Environment
12:59 pm
Wed October 31, 2012

Sandy Raises Questions About Climate And The Future

Originally published on Wed October 31, 2012 2:12 pm

If you ask climate scientist Radley Horton, it's difficult to say that Hurricane Sandy was directly caused by climate change, but he sees strong connections between the two. Horton is a research scientist at The Earth Institute at Columbia University. He says that in New York City, the sea level has gone up about a foot over the past century and that researchers expect that rise to continue and even accelerate.

"Given the higher sea levels in the future, even if storms remain exactly the same, we're going to get more frequent flooding events, maybe three times as many coastal flood events by the end of the century, just by virtue of having average sea levels be higher," he tells Fresh Air's Terry Gross.

It's difficult to know whether this year's rise in ocean temperatures was associated with climate change, but Horton says that Hurricane Sandy moved over unusually warm waters in the North Atlantic. "As the planet continues to warm, we expect ocean temperatures to go up," says Horton. "All things being equal, that does give a storm like Sandy more energy."

Horton is also the climate science lead for the science policy team of the New York City Panel on Climate Change, which has worked to prepare the city for climate hazards. He says that because Hurricane Sandy was unprecedented, it's a moment to learn about the many different types of impact a storm can have — for example, flooded subways. "We have several major tunnels with a huge amount of water in them," says Horton. "And even once that water is gone, it's salt water — salt water and electricity do not mix — so it's going to take a lot of time to test some of the electrical signal equipment."

In addition to the damage to cellphones, Internet and electrical equipment in building basements, Horton says the storm also revealed a vulnerability to fires in some of the coastal areas. He asks: "Is that something we fully understood and are there steps that can be taken to augment these heroic efforts that we saw from the firefighting community?"

Horton says another area of future research is the Northeast's long history of industry — much of which reaches back before times of regulation, when hazardous materials polluted the soil. "I think moving forward we just need to research and see if some of those hazardous materials got into floodwater and if it did, are there steps we can take in advance of the next storm to try to prevent that from happening again."


Interview Highlights

On melting sea ice, and how it can steer hurricanes like Sandy in unusual directions

"We've got approximately half as much sea ice in the Arctic in the fall now as we did say, 30 years or so ago — there's been this dramatic decrease. There is emerging research — my colleagues and I published a paper last February on this — suggesting that as that sea ice melts it's changing the jet stream, a current that steers weather in the mid-latitudes, places like New York. As sea ice melts, our research suggests that the jet stream is going to tend to get weaker. As the jet stream gets weaker, it's easier for storms to stagnate or in some cases, maybe even move to the west, which is what this storm did.

"Most hurricanes, as they get as far north as a place like New York, especially late in the season — September, October — [the] standard pattern is for that strong jet stream to push those storms to the east. What we saw with this storm was that it moved to the west. It's a very unusual track and I would say it's a big research question whether we might see in general more stormy weather and storms taking a track like that as sea ice melts."

On melting sea ice and rising ocean levels

"The melting of sea ice in the Arctic has very little effect directly on ocean levels — because you can think of it really as, ice that's sort of already floating on water. As it melts, it doesn't directly affect sea levels. But there's emerging research suggesting that as the Arctic Sea ice melts, it warms the atmosphere around it. So we need to look at these major ice sheets nearby, especially the Greenland ice sheet, and ask the question of whether the Greenland ice sheet is experiencing warmer air — changes to maybe more rainfall events instead of snow in some parts, and also warmer waters as that Arctic ice melts, as that eroding [of] some of the bases of these ice sheets on Greenland, in ways that make it easier for the land-based ice on Greenland to move to the water. Because if your ice that's on land moves to the water, then you do see an impact in sea level rise. That's emerging research, but I think it's potentially a hazard that could contribute to sea level rise in the future."

On how the New York City Panel on Climate Change helped prepare the city for Hurricane Sandy

"There was a major effort led by Bloomberg to really get a whole group of agencies, private sector companies to the table. And there was a role for experts — everything from climate scientists to risk management experts, members of the insurance community for example. And I think as a result of that process, New York City did document some of the key vulnerabilities and took some specific adaptation steps as well. Adaptation's a process, but some of the key steps that were initiated included beginning the process of elevating some of the key infrastructure, including a wastewater treatment plant in the Rockaways. Steps are being taken to elevate some of those pumps. But you're also seeing a push in the last few years towards these sort of green infrastructure solutions to try to capture rainfall, floodwaters, and also along the coast to sort of buffer the coast through building up of marshes and such to limit the effects of storm surges."

