Ecocentric

Population Plus Climate: Why Coastal Cities Will Face Increased Risks From Floods

A new study names the global cities most at risk at coastal flooding—both today, and in a warmer future.

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Aby Baker/Getty Images

Flooding seen at the entrance to FDR Drive in New York City after Hurricane Sandy, on Oct. 30, 2012

Living in New York, it’s easy to forget that the ocean is right on our doorsteps. This isn’t Miami with its beaches or Venice with its canals or New Orleans with its history of storms and floods. New York has always been a supremely self-involved city—this famous magazine cover pretty much sums it up—and though Manhattan is an island, it’s one that has its eyes turned inward, not out toward the water that rings it.

Hurricane Sandy ended that illusion last year. The storm surge flooded tunnels, subway lines and apartment buildings; swamped power lines and transformers caused a blackout over much of Manhattan that lasted for days. Altogether Sandy cost the city of New York some $19 billion in public and private losses, nearly all of it due to the water. Sandy wasn’t even that powerful a storm, its winds barely ranking as a category 1 when it made landfall along the East Coast last October. What it had was something any New Yorker who’s hunted for apartments could appreciate—location, location, location—hitting the biggest city in America and flooding it with all that forgotten coastal water.

For coastal cities like New York, Hurricane Sandy was a coming attraction for what is likely to be a very wet and destructive future. According to leaked drafts of the forthcoming new report from the Intergovernmental Panel on Climate Change (IPCC), scientists believe that sea level could rise by more than three feet by the end of the century is carbon emissions keep growing at a runaway pace. And a new study published in the journal Nature Climate Change laid out the enormous flood losses that major coastal cities could face in the future. Average global flood losses could rise from approximately $6 billion per year in 2005 to $60 to $63 billion per year by 2050, thanks to population and economic growth along the coasts and the multiplying effect of climate change-driven sea level rise. As Robert Nicholls, a professor of coastal engineering at the University of Southampton in Britain and a co-author of the study, put it in a statement: “There is a pressing need to start planning how to manage flood risk now.”

The Nature Climate Change study looked at both present and projected future flood losses in the 136 largest coastal cities in the world, looking at their financial risks both in absolute terms—taking into account protections like sea walls and dikes—and as a percentage of the city’s GDP. The cities ranked as most at risk today range from Guangzhou in southern China to Mumbai in India to, yes, New York City. What those cities tend to have in common is high wealth and population levels and relatively little flooding protection. (By contrast, Dutch cities like Amsterdam or Rotterdam—which are extremely flood-prone geographically—aren’t found on the list because the Netherlands government has invested heavily in coastal protection.) Three American cities—Miami, New York and New Orleans—are responsible for 31% of the total losses across the 136 cities surveyed in 2005. When it comes to losses as a percentage of total city GDP—which gives the very richest cities like New York an advantage—Guangzhou, New Orleans and Guayaquil in Ecuador are most at risk.

The situation changes a bit in 2050. The study assumed that climate change will lead sea levels to rise 0.65 to 1.3 ft. by 2050, with some cities facing additional sea level rise because of local subsidence—literally, the earth sinking. Developing cities like Guangzhou, Mumbai and Shenzhen face the biggest risks, though Miami and New York rank highest among cities in developed nations. If no improvements are made in flood defenses, the study estimates that the world could be facing as much as $1 trillion or more per year in losses. Now, that number is the worst of the worst case, assuming that cities do absolutely nothing to protect themselves from sea level rise, suffer major floods and then pay to immediately rebuild everything they lost. But even assuming improvements in coastal defenses, potential losses will increase significantly, thanks to the risk of bigger floods and more immediately, a huge increase in the number of people and the value of property along the coasts.

That second bit is important. It’s vital for governments to gain a better understanding of flooding risks from global warming—and sea level rises of the sort apparently projected by the IPCC will endanger major world cities. But the most immediate threat is the sheer increase in people—and their property—put in harm’s way in coastal cities. In the U.S. 87 million people now live along the coast, up from 47 million people in 1960, and globally six of the world’s 10 largest cities are on the coast. Of the $60 to $63 billion in flood risk the Nature Climate Change study estimates the world’s cities will face by 2050, $52 billion is due to economic and population growth—the rest is due to sea level rise and land use change.

That doesn’t mean that climate change-amplified floods and storms don’t present a danger to coastal cities—or that we don’t need to worry about reducing carbon emissions. But the numbers don’t lie—the single biggest increase in the risk from flooding comes from putting people and property in places where floods have always been likely to happen. As Sandy showed, coastal cities are at risk from major flooding right now if a storm should hit at the wrong place at the wrong time. It’s location, location, location—which is why it’s so important to spend money now to improve coastal defenses. We don’t have to wait for climate change to come.

47 comments
EsraGC
EsraGC

Not only these cities written above have risks. Also many cities in EU are under that risk .

I don't think  that there is gonna be a serious step to stop it till many people will die....

Pat_Keating
Pat_Keating

Why can't Schumer-Rubio-Obama, get it through there thick heads-----American's don't want 33 million more Mexican's!!  Most of them are poor & will end up on Welfare & food stamps at taxpayers expense!!!!  We need to vote these three idiots out of office!!  Anyone who thinks millions of poor people will help our economy belongs in a insane asylum!  That's why I keep saying we need just about everyone in our government replaced-----STARTING  WITH THE WHITE HOUSE!!!!  The Senate, and Congress!!!

bernelleg
bernelleg

the Schumer-Rubio-Obama immigration would double legal immigration and speed up the doubling of U.S. population. Seventy percent of likely U.S. voters believe that would worsen quality of life in the United States.

