Habitat loss doubles coastal flood impact, study says

Jul 14, 2013
Marshland is seen on May 11, 2010 in Venice, Louisiana. Removing mangroves, marshes, reefs, forests, dunes and other natural defences doubles the risk for life and property from coastal floods, a US climate study said on Sunday.

Removing mangroves, marshes, reefs, forests, dunes and other natural defences doubles the risk for life and property from coastal floods, a US climate study said on Sunday.

In the most detailed analysis of the risks facing Americans from rising seas, researchers led by Katie Arkema at Stanford University in California built a of coasts in the continental United States.

The huge programme factored in , residential property values, natural defences and flooding probability on a scale of one square kilometre (0.38 of a square mile).

"Today, 16 percent of the US coastline comprises 'high hazard' areas harbouring 1.3 million people, (including) 250,000 elderly (and) 30,000 families below the , and $300 billion (230 billion euros) in residential property value," the study said.

This estimate is for current sea levels and for the current state of natural buffers against floods.

Strip away this protection in order to build on the land, and the number of people and the value of property at roughly doubles.

"At present habitats protect 67 percent of the coastline," said the study, published in the journal Nature Climate Change.

"Habitat loss would double the extent of coastline highly exposed... and the number of , elderly people and total property highly exposed to hazards would also double."

In addition, rising seas caused by global warming will drive up the exposure, the study warned.

The team calculated what would happen under a common scenario for warming, known as A2, under which Earth's average surface temperature would rise by 2.0-5.4 degrees Celsius (3.6-9.7 degrees Fahrenheit) this century.

Around two million people, and property worth some 500 billion, would be in "high hazard" areas—a red line that stretches around most of the Gulf and Atlantic coasts and parts of San Francisco Bay.

That exposure would almost double if habitat defences are removed, because more people inland are placed at risk.

Arkema says the new study can guide policymakers as to which areas are most exposed and which habitats are to be nurtured. Twenty-three of the United States' 25 most populated counties lie on the coast.

"The traditional approach to protecting towns and cities has been to 'harden' shorelines," the paper notes.

"Although engineered solutions are necessary and desirable in some contexts, they can be expensive to build and maintain, and construction may impair recreation, enhance erosion, degrade water quality and reduce the production of fisheries."

Experts have long pointed out the folly of building homes and businesses on exposed coast and stripping away natural shields against seas.

The message was given added weight after Superstorm Sandy swamped parts of New York and New Jersey in October 2012.

Last month New York Mayor Michael Bloomberg unveiled a $19-billion plan to build six-metre (20-feet) -high waterfront walls and dikes—and also reinforce or create dunes along vulnerable stretches of the city's coast.

Explore further: Mayor to discuss prepping NYC for warming world

More information: Paper: dx.doi.org/10.1038/nclimate1944

add to favorites email to friend print save as pdf

Related Stories

Mayor to discuss prepping NYC for warming world

Jun 11, 2013

(AP)—The projections paint an unsettling picture of New York's future: a city where by the 2050s, 800,000 people could be living in a flood zone that would cover a quarter of the land, with temperatures ...

Levees, removable walls in plan to protect NYC

Jun 11, 2013

(AP)—Mayor Michael Bloomberg is proposing removable flood walls for much of lower Manhattan, a permanent 15-to-20-foot levee in part of Staten Island and a system of gates and levees at a Brooklyn creek ...

Report: Fourth of NYC could be flood zone by 2050s (Update)

Jun 10, 2013

By the 2050s, more than 800,000 New York City residents could be living in a flood zone that would cover a quarter of the city's land and New Yorkers could sweat out as many 90-degree (32-Celsiu) days as is now normal for ...

Climate talk shifts from curbing CO2 to adapting

Jun 16, 2013

Efforts to curb global warming have quietly shifted as greenhouse gases inexorably rise. The conversation is no longer solely about how to save the planet by cutting carbon emissions. It's becoming more about ...

Recommended for you

US delays decision on Keystone pipeline project

Apr 18, 2014

The United States announced Friday a fresh delay on a final decision regarding a controversial Canada to US oil pipeline, saying more time was needed to carry out a review.

New research on Earth's carbon budget

Apr 18, 2014

(Phys.org) —Results from a research project involving scientists from the Desert Research Institute have generated new findings surrounding some of the unknowns of changes in climate and the degree to which ...

User comments : 0

More news stories

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

UN weather agency warns of 'El Nino' this year

The UN weather agency Tuesday warned there was a good chance of an "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughts and heavy rainfall to the rest of the world.

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...