With the Republican Party securing control of the executive and legislative branches of government in the United States (with the judicial almost certain to follow), climate-change denialists will soon be in charge of environmental policy in the country. As a candidate, Donald Trump promised to withdraw the U.S. from December's Paris Agreement on climate change and dismantle Obama-era environmental regulations, including the administration's Clean Power Plan.

To get some perspective on what a President Trump will mean for efforts to combat climate change and the potential repercussions for New York City, Gothamist talked to professor Philip Orton, an oceanography researcher at the Stevens Institute of Technology and the author of a recent paper on the likelihood of New York being struck by another major hurricane like Superstorm Sandy. Like many people in the New York area, he was not pleased with Tuesday's results.

What was your reaction to Trump's victory? 

I was very alarmed and sad at the news. I have been really impressed with Obama's action and his successes and thought it was amazing for an American president to bring together hundreds of countries to sign a treaty of any sort. I thought he created amazing momentum. U.S. emissions had flattened off and now, I think with Myron Ebell as the person who's going to lead the EPA, and the things that Trump has said he's going to do, personally I'm just really sad, and really concerned that it might undo a lot of these things that were done. 

In terms of my field, anything with the word "climate" on it—we've already talked about changing the name of one of our projects because the federal funding for science is going to be severely threatened right now. I think that will include things such as flood forecasting, things that have to do with weather, and dangers from weather. It won't just have to do with what's going to happen in 50 or 100 years. It can also put people in danger in the near future too.

If the Paris Agreement unravels, what do you see as the long-term effects on New York City?

If we abandon those commitments and we don't do anything about climate change, then by 2100 we are going to have three to six feet of sea level rise and there will be doubts about the future viability for the city.

By 2100, the entire coastline of the United States will need funding every year. And there won't be funding to protect New York City anymore. There's not even funding today to build full protection against Hurricane Sandy-level floods. So when the whole country is looking for that protection, it's going to be a bad world that we live in. 

The more optimistic way of looking at it is a four-year presidency is just a moment in time relative to the scale of this problem that needs to be solved. We went through eight years of Bush and yet we were on track to actually do a lot with the changes Obama made. Emissions in the U.S. have actually come down. So a little more optimistically, a four-year presidency isn't going to be catastrophic.

But sea level rise is sort of a wicked problem, where there's a lot of inertia involved. Warming the planet occurs very slowly, and we've only had a degree Fahrenheit of warming so far since 1900—more if you look further back. There's a real delay in the warming. It takes a lot of time. There's a delay in that heat getting into the ocean, and then there's an even bigger delay, further down the line, in melting huge mountains of ice on Antarctica and Greenland. But once you start moving these things, they're impossible to stop.

I think a good analogy is that it's like pushing a disabled old car forward on a gentle downslope. It may be hard to actually start it moving, but once it's moving, actually getting in front of it and stopping it is going to be really, really hard. That's the inertia problem of sea-level rise with melting ice. 

Obviously, coastal resiliency efforts will require a lot of federal money—are there steps state and city government can take to mitigate the impact of climate change? 

For mitigating climate change, definitely the states can do things. If Trump gets his way, the states will be in charge. A lot of the states do have plans. You think of Michigan, it's less aggressive than what the Clean Power Plan would've called for, but they still have plans, actually. So that's a good thing. And regions often have plans, like the Northeast has a plan and the West Coast has its own plan, and they can create their own carbon market and things.

Sea-level rise scenarios for New York City.

In terms of resilience, there are some things that can be done, but in terms of sea level rise it's expensive. Retreat for a city is not very palatable. You don't want to retreat a city; it's already a densely populated area. It's not popular and maybe even a bad idea, at least in the short term. When it comes to sea level rise— that's a good question, what can states and cities do without federal funding? It definitely helps to have federal funding.

When you talk about three to six feet of sea level rise, what would that look like?

If we're talking about a 100-year flood, then we double the 100 year flood zone. That goes well beyond Sandy, so it's a lot more neighborhoods. At that point, a 100-year flood might cross lower Manhattan at Canal Street, for example.

If you want to talk about the tides every month, spring tide, full moon tide, every month, then neighborhoods that currently only flood during a bad storm once every five years or 10 years will flood every month. And that includes any place that's fairly low-lying, including a place like South Street Seaport. They would need levees.

Storms get more attention than they should in the climate change story. If a neighborhood starts getting flooded by nuisance flooding 10 times a year, just from the tides, that's the end of a neighborhood unless it has protection. When the streets are blocked every month and salt water is getting into the entire neighborhood, there's no way to live somewhere like that.

New York city does have a fair amount of elevation. Places like Miami, and Florida in general, are getting sunny day flooding. That's going to impact a lot of places more and more. We require some level of storm surge to get a flood, because we have a little bit of elevation. We build things up higher because we do get storms every winter.

Mostly, I'm talking about flooding, but there is also the heat-wave issue. Right now, we have about one 100-degree day every two years. If we look ahead to the latter part of the century, we are talking about—from the New York City Panel on Climate Change—about 14 to 20 100-degree days at high-end estimates.

The heat waves will get dramatically worse. And then if you do mitigate climate change aggressively, maybe we might say you'll get to the 25th percentile of the number of 100-degree days, which is only four. Four versus 14 to 20—it's still a heck of a lot more than one every two years. It's a very unpleasant world if you get 20 100 degree days per year. The whole summer would be one long heat wave.

Flooding near the Gowanus Canal during Superstorm Sandy in 2012 (Ed Kim/Flickr)

Where are the city's resiliency efforts right now?

A lot of things are being done. The 14th Street Con Edison facility and transformers that blew up during Sandy because they didn't have high enough protection, that's being protected. Sandy instigated a lot of movement. It's not all visible, a lot of it is infrastructure, protection of subway system, electrical infrastructure, a lot of those smaller things are being done. Which seem like they're more manageable.

But then if you want to ask, "Is every neighborhood being protected from another Sandy or sea-level rise, plus a winter storm, in 50 years?" Then I would say those things aren't being done, because that involves tens of billions of dollars more, which they don't have.

There are often headlines in the newspaper that say things like, "Global warming is happening faster than we thought." With extant climate-change models, how much is unknown? 

The science is very strong. But there's big uncertainty still—for example, with sea level rise. By the end of the century, New York City is looking at roughly two to six-and-a-half feet of sea level rise. That's the uncertainty range. That includes the uncertainty about how humans are going to behave. Are we're going to elect a bunch more Trumps or elect a bunch more Obamas?

It also includes the uncertainty about how the system behaves. It's hard to see how mountains of ice are going to melt and accelerate, and that's the big uncertainty.

This interview has been edited for length and clarity.