SkookumMaguire
SkookumMaguire

Population growth is the problem.  It drives man's contribution to climate change and everything else.

JamesBowen1
JamesBowen1

Climate change, while in itself is an enormous ecological problem, is not the fundamental ecological crisis facing the human race.  That distinction belongs to overpopulation.  In the U.S., overpopulation is being driven by immigration, including legal, illegal, temporary, permanent, and immigrant fertility.  The U.S. can best help to solve the overpopulation problem by reducing all immigration to levels that will not contribute to overall population growth, completely crack down on illegal immigration, end birthright citizenship, and overhaul our foreign aid programs such they family planning becomes their primary focus.  With the problems we are facing, the Senate Bill S.744, which grants amnesty to almost all illegal aliens in the U.S., doubles legal immigration, and greatly expands temporary immigration, is nothing short of insane.

gombey100
gombey100

The **MAJORITY** of Americans do NOT want this so-called Amnesty under the present conditions in this country - where there are over 20+ million citizens who are struggling because of unemployment and under-employment!!! This is nothing but POLITICS and Mcshame and Flake should be thoroughly ashamed of themselves to be backing this **DEAD-HORSE**!!

It is time to vote both these RINO Senators out-of-office and put people into the Senate who will respect the "wishes" of Arizonans!! McShame should have retired years ago as he is past his sell-by date!!

Incidentally, only 24 percent of Americans support the Schumer-Rubio-Obama provisions to grant work permits to illegal workers before enforcement measures are in place and this "Political" bill would increase permanent work permits for new immigrant workers from 10 million over the next decade to 20 million? Can the country truly afford that scenario??? I THINK NOT!!

As I previously stated...Mcshame and Flake do NOT represent the MAJORITY of opinions of Arizonan's and Americans in general!! Vote them both out-of-office ASAP!!! This is NOT over until the "Fat Lady" sings and she is just getting warmed-up!! Think very seriously about it - if the *Republic* means anything to you and your children's future!!!

dhughes0941
dhughes0941

As populations increase so does the trash and debris, resulting in an unhealthy environment.  Economic growth does impact public health without question.  What is most distressing, is corporate and government's lack of concern for the health of our environment to include animal welfare.  Exploitation for dollars is the the name of the game, that is the only priority.

ErikKengaard
ErikKengaard

I we didn't have so many people, there would be more room on higher ground, still near the coast.

ErikKengaard
ErikKengaard

". . .  why it’s so important to spend money now to improve coastal defenses?" I'm not at all in favor of my tax dollars going to coastal defenses against flooding. Let people who choose to live there pay for it.

ErikKengaard
ErikKengaard

". . .  why it’s so important to spend money now to improve coastal defenses?"What utter nonsense. What's vital is to stop population growth so fewer people live near the coasts. Growth can be stopped by stopping immigration.

sickbirds
sickbirds

Most of us already know that illegal aliens are causing problems for us medically, economically, educationally and  socially. Now we can add climate change due to overpopulation.

Most of the population increases over the past 50 years have been due to immigration, both legal and illegal.

And now some in our government want a Comprehensive illegal alien amnesty for the 11 to 18 million illegals, and little or no improvement in keeping out more of these criminals in coming years.

On top of this, the current Amnesty bill that the senate passed wants to open the doors to millions of guest workers and more immigrants.

More illegals; more greenhouse gases, more climate change.

Our country is doomed if we don't act now to deport all of the illegal aliens, stop the millions more lined up to come in illegally, and the governments plans to allow millions in to take our jobs and use our tax money to their own advantage.

ToddLittle
ToddLittle

Stop all immigration.  period.  Start sending these arabs that claim refuge, back where they came from.  they are a threat to national security here in the United States

natskvi
natskvi

In the U.S., population increases are driven by a single factor: immigration, mostly illegal.  The Senate is trying to pass the Schumer-Rubio-Obama bill that will double immigration.  Unless a moratorium is placed on legal immigration, illegal immigrants are deported, and illegal immigration is stopped, Americans will find themselves eventually living in Third World squalor conditions.

dholzman1776
dholzman1776

Aiding and abetting climate change: mass immigration to the United States. The average immigrant's greenhouse emissions rise fourfold after arrival here (Center for Immigration Studies, 2008). The reason is simple: most immigrants come from low ecological footprint countries, and we're the major industrialized nation with the biggest footprint, and the greatest per capita greenhouse emissions. The Gang of 8 bill would have added three New York States' worth of immigrants in just the first 20 years. Moreover, the US population has been exploding--from 248 million just 23 years ago to 315-320 million today--growth equivalent to more than three New York States. And three quarters of that growth has come from mass immigration. 

The extra greenhouse emissions will make the flooding worse in places like New York and Miami. Yet, our political leaders ignore this problem. 

jmcdtucson
jmcdtucson

Gee, no mention of immigration as the sole driver of U.S. population growth?

ErikKengaard
ErikKengaard

@jmcdtucson - Right. That wouldn't be the message those who pay for these articles want people to hear.