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Transcript

TERRY GROSS, HOST:

This is FRESH AIR. As a native Brooklyn girl and current Philadelphian, my thoughts have been with everyone whose lives have been turned upside down by Hurricane Sandy. I think most of us are wondering, was Sandy an outlier? Or is it an example of the kind of intensified storm we should brace ourselves for in the future? We called Dr. Radley Horton of the Center for Climate Systems Research, which is part of the Earth Institute at Columbia University.

He also serves on the New York City Panel on Climate Change as the climate science lead for the science policy team. We reached him at his home in Garrison, New York, about 50 miles north of New York City. He lost electricity but he has a generator and his landline phone is working.

Dr. Radley Horton, thank you for your time and welcome to FRESH AIR. So let's start with the question of climate change. How much, if at all, do you think climate change contributed to Sandy being as massive and powerful as it was? Or is that an impossible question to answer?

DR. RADLEY HORTON: I think it's a difficult question but I think there are some important aspects to it that we should address. I think there are really sort of three parts to the answer. The first thing to emphasize is that sea level rise has gone up about a foot in New York City over the last century. What we know with certainty is that sea levels are going to continue to rise.

They're going to accelerate beyond those rates we saw in the past and given that, given the higher sea levels in the future, even if storms remain exactly the same we're going to get more frequent flooding events - maybe three times as many coastal flood events by the end of the century - just by virtue of having average sea levels be higher.

In terms of some of the other things that we need to look at, one thing that I think is going to be researched a lot is that this storm Sandy moved over very warm, unusually warm, waters in the North Atlantic. With a change in climate we absolutely expect ocean waters to warm. All things being equal, that does give a storm like Sandy more energy.

Of course, it's very difficult to say whether the warming this year was associated with climate change, but we can say that as the planet continues to warm we expect ocean temperatures to go up. And all things being equal, that would make storms stronger. Although there are other factors that can prevent storms from strengthening even as the planet warms.

GROSS: The polar ice caps are melting.

HORTON: Mm-hmm.

GROSS: Is that directly affecting the intensity of storms? Like, is there any connection you could make or would that be premature, inappropriate, to make a connection between those melting ice caps and a storm like Sandy?

HORTON: I think that given the dramatic changes that we've seen in sea ice in the Arctic in the last several years - we've got approximately half as much sea ice in the Arctic in the fall now as we did, say, 30 years or so ago. There's been this dramatic decrease.

There is emerging research. My colleagues and I published a paper last February on this suggesting that as that sea ice melts it's changing the jet stream, that sort of current that steers weather in the mid-latitudes places like New York. As sea ice melts, our research suggests that the jet stream is going to tend to get weaker.

As the jet stream gets weaker, it's easier for storms to stagnate or, in some cases, maybe even move to the west, which is what this storm did. Most hurricanes, as they get as far north as a place like New York - especially late in the season September, October - standard pattern is for that strong jet stream to push those storms to the east.

What we saw with this storm was that it moved to the west. It's a very unusual track, and I would say it's a big research question whether we might see in general more stormy weather and storms taking a track like that as sea ice melts. This is, again, a sort of unprecedented territory, so we do need more studies.

GROSS: Is the melting of the sea ice affecting the ocean level?

HORTON: The melting of sea ice in the Arctic has very little effect directly on ocean levels. Because you can think of it, really, as ice that's sort of already floating on water. As it melts it doesn't directly affect the sea levels. But there's emerging research suggesting that as the Arctic sea ice melts, it warms the atmosphere around it.

And so we need to look at these major ice sheets nearby, especially the Greenland ice sheet, and ask the question of whether the Greenland ice sheet is now experiencing warmer air, changes to maybe more rainfall events, instead of snow in some parts, and also warmer waters as that Arctic ice melts. Is that eroding some of the basis of these ice sheets on Greenland in ways that make it easier for the land-based ice on Greenland to sort of move to the water?

Because if your ice that's on land moves to the water then you do see an impact on sea level rise. That's emerging research but I think it's, you know, potentially a hazard that could contribute to sea level rise in the future.

GROSS: So how much did the science policy team of the New York City Panel on Climate Change that you serve on - how close did you come to predicting that this was going to happen? That a storm the strength of Sandy was going to happen and that it would have some of the destructive power that it did?

