What Do Climate Change & Rising Seas Hold In Store For New York City?

Even if greenhouse gas emissions were to completely cease all around the world this very instant, many of the “worst” effects (to humans) of anthropogenic climate change would still be unavoidable. This would be owing to the emissions we’ve put out there to date (and the lag on their effect on the environment) as well as the positive feedback loops that have already kicked in.

One of these effects is significant sea level rise. At this point, there is essentially nothing that can be done to stop sea level rise significant enough to make many of the largest coastal cities and seaports of the world non-livable.

Miami and New York City are two of the most obvious cities, and are symbolically important. But, if you were to ask the average person on the street in one of these cities if the issue concerned them, they would be likely to shrug. Perhaps they’d say something about some technology or other saving these cities, human ingenuity, blah blah blah.

The thought that cities like Miami and New York City (and New Orleans, for that matter) may have to be abandoned at some point, owing to the fact that it will become uneconomical to continue putting expensive stopgaps in place, seems to unthinkable to some people — or, at least, unspeakable. But this is one of the effects of global warming and climate change that we have to come to grips with.

When you look at the sort of sea level rise that’s now in store, even using very conservative projections, it’s clear that this is an inevitability. New York magazine recently published an interesting article on the matter written by contributing editor Andrew Rice. There are several bits here that I wanted to highlight:

Klaus Jacob, a German professor affiliated with Columbia’s University’s Lamont-Doherty Earth Observatory, is a geophysicist by profession and a doomsayer by disposition. … Jacob believes most people live in an irrational state of “risk denial,” and he takes delight in dispelling their blissful ignorance. … “I have made it my mission,” Jacob says, “to think long term.” The life span of a city is measured in centuries, and New York, which is approaching its fifth, probably doesn’t have another five to go, at least in any presently recognizable form. Instead, Jacob has said, the city will become a “gradual Atlantis.”

The deluge will begin slowly, and irregularly, and so it will confound human perceptions of change. Areas that never had flash floods will start to experience them, in part because global warming will also increase precipitation. High tides will spill over old bulkheads when there is a full moon. People will start carrying galoshes to work. All the commercial skyscrapers, housing, cultural institutions that currently sit near the waterline will be forced to contend with routine inundation. And cataclysmic floods will become more common, because, to put it simply, if the baseline water level is higher, every storm surge will be that much stronger. Now, a surge of six feet has a one percent chance of happening each year — it’s what climatologists call a ‘100 year’ storm. By 2050, if sea-level rise happens as rapidly as many scientists think it will, today’s hundred-year floods will become five times more likely, making mass destruction a once-a-generation occurrence. Like a stumbling boxer, the city will try to keep its guard up, but the sea will only gain strength.

… In his public talks, Klaus Jacob likes to show a similar map, depicting what New York’s coastline might have looked like in the mid-Pliocene epoch, 3 million years ago, the last time the amount of carbon in the atmosphere was around today’s level of 400 parts per million. Sea levels were some 30 meters — or nearly 100 feet — higher.

… To behave as if the New York coastline is an immutable fact is to disregard not just science but history. Over a few centuries, humans have thoroughly remade the city’s topography, leveling hills, channeling streams, draining ponds, creating new landfill out of construction debris. When workers were excavating the foundation of the redeveloped World Trade Center, they discovered, buried deep beneath the ruins, the hull of an 18th-century shipwreck — an eerie reminder that even our tallest towers sit on land claimed from the water. Our ingenuity, and our real-estate speculation, have made the city a continually expanding entity. We are not used to contemplating contraction.

After Sandy, Mayor Bloomberg pledged to direct some $20 billion in disaster aid into “climate resiliency” measures, such as floodproofing buildings by moving mechanical equipment to upper floors. In areas that were hit hard by the storm, many homeowners have taken advantage of a city program called “Build It Back,” reconstructing their houses high up on stilts. Beneath this defiant civic agenda is an old, blithe assumption that New York is too rich, too important, too tough, to ever give up an inch of real estate. “We still have essentially the gung ho, Wild West way of doing business in this country, where we think we are the master of nature,” Jacob said. “Fighting, building barriers, instead of accommodating the ocean.”

If sea-level rise reaches 2.5 feet, the floodplain for a hundred-year storm will expand to nearly a quarter of the city. The climate-change panel predicts that could happen by 2050, which still leaves some time for long-range planning. That is the kind of foresight that used to be New York’s specialty: The Commissioners’ Plan of 1811, for instance, established the street grid that defines Manhattan above Houston to this day. At present, however, the city appears to be unable to accept the fact that it faces an inevitable reckoning. The human tide is moving in the wrong direction, still marching toward the waterline.

… The answer is buried in the Earth’s glaciers, which warehouse enough water to increase sea levels by some 230 feet. In her 2013 book Rising Seas, Gornitz writes that although the glaciers have been stable for the last 6,000 or so years, they have fluctuated in the geologic past, freezing and then thawing in “pulses.” The last time the climate was this hot, around 100,000 years ago, the oceans were between 13 and 30 feet higher than they are today. It’s reasonable to assume, therefore, that we’ve already locked in that amount of sea-level rise; with a few more degrees of warming, we could be looking at truly biblical scenarios.

A “few more degrees” of warming is seemingly inevitable at this point, it should be remembered, considering that even in best-case scenarios, the transition away from fossil fuels, industrial agriculture, sprawling cities and suburbs, consumer culture, and associated emissions would take a fair amount of time.

While renewables, energy storage technologies, electric vehicles, etc., certainly are becoming more economically attractive, they won’t save cities like New York, Miami, and London.