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Sea Level Rise Could Be Three Times Worse Than Previous Estimates

November 14, 2019

A new study and mapping visualization tool by the organization Climate Central says hundreds of millions more people than previously thought live in coastal flooding risk zones.

A new study and mapping visualization tool by the organization Climate Central says hundreds of millions more people than previously thought live in coastal flooding risk zones.


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Story Transcript

GREG WILPERT: Welcome to The Real News Network. I’m Greg Wilpert in Arlington, Virginia.

Global sea level rise may be three times worse than originally projected; impacting hundreds of millions of people, particularly in Asia. That’s the conclusion of a new study and accompanying mapping tool created by the organization Climate Central. The study, published in the journal Nature Communications in late October, concludes that rising sea levels could create chronic floods that rise above sea level; impacting 300 million people within the next few decades. And by the year 2100, some 200 million people could be impacted by global sea level rise, destroying many of the world’s major coastal cities.

Sea level rise is the direct result of climate change and global warming. Higher global temperatures have led to the ongoing melting of Arctic ice caps, which in turn has led to a higher global sea level. But Climate Central’s new projections, which come from data gleaned via a machine learning tool, show that the issue could be even more dire than previous projections had shown.

Here to talk about the findings and their implications is Benjamin Strauss, the chief scientist and CEO of Climate Central. Climate Central is an independent organization of scientists and journalists researching and reporting the facts about our changing climate and its impact on the public. Thanks for joining us today, Benjamin.

BENJAMIN STRAUSS: Thanks so much for having me, Greg.

GREG WILPERT: So in my introduction I laid out the broad findings of your report, but let’s drill down a bit on the numbers and specifics. What exactly did you and your coauthors discover and how did you do so?

BENJAMIN STRAUSS: So the interesting thing about our research is we actually made no new projection about global warming or about sea level rise. What we did is we reevaluated the elevation of land where people live. If you need to understand the vulnerability of coastal populations to sea level rise, you really need two things. A forecast of how high the water level is going to be, but also an understanding of how high the land is. And the climate science community historically has been focused on the moving ball. What’s changing, which is sea level.

And our contribution was to recognize that the elevation data that the community had been using for global and international assessments is very flawed for this purpose, and in fact overestimates elevations by more than six feet, which leads to a false sense of security and safety. So we used artificial intelligence to develop a model that essentially eliminated that deficit from the elevation model. And we discovered that many more people, more than three times as many people live on land forecast to be vulnerable from rising sea levels and rising coastal flood levels over the coming decades.

Something else that’s really important to understand though about our research is that we’re not saying that the places below those levels will disappear or be erased. In some cases that could happen. But we don’t evaluate whether coastal defenses, existing coastal defenses or future coastal defenses may be able to protect those places. And in fact, we discovered that more than 110 million people, according to our data, live on land that is already below the high tide line globally. So when you look at that number, it can really come about for only two reasons. Either one, those people are already protected by levees or perhaps distance from the coast; or two, there is certainly error in our data. Although on average, we think it does a fine job.

There will be some locations where it may underestimate elevations, but our main view is that there are a great many people who are already protected to some degree by coastal defenses. And clearly there will be the possibility of improving those coastal defenses or building new defenses in the future. So we see this as a very significant threat for hundreds of millions of people around the world in the coming decades. But it doesn’t mean that they will all have to desert ship necessarily or or have have their cities erased, so to speak.

GREG WILPERT: Now, the study points out that Asia in particular, it could be hit hardest as a continent and that this of course has some of the most populous cities in the world. So for example, Shanghai and other major cities within China, it could be hit particularly hard. In total, you conclude that 151 million people are at risk for sea level rise in Asia alone and 43 million in China. Now, what factors contribute to that and do you see any efforts to address this potential crisis in the area of the world?

BENJAMIN STRAUSS: So, Shanghai is an interesting case in point. There are already levies in some of the area around Shanghai and I think work afoot to expand the levy network. So there is engineering happening to try and defend that place unsurprisingly. But of course, even if you build a levy, when it rains, the areas protected by that levy will be much more prone to flood because the water gets trapped in the inside by levees, even if you’re defending yourself against high tides. So the other side of the coin of what I was just saying about the potential for coastal defenses is a lot of… Asia doesn’t have the same level of resources as much of Europe and the United States and some other parts of the world.

