Manhattan has been steadily sinking since the end of the last ice age. During the ice age, the weight of glaciers in Canada depressed the mantle, forcing the mantle to bulge around the edges of the ice sheet. (Think of poking your finger into the side of a water balloon.) When the glaciers melted, the mantle stress relaxed , and the northeastern US began to sink. (Think of removing your finger from the water balloon.) Tide gauges show a steady 4mm/year of sinking around Manhattan and New Jersey, over the last 150 years.
Central Park is 40 metres above sea level, and will be underwater in 10,000 years – unless we have another ice age, in which case it may be buried in ice. Whatever happens, it has nothing to do with CO2 or fossil fuel – and there is nothing we can do about it.
Q. What kind of morons would worry about things 10,000 years in the future? A. The New York Times