In Observations

Sea level is not as level as you might imagine.

The ocean at Bermuda is about three feet higher than the ocean at the mouth of Chesapeake Bay—an ocean that would seem poised to gush downhill and drown Tidewater Virginia.

It doesn’t, because the earth, whose rotation is what causes the ocean’s Bermuda-to-Bay slope, keeps on spinning.

It’s actually more complicated than that, explains oceanographer Bill Boicourt, emeritus at the University of Maryland’s Horn Point laboratory, on the front lines of researching climate change and sea level rise as it affects the Chesapeake.

There’s the Gulf Stream, that great river of ocean current flowing off the East Coast. It acts as a sort of ‘speedbump’ that impedes the flow of ocean water into the Chesapeake. Shifts in its strength and its location, also changes in prevailing wind directions offshore, can cause tides in the Chesapeake to be higher—or lower—than average for periods of a couple years or more.

Boicourt pauses…”Actually it’s more complicated than that…”.

I’ve known “Dr. Tide”, as his kayaking buddies have come to call Boicourt, since we were students at Johns Hopkins more than fifty years ago. I can always depend on him to complicate my life as an environmental writer, to dissuade me from the compelling, but simplistic story I was planning to write.

It’s exactly what good scientists do. “Our worst critics. . . people challenging our views on climate change come from friends who are scientists,” he tells me, Dave Harp and Sandy Cannon-Brown on camera during filming of High Tide in Dorchester.

We’re trained as scientists to be skeptics. . . is that really true? is the first question we ask. “It does not lead to happy marriages,” Boicourt responds. “You come home and a statement’s made and the first reaction is ‘you can’t really say that’, but that’s the way we’re trained.”

We made this film to educate the public on the very real prospect of rapidly rising sea levels in the Chesapeake. It also became an education for us on communicating complex science to a citizenry who mainly wants to know, ‘how’s it going to matter to me?’

Talking to ‘Dr. Tide’ reminds me how easy excellent climate science—always complicating, always arguing—lends itself to unscrupulous cherry-picking of data by forces who have sought only to discredit and sow disinformation about what human fossil fuel burning is doing to the planet.

If that’s your game, and it has been the game played by too many energy lobbyists and their political pawns, then it’s simple to ‘prove’ that sea level’s falling, or that scientists don’t even believe one another.

It’s really only in the last five years or so that he’s satisfied himself, Boicourt says, that a serious acceleration is underway that will raise sea level around the Chesapeake about two and a half feet by around 2050, and 5-6 feet by century’s end.

“There are so many factors that influence the sea level. . . over the last century of water level in Chesapeake Bay, the water has gone up. . . very clearly one foot per century.

“And some of my friends say, ‘how can you claim that we are really getting an acceleration of that to two and a half feet. . . and you get years when the water level’s going down? What’s going on here?’.”

How do we get from one feet a century to two and a half feet? Because of this short-term noise, we call it, the variability year to year, it’s hard to prove that acceleration—until recently.

“Now, there are on the order five papers who have unambiguously shown that (it is happening),” Boicourt says.

A couple feet of rise in average sea level, which is to say high tide will be a couple feet higher everyday, as will storm surges, he explains, “does not seem like a lot to people, but in Dorchester county it means quite a bit.

“In south Dorchester the slopes of the ground are such that for every foot (of sea level rise) you can go a mile inland further in flooding. . . you’re essentially covering a great part of south Dorchester. . . “.

It’s not just Dorchester, says Boicourt. “If you look around the Bay, every county that I’m familiar with has low lying areas with people living it. . . People are going to have to move in the next 20 years, or to large mitigation, dikes, walls. . . huge expenses.”

“Communicating climate change has proven to be very difficult, especially for scientists who don’t speak in language that conveys simple concepts very well. When people do not want to really embrace the possibility that climate change is happening it’s more difficult.”

When he talks to locals, Boicourt says, “I refer them to people (like) Lee Bailey, who in Talbot county has made most of the docks there. . . That company is now building their docs higher and higher over the years, just of the history of that company which is not that old.”

Scientists, he says, aren’t only in it for research. “. . . they care about it. They worry about it for their future and their children. At Horn Point here (on the Choptank River) we can look out the window and see sea-level rise. We can go down to Blackwater, which is hauntingly beautiful. . . one of the most beautiful landscapes in the Bay, and see dying trees and marsh loss.”

Adapting to higher water and the increased erosion it will bring depends on where one lives, Boicourt says. Larger cities and higher ground may have the time and resources for engineering solutions like dikes and seawalls.

For places like lower Dorchester, adaptation may involve “retreat. . . that sounds awfully severe. Part of the adaptation is recognizing what’s going to happen in as accurate a projection as possible, and then planning for that. . . an orderly retreat is a possibility, where you use the land for the maximum public good during that time.”

 

 

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