So it’s not clear that there will be the financial resources to defend against rising seas in many places. And some places may also simply be impractical to defend because of their geography. That complexity of the coastline, the nature of the land. And one of my big fears and looking at our research results is, could sea level rise precipitate over time? A real crisis in terms of generating streams of migrants and internal displacements within nations or displacements among nations. Certainly I would hate to see political instability or regional conflict driven by rising seas and migrations, but that seems like a possibility for the coming decade, especially in such a densely populated place as Asia.

GREG WILPERT: Well, can you say a little bit more about that in terms of the refugees, the climate refugees that we could see? I mean, you lay out some of those statistics in your paper and also, how would this impact people within North America, either in terms of the flooding or in terms of refugees?

BENJAMIN STRAUSS: So, think back a few years ago to refugees leaving from Syria and fleeing to Europe and also leaving from Sub-Saharan Africa and the crisis that that was for Europe and how that upended a lot of politics in Europe. Well, that volume of refugees looks like a small trickle compared to what could be if sea levels rise rapidly and if communities and cities and countries aren’t able to either build defenses or find other ways to relocate people in a safe, fair means. So you really could have large volumes of refugees over time in a densely populated area. And I feared that that could really be destabilizing for politics and change all kinds of dynamics. And it doesn’t have to be that you’re flooded out of your house either.

If you think of places like the Mekong Delta, most of it is agricultural land and it’s very important for rice cultivation. Well, if chronic flooding starts to make the soil too salty to cultivate rice, suddenly you have a lot of farmers out of work and the roots of the Syrian conflict, in fact, we’re in a drought which basically pushed farmers off the land and into the cities and led to political instability. And ironically there were kind of fingerprints on that trip. So it’s not hard to imagine similar dynamics coming into play across Asia, which is much more densely populated. There is so much to lose in Asia where farmers get pushed off their land because of a salinification, even before we talk about relocating villages or people having to move because of rising seats.

So I think that is really one of the most serious dimensions of sea level rise and where there are internal migrants and refugees and political tensions coming from them, I’m sure that that would increase the pressure from refugees who want to come to the United States as well. And obviously immigrants and refugees have become very contentious political topics in the United States. So I see sea level rise as potentially exacerbating those as well.

GREG WILPERT: Of course, the United States itself would not be unaffected by the sea level rise.

BENJAMIN STRAUSS: Absolutely not. Our study didn’t have anything new to say about the United States, I should be very clear. Because we already have very high quality elevation data in the U.S. and we have done analysis with those data. With the new research we published an interactive map on our website, @coastal.climatecentral.org, so anyone can go there and look at the global threat. But if you want the US threat, then it would be ss2.climatecentral.org. It’s another map and it’s another set of analyses, but from that earlier work, which really inspired the global work later on, absolutely.

There are communities across the United States which are suffering from sea level rise today. There are already some communities which are relocating and there are other places–often it’s pocket neighborhoods in cities up and down the Atlantic–where homes have lost most or all of their value. And residents have become financially trapped because they flood so frequently that they can’t sell the home. And they’re stuck dealing with floods that regularly destroy their first floor appliances and leave behind mold and all kinds of problems. So yes, it’s very real here in the United States as well.

GREG WILPERT: Now finally, before we conclude, how do you hope that these new findings of your study play into the discussions and planning around the issue of climate refugees and global migration patterns at the upcoming UN climate talks in Madrid?

BENJAMIN STRAUSS: Well, I hope that our study will underscore for the delegates that there’s a great deal more at stake than they might appreciated earlier. And it’s, I think, critical if we want to avoid profound problems and conflicts. It will be critical to begin planning and implementing measures early. Just as every day of warning we can get from a forecast of an incoming hurricane saves lives and property, every decade of warning we can get, to allow more time to prepare for sea level rise. Will, I believe, save communities, even whole cities and reduce the possibility of these very troubling potential conflicts that could ensue if sea level rise does cause large streams of refugees and migrants.

GREG WILPERT: Okay. Well, we’re going to leave it there for now. I’m speaking to Benjamin Strauss, the chief scientist and CEO of Climate Central and coauthor of the new study, New Elevation Data, Triple Estimates of Global Vulnerability To Sea-Level Rise And Coastal Flooding. Thanks again, Benjamin for having joined us today.

BENJAMIN STRAUSS: Thanks so much for having me.

GREG WILPERT: And thank you for joining the Real News Network.

DHARNA NOOR: Hey y’all. My name is Dharna Noor and I’m a climate crisis reporter here at The Real News Network. This is a crucial moment for humanity and for the planet. So if you like what we do, please, please support us by subscribing at the link below. Thank you.