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Education: Baruch director’s work on climate change wins award

By Jackie R. Broach
Coastal Observer

When James Morris started measuring the growth rates of marsh grasses at North Inlet in 1984, it didn’t have anything to do with climate change.

Yet within a few years, he was finding a lot of variation from year to year in the growth rates of those grasses, which he eventually linked to sea level rise.

“It’s a case of serendipity, I guess,” said Morris, director of the University of South Carolina’s Belle W. Baruch Institute for Marine and Coastal Sciences. “Science, I think, often advances because of fortuitous accidents.”

This particular accident led Morris to receive the Society of Wetland Scientists’ 2012 Merit Award last month for a paper he wrote that demonstrated for the first time a positive feedback between sea level rise, plant growth in salt marshes and sedimentation rate that explains how marshes respond to sea level rise.

The award is presented in recognition of an outstanding piece of original research, achievement or contribution to wetland science.

Morris is a Columbia resident and Yale alum with a Ph.D in forestry and environmental studies. He is also a professor of biological sciences and distinguished professor of marine studies at USC.

Thinking back to that early work, Morris said it took him a while to explain what he saw taking place at North Inlet.

“The results were surprising to me, because at the time we all thought of salt marshes as being pretty predictable environments,” he said. But the rate of growth for the marsh grasses bounced around from year to year because that’s what sea level was doing.

“It doesn’t just rise slowly and gradually and nicely from year to year in a linear pattern,” he explained. “It can be higher or lower from year to year by quite a bit and the grasses were responding to those changes. When sea level was high, grasses were growing better.”

When he put his theory to the test, he found marsh grass growth wasn’t necessarily keeping up with sea level rise, and the role of sedimentation in marshes also came into play.

It gets complicated, but the gist of it is more plant growth means more sediment is trapped and the elevation of the marsh builds up gradually to compensate for the increase in sea level.

All this work led to a model able to forecast how marshes will change with rising sea levels.

“If you use that and project how marshes will respond, it seems fairly clear marshes will begin to disappear and North Inlet will become an open water lagoon,” Morris said. He compares the effect to North Carolina’s Pamlico Sound, which used to be marshland, but it doesn’t accumulate a lot of sediment and has not kept up with sea level rise.

“We’ll always have marshes, provided we allow room for them to migrate, but there won’t be these vast expanses of marshland areas like today,” Morris said. “A fringe of marsh will always be there and migrate inland as sea level rises until it reaches some sort of barrier.”

Sea level is predicted to rise three feet over the next 100 years, ramping up slowly, then rising much faster in the second half of that period. Morris said he believes it’s time for coastal residents to start planning for that eventuality.

Planning should start with using topography to project where the coastline will be under various scenarios. Once it’s determined which places are likely to be under water in 50 or 100 years, “those are the places we ought to start looking to encourage people to start moving back from the coast,” he said. “The planning people have a phrase I really like. It’s called ‘organized retreat,’ done through a system of zoning, taxation and insurance, and all the regulatory tools we have.”

That would focus on less populated areas.

“We’re certainly not going to abandon cities like Charleston, for example,” he said.

“That’s just out of the question. Those cities will probably have sea walls built around them, like New Orleans today. They’re important cultural resources that have to be protected.

“The kind of retreat I’m talking about is more appropriate in rural areas on the coastline. Though today there’s not much rural area left on the coast. In South Carolina we have a big advantage in that between Georgetown and Charleston there’s not much population. We’ve got these huge national forests and large tracts of land protected from development. For us, that’s a big insurance card.”

It might all sound a little frightening to layman.

But “from a scientific point of view, it’s pretty exciting stuff,” Morris said.

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