The Inevitable End

Early in Long Island’s 15,000-year history, sea level was more than 100 feet lower than it is now
Once the glacier stopped its advance and began to retreat to the north, its meltwaters ran easterly to the Peconics and south to the sea, carrying with them fine soil particles to form alluvial fans that ultimately became flattish productive farmland. Durell Godfrey

    There is an overriding theory in physics known as entropy: Energy is continually moving from a higher state of order to a lower one. Ski down a hill that starts out steep but ends in a long flattish plain and you’ll eventually come to a stop. You’ve reached an end entropic state. Having come to a standstill, should a cataclysm all of a sudden remove the ground from under the plain, you would freefall down until you hit solid rock. You will have reached a second end entropic state. The Energizer battery eventually runs out of juice, no matter how resolute the marching bunny. What the TV ad doesn’t tell us is that it took more than twice as much energy to create the Energizer battery than it yielded before it died. Given enough time, everything runs down!

    The oceans are a perfect example. They are fed by the runoff meltwater from retreating glaciers, which stand higher in altitude than sea level. Water runs downhill, a principle that was standardized by the Golden Greeks, as well as Aesop, but which has been known since before the evolution of modern man. Yes, when sea’s level rises it has more potential energy than before, but it took more energy to raise it than it would yield if let out.

    We get our energy mainly from the sun in the form of radiation, namely, visible light, which is converted to many different energy types — heat, electricity, carbohydrates, and the like. All of the energy stored in the coal, oil, and natural gas residing in the earth’s crust was derived from sunlight trapped by chlorophyll and other plant pigments that convert water and carbon dioxide into organic chemicals. As long as there is sunlight and plants and plant cells to capture it, radiant energy will be converted into other energy forms for use by humans.

    It is quite clear to almost everyone by this time that if all the ice in the form of glaciers, such as the massive ones in the Antarctic and on Greenland, melts, sea level would rise around the world by yards, not just by feet or inches. Early in Long Island’s 15,000-year history, sea level was more than 100 feet lower than it is now. That’s how long the world’s glaciers have been melting and giving up their water to the sea.

    At the end of the ice sheet’s last advance southward in the Northern Hemisphere from its northern base, Long Island’s south shore was on the order of two miles farther south than now. There was a tenuous land connection between the Jersey Shore, Staten Island, and Long Island, now widely separated by the Hudson and East Rivers. Early Long Island humans and wildlife could move along such a wide shore in either direction that it became a much-used migratory route. Since the construction of the Montauk Lighthouse in the first years of the 19th century, the ocean has cut into the land more than 200 feet, lately at a rate of two to five feet per year. Montauk and Block Island are the eastern remnants of the so-called terminal moraine, an assortment of rocks, sand, clay, silt, and organic materials called “till” that stretches all the way west to New York City’s bedrock. In central Long Island it is known as the Ronkonkoma moraine and is situated well north of the south shore.

    Once the glacier stopped its advance and began to retreat to the north, its meltwaters ran easterly to the Peconics and south to the sea, carrying with them fine soil particles to form alluvial fans that ultimately became flattish productive farmland. The sand particles didn’t travel as far south as the fine soil and were deposited in a belt south of the moraine that ultimately became populated with pitch pines and scrub oaks, know popularly as the Long Island Pine Barrens. Finer particles, or loess, blew in to make the soils behind the ocean loamier, more fertile, and more arable, such as the celebrated arable Bridgehampton soils covering much of the land behind the ocean between Shinnecock Bay on the east and Napeague on the west.

    After the retreat of the glaciers that dropped the terminal moraine, a second advance created the Harbor Hills moraine that runs along Long Island’s north shore from King’s Point on the west all the way to Orient on the east. When it retreated, it left behind the string of large boulders, or “glacial erratics,” that line the south shore of Long Island Sound. The glacier’s finer particles washed south, especially so on the North Fork, all the way to the Peconics, creating arable soils equal in agricultural value to the Bridgehampton ones.

    Not all of the meltwater from the two glacial advances ran to the seas. Much of it moved vertically downward through the sandier, more permeable soils, creating thick layers of subterranean freshwater, the groundwater that makes up Long Island’s three freshwater aquifers. When taken together the aquifers can be 1,000 feet thick in some central Long Island spots. If we could date the origin of much of that water, which is free of mineral and organic matter, we might find that some of it is thousands of years old. The layers are not static, they seep slowly toward the seas, the “sinks,” at rates rarely faster than a foot a day.

    Once pure, over the course of the last 200 years, large portions of the upper aquifer layers have become infiltrated with various pollutants — pesticides, petroleum residues, industrial chemicals, human metabolic wastes such as urine, medicines, and the like. Water from precipitation recharges the aquifers to the degree that during very wet periods the top of the upper glacial aquifer, the closest to the land surface of the three, will reach to approximately 70 feet above sea level. Lake Ronkonkoma, Long Island’s largest freshwater body, is a case in point. It is situated in the center of the Ronkonkoma moraine and its water level is nearly identical in elevation to the water table, i.e., the very top of the aquifer.

    There will be another ice age, but in the very distant future. Until then, we will have to abide by global warming and observe the changes in the flora and fauna as the temperate zone becomes more tropical and the tundra more forest-like. Just as a supertanker or aircraft carrier can’t stop on a dime, it is impossible to stop the rising of the seas; we can only adapt to the rise. Therein lies the question.

    What do we do? Retreat inland to higher ground? Raise the edge of the coast to keep up with sea level rise? If we could stop making war and killing each other, cut down on our carbon emissions, and plan for future millennia, we might be able to mitigate some of the most injurious impacts. Otherwise, we’ll have to start over, perhaps, on a habitable planet yet to be discovered.