by James A. Bacon
Scientists Scott Hardaway and Bryan Watts, both affiliated with the College of William and Mary, have made a specialty of studying hummocks along the Chesapeake Bay coastline. Hummocks, which are stands of trees growing in patches of dry land surrounded by marsh, are a visible gauge of rising sea levels. As the water level creeps higher every year, the hummocks get more water-logged and the trees die, leaving stands of ghostly white spires. “We can show tide-gauge data until we’re blue in the face, and sometimes that doesn’t work” to convince the skeptics, Hardaway told Rex Springston in the Times-Dispatch.
Rising sea levels — or sinking land, take your pick — is a reality along Virginia’s Atlantic Coast. The sea level in the Chesapeake Bay rose about 1 1/2 feet over the past century. About half of that came from a natural subsidence of the land in southeastern Virginia. The other half came from rising sea levels globally. Larry P. Atkinson, an Old Dominion University oceanographer, suggests that half of the sea level rise can be attributed to natural warming underway for thousands of years and the other half from human causes.
You can dispute Atkinson’s estimate for the extent to which human activity is to blame, along with even more dire prognostications that human-caused global warming will accelerate, triggering a massive melt-off of glaciers and icecaps and pushing sea levels two to seven feet higher by 2010. What you can’t dispute is that sea levels along Virginia’s coastline have risen at a rate averaging one tenth of an inch per year over the past century and that there is considerable evidence that they continue to rise.
According to Springston, a sea-level increase of only one foot could damage or destroy $187 million to $249 million in houses, roads and wetlands in the Middle Peninsula alone. Local government officials in flood-prone areas are giving more thought to how to cope with the rising tide, whether by dikes and levees, flood-proofing houses or restricting development in low-lying areas.
As I have made abundantly clear in previous posts, I am skeptical of many of the claims made about Global Warming. I am open to propositions that are based on science (of which I am respectful) and contemptuous of assertions based on economics and public policy (much of which I regard as social engineering run amuck). While I acknowledge that scientists are as vulnerable to group think as anyone else and might be wrong about accelerating rates of sea level rise, I would suggest that anyone who dismisses their fears out of hand is just as guilty of pre-judging the science as those they criticize. Prudent people will keep an open mind and endeavor to gather the facts…. if only we could determine them with a high degree of assurance.
Which brings me to the North Carolina Sea-Level Rise Assessment Report, which aimed to measure sea-level rise in the Tarheel state, Virginia’s next-door-neighbor. The 2010 report forecast that sea levels could rise between 15 and 55 inches by 2100. One can characterize those projections as exaggerrated, as the American Tradition Institute has done, on the grounds that local tide-gauge measures are too crude to be reliable, satellite measurements have been available for only 10 years, and so on. But even skeptics like ATI concede that sea levels may be rising in the long run.
Lawmakers, very few of whom are climate scientists, have no way to authoritatively judge which side is right. In our ideologically polarized society, Democratic politicians will likely side with the Warmists no matter what, and Republicans will side with the skeptics. As an empiricist, I personally prefer to side with the evidence. It would take a modest investment to design and maintain a system of tide-measuring stations on the Atlantic and Chesapeake Bay that can measure the rate at which Virginia’s coastline is disappearing under the waves. My friend Steve Nash, who is researching a book about Global Warming and sea-level rise in Virginia, suggests that air-borne laser-based LiDAR (Light Detection and Ranging) technology can map the entire coastline for several million dollars. That sounds like cheap insurance. For a small investment we can ascertain definitively what is happening and provide our coastal communities solid data upon which to inform their actions.