital military installations. Among its findings:
- By 2050, most of the bases it examined will see more than 10 times the number of floods they experience today.
- By 2070, half the installations could experience 520 or more flood events annually – the equivalent of more than one flood daily.
- By 2100, eight of the bases will be at risk of losing 25 percent to 50 percent or more of their land to rising seas.
The U.S. Navy’s giant base in Norfolk, Va. is one of the installations evaluated in the UCS study. Located near the mouth of the Chesapeake Bay, the base, according to UCS, is in for trouble. The study says waters at the base could rise as much as two feet by 2050 and 6.9 feet by 2100.
The Role of Geological Instability
But at Norfolk and other coastal bases, there is something else going on. These areas are subject to what geologists call “land subsidence,” the gradual sinking of land either under its own weight or under the weight of manmade structures on top of it or both. Geologists differentiate between absolute sea level, a measure of the volume and mass of ocean water, and relative sea level, the level of ocean surface measured relative to land or a tidal gauge. In a 2010 report submitted to the U.S. Army Corps of Engineers, the Virginia Institute of Marine Science found that 50 percent of the relative sea-level rise at Chesapeake Bay water-level stations between 1976 and 2007 was due to subsidence. At Norfolk and other bases subject to subsidence, it’s not just the seas that are rising, but the land that’s sinking.
What’s more, the Pentagon’s own estimates of sea-level rise at the Naval Station Norfolk are far below the figures produced in the UCS study. The Defense Department expects the seas will rise at the Norfolk facility between one-quarter of an inch and one inch by 2050.
Preparing for “Heavy Weather”
Accustomed to dealing with the whims of nature, the Navy, as a precaution, is raising piers at the Norfolk facility and retrofitting them with double decks. This, a Navy official told bayjournal.com (July 27), will make it easier to access utilities and reduce damage during “heavy weather.”
Manmade structures – commercial, residential, and military – along the U.S. Eastern Seaboard and Gulf Coast were subject to storms, floods, and erosion long before “climate change” (formerly known as global warming) became politically fashionable. In the Mid-Atlantic and Northeast, for example, sea levels are affected by, among other things, the North Atlantic Oscillation, a see-saw in atmospheric pressure and wind fields between Iceland and the Azores.
Globally, sea levels have been rising at a rate of around three feet per century for the past 19,000 years, a process that began when the melting of giant ice sheets signaled the end of the last Ice Age (Pleistocene Epoch). Thus, there is a connection between “climate change” and sea-level rise, but the change in question took place thousands of years ago and is unrelated to the trendy notion of human-induced global warming.
Before the Pentagon redirects funds from troop readiness, equipment maintenance, and other priorities to confront the scary scenarios UCS has laid out, it should bear in mind that climate and weather are fickle and that judicious adaptation to whatever Mother Nature serves up is the most prudent course to follow.
Bonner R. Cohen, Ph. D., is a senior fellow at the National Center for Public Policy Research.