HORTON: I think the scale of this storm surprised everybody. Mayor Bloomberg, New York City, and many of the agencies took a very proactive role in preparing for climate hazards and climate change. But this was a huge storm. The timing of the surge, the amount of water that piled up above normal tide, that surge was at its biggest amount almost at precisely the same time that the normal high tide occurred.

So we got a real double-whammy with this storm. So I think that New York City was able to help prepare through some of the studies and proactive leadership of a few years ago. We got the types of impacts that we expected would happen at some time, but they happened, you know, on a very extreme scale that's, you know, very challenging to prepare for.

GROSS: Weren't you predicting the possibility of a storm that would flood the subway system?

HORTON: If we look at the historical record, the guidance is that roughly every 100 years or so you can get a storm that can flood parts of the subway system. If we look back at some of the historical storms, they sort of got close to but didn't quite really flood the subway system. This one was, you know, a couple feet or more higher than those past storms so it really pushed us into really sort of uncharted waters and a major, major challenge.

GROSS: If you look at the storm and the impact it's had on New York's infrastructure - electricity, subways, water supply - what are some of the lessons, first about climate change, but also about infrastructure and what needs to be done differently in an era of climate change and an era of increasingly intensifying storms? Before you answer that, is anything I've just said incorrect?

HORTON: No. I think you posed a good question. I might decompose it into sort of focusing on the impacts and then talking about how we might prepare and try to reduce those impacts. We do have a teachable moment here in the wake of Hurricane Sandy in many ways.

One of the ways is because this is an unprecedented event, you know, we're learning a lot, tragically, about the many different types of impacts that the storm can have. Clearly, the subways are the place to start. You know, we have several major tunnels with a huge amount of water in them. Pumping that water out is going to take time.

And even once that water is gone, this is salt water. Salt water and electricity do not mix. So, it's going to take a lot of time to test some of the electrical signal equipment, for example, and in some cases probably replace damaged electrical equipment.

We also know that, you know, there were major electrical distribution stations in the flooded areas, so power is likely to be out, you know, for quite a while. Other infrastructure that's been damaged includes communications, cell phones, Internet; everything right down to individual buildings, especially where there might've been electrical equipment in basements.

I think in terms of, you know, maybe some of the possible surprises of what we're seeing are areas that need to be researched more in the wake of this storm. One, I think that's emerged is this vulnerability to fires in some of these coastal areas. Is that something that we fully understood? And other steps that can be taken to sort of augment these heroic efforts that we saw from the firefighting community, for example, at Breezy Point in the wake of that fire.

And then another one to think about, I think, is New York's and the Northeast in general's, industrial legacy. There's a long history, much of it going back to before, you know, times of regulation of industry. We know there are some hazardous materials in soils, not just in New York but really along this industrialized coast, and I think moving forward we just need to research and see if some of the hazardous materials and soils did get into water, flood water.

And if it did, are there, you know, steps we can take in advance of the next storm to try to prevent that from happening again?

GROSS: So, listen, as the lead for the science policy team of the New York City Panel on Climate Change, do you feel like you helped prepare the city in any useful way for what it's coping with now?

HORTON: I think that it was a major effort to really get a whole group of agencies, private sector companies, to the table. And there was a role for experts - everything from climate scientists to risk management experts, members of the insurance community, for example. And I think as a result of that process, New York City did document some of the key vulnerabilities and took some specific adaptation steps as well.

Not adaptation as a process, but some of the key steps that were initiated included beginning the process of elevating some of the key infrastructure, including a waste water treatment plant in the Rockaways. You're also seeing a push in the last few years towards the sort of green infrastructure solutions to try to capture rainfall, flood waters, and also along the coast, to sort of buffer the coast through building up of marshes and such to limit the effects of storm surges.

GROSS: Dr. Horton, thank you so much for talking with us.

HORTON: Thank you.

GROSS: Dr. Radley Horton is with the Center for Climate Systems Research at Columbia University's Earth Institute and is a leader of the science policy team of the New York City Panel on Climate Change.

(SOUNDBITE OF MUSIC)

GROSS: You can download podcasts of our show on our website, freshair.npr.org and you can follow us on Twitter @nprfreshair and on Tumblr at nprfreshair.tumblr.com. Transcript provided by NPR, Copyright NPR.

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