Coastlines plumbed for ancient data in Pentagon climate study

 (10/06/2009)

Evan Lehmann, E&E reporter

The Pentagon is studying how rising seas and strengthening storms could affect coastal bases, perhaps causing facilities to be abandoned or moved over the next century.

About $5.5 million is being spent on studies in four areas -- Florida, Southern California, North Carolina and Virginia -- that are susceptible to climate change. Some of the projects are designed to look back thousands of years in the natural historical record to get a firmer grasp on the future effects of things like hurricanes, saltwater intrusion, shifting coastlines and expanding oceans.

The results could be used to develop adaptation strategies within the Defense Department, which has bases that occupy some 30 million acres in the United States, much of it on vulnerable coastline.

"It'll be used to assess risk, [and] it'll hopefully be used for planning purposes, and down the road we'll look at research opportunities for [climate] adaptation," said Jeffrey Marqusee, executive director of the Strategic Environmental Research and Development Program (SERDP), an environmental science initiative for the military. It was created by Congress in 1991 and is the brainchild of then-Sen. Albert Gore (D-Tenn.).

Would the Pentagon retreat from the sea?

The Pentagon is concerned about its sprawling coastal infrastructure, such as bases for the Navy and Air Force, and also natural areas like beaches used for training exercises that might be lost to sea level rise.

Elgin Air Force Base, for example, is a huge complex on the Florida Panhandle with facilities on low-lying barrier islands. The base is a training ground for special forces units, and is home to various fighter jet wings and an air munitions test unit. Norfolk, Va., is home to much of the Atlantic fleet.

The Pentagon recently contracted with Florida State University for $1 million to provide better data about the frequency of hurricanes and probability of sea level rise. The data will be used in computer models to assess the risk to the base.

"They have some major facilities out there on a strip of land only a couple meters above sea level," said Joseph Donoghue, an associate professor of geology at FSU and the study's lead investigator. "It's a fact that sea level is rising; it's only a matter of how much."

"They might have to build higher sea walls," he added of the military's adaptation options. "They might have to abandon buildings, move buildings, move roads, that kind of thing."

Marqusee, who said all four area studies would be complete by 2011, described the potential adaptation measures as "pretty broad."

"I don't think we have our hands around what the options are right now," he added.

Mining ancient lakes for a better grasp on the future

Seven researchers are working on the Florida studies. Donoghue is heading the "paleo-storm" research by collecting geochemical samples from the bottom of rare inland lakes that are infiltrated by saltwater surges during only the strongest hurricanes.

He hopes to develop a storm record going back thousands of years to get a better grasp on what could happen in the future. Many current computer models use a relatively short historical record -- going back about 150 years -- to determine the probability of tomorrow's storm frequency.

"It might not be representative of the true geologic story going back about 6,000 years, which is the period shown in these lakes," Donoghue said of current models. "You can smooth out some of the bumps."

FSU is also looking at coastal deposits to glean an older record of sea level rise, perhaps going back to the last "glacial maximum" about 20,000 years ago. Current data come from tide gauges dating back 100 years and from satellite imagery used for the past 15 years.

"We're using all those things and trying to create a model to see what sea level will do over the next 100 years or so," Donoghue said.