From his window in Broad Channel, Queens, Dan Mundy watches the tides of Jamaica Bay swing up and down, the pendulum of a celestial clock. “Right now, 10 a.m. past 1 p.m. is 25 minutes from low tide,” he said Tuesday. “It’s much lower now than it usually would be. The mudflats are larger.
When it comes to tides, what goes down will come up. By Thursday morning, Mr Mundy expects he will see tides two feet above the normal high – if strong winds don’t push them to greater heights.
A royal tide will unfold on Wednesday and Thursday as the gravitational forces of the sun, moon and earth are aligned in a landmark stroke of ephemeral geometry and rare power. It will raise the water level between one and two feet above normal high tides for many areas of the Atlantic coast. It is an entirely natural phenomenon. This year, a network of scientists is asking the public to photograph the tides at their peak, and then again in a week, at their usual heights.
Extreme tide can give a telescopic view of a future with rising seas, when tides could regularly reach levels they now only reach twice a year, said New York-New Jersey ecologist Kate Boicourt. Harbor Estuary Program.
“What we see on Wednesday and Thursday is probably what we will see normally by 2080,” Ms Boicourt said.
In Brooklyn, water from the East River will cover the steps at the base of the Manhattan Bridge. Across the river, the new pedestrian plaza along the Franklin D. Roosevelt Parkway is likely to get splashed.
Ms Boicourt said photographs could be emailed to her at [email protected] Other groups will collect images of king tides in Barnegat and Delaware bays, she said, and photographs are being sought by the Peconic Estuary Organization and the Long Island Sound Study.
Mr Mundy, a retired firefighter who lives on the only inhabited island in Jamaica Bay, said it would be easier for him to use the mudflats to see the difference between normal and royal tides, as a much of the bay is no more than a foot or two deep. An extreme low tide has an equal and opposite extreme high tide.
“The waves at the Battery Park docks would be a good reference point for extreme high tide,” Mr Mundy said. High tide at the Battery on Thursday will be at 8:51 a.m. and charts predict it will reach 6.3 feet, about 18 inches higher than last Thursday. If a weather front causes a storm, the winds could push it higher. High tide times for many areas are available at saltwatertides.com and other websites.
For the constellation of islands that make up New York City, sea level rise is no minor issue: Conservative projections predict a rise of 7 to 12 inches by 2050, and a panel convened by Mayor Michael R. Bloomberg said in 2009 that if rapid ice melting takes place, the increase could be 41 to 55 inches by 2080. (There is near unanimity among climatologists that global temperatures have risen and will rise for the rest of the century, but the rate at which glaciers are melting is unstable.)
“Five years ago, I was of the opinion that I hadn’t seen sea level rise,” said Mr. Mundy, president of Jamaica Bay Ecowatchers, a civic organization. “I’ve lived on the water all my life. I am 73 years old. My attitude is, show it to me.
“More recently, I’m starting to pull myself together. Either this island I’m on is sinking or the sea level is rising. Probably both.
In fact, sea levels in New York City have risen about an inch per decade for the past 100 years, due to natural geological processes, said Adam Freed, an official with the office of long-range planning and the sustainability of the mayor. Projected increases for the rest of the century take into account expected changes in climate.
“It’s not just two feet of water – it’s when you start to see the combined impacts of sea level rise with storms,” Mr Freed said: storm-induced flooding tropical like Irene, who interrupted subway service, would cover even more of the city.
Don Riepe, another Broad Channel resident, said he used to hoist furniture onto crates when the bad weather hit, but the storms seemed to intensify. Many global projections indicate bad storms will continue. “The Northeasts are the worst for us,” said Mr Riepe, who runs the Jamaica Bay Guardian programme. “I am concerned about the increasing intensity of the storms. It’s good to be careful now.