Study predicts sea level rise may take economic toll on California coast

Sep 13, 2011
This is a map showing the areas likely to be affected by upland erosion at Ocean Beach, San Francisco, following a range of sea level rise scenarios. The map shows Ocean Beach between Sloat Boulevard to the south and Lincoln Way to the north. This forecast was part of a new state-commissioned study conducted by economists at San Francisco State University examining the economic impact of sea level rise in California.

California beach towns could face hefty economic losses caused by sea level rise in the next century, according to a new state-commissioned study conducted by economists at San Francisco State University. The study forecasts the economic impact of sea level rise on five communities: Ocean Beach in San Francisco; Venice Beach and Malibu in Los Angeles; Carpinteria in Santa Barbara County; and Torrey Pines State Reserve in San Diego County.

Funded by the California Department of Boating and Waterways, the study examines the cost of coastal storm damage and erosion, both of which are expected to increase as sea levels rise. It also forecasts the economic impact of sea level rise on tourism and , as beaches that have been narrowed by erosion lose their appeal to visitors and their ability to sustain wildlife.

The results suggest that visitor hotspots like Venice Beach could lose up to $440 million in tourism revenue between now and 2100 if sea levels rise by 4.6 feet (1.4 meters), a projection specific to the California coast, based on recent scientific studies. At San Francisco's Ocean Beach, accelerated erosion could cause up to $540 million worth of damage.

"Sea level rise will send reverberations throughout local and state economies," said Philip King, associate professor of economics at San Francisco State University. "We also found that the economic risks and responses to a changing coastline will vary greatly over time and from beach to beach."

The findings suggest that the cost and type of damage will vary depending on a community's economy, geography and local decisions about land use. For example, if sea level rises by 4.6 feet, Malibu beaches could lose almost $500 million in accumulated tourism revenue between now and 2100. Revenue losses would be much smaller at San Francisco's windswept Ocean Beach ($82 million), which attracts fewer visitors per year.

In addition to mean sea level rise, the study estimated the economic impact of more extreme flooding. Coastlines are already at risk of low-probability coastal storms -- like 100-year floods -- but higher sea levels are expected to extend the depth and reach of these floods, increasing the damage to homes, businesses and public infrastructure.

"In California, our coastline is one of our most valuable natural resources," King said. "More than 80 percent of Californians live in coastal communities, and California's beaches support local economies and critical natural species."

King and co-authors Aaron McGregor and Justin Whittet hope the findings will inform local planning efforts to evaluate and respond to sea level rise. "Understanding the kind of impact sea level rise will have is important for deciding what adaptive action to take," King said. "Seawalls have become the de facto policy for dealing with erosion and sea level rise but our findings suggest that other policies such as beach nourishment or where possible, allowing the coastline to retreat, could be more cost effective."

King and colleagues conducted their analysis primarily using secondary data, an approach which allowed them to calculate the economic impact of sea level rise at a fraction of the cost and time taken to complete the more commonly used shoreline hazard assessments.

Below is a summary of the key findings:

Ocean Beach (north of Sloat Boulevard), San Francisco County

Based on a sea level rise estimate of 4.6 feet (1.4 meters) by 2100, Ocean Beach could lose:

  • $19.6 million in damages caused by a 100-year coastal flood damaging homes and contents. This is an increase of 200 percent from the present day risk of a 100-year flood, which is $6.5 million
  • $82 million in tourism spending and local and state tax revenue losses (accumulated between now and 2100) caused by a narrower, eroded beach attracting fewer visitors
  • $16.5 million in habitat and recreation losses, caused by erosion reducing the beach area by 92 percent (53 acres lost). Ocean Beach provides a habitat for native species such as the Western Snowy Plover, a bird that is federally listed as a threatened species
  • $540 million caused by land, buildings and infrastructure being lost or damaged by erosion and subsidence
Venice Beach, Los Angeles County

Based on a sea level rise estimate of 4.6 feet (1.4 meters) by 2100, Venice Beach could lose:

  • $51.6 million in damages caused by a 100-year coastal flood damaging homes, commercial buildings and contents
  • $439.6 million in tourism spending and local and state tax revenue losses (accumulated between now and 2100) caused by a narrower, eroded beach attracting fewer visitors
  • $38.6 million in habitat and recreation losses, caused by erosion reducing the beach area by 16 percent
Zuma Beach and Broad Beach, Malibu, Los Angeles County

Based on a sea level rise estimate of 4.6 feet (1.4 meters) by 2100, Zuma Beach and Broad Beach could lose:

  • $28.5 million in damage caused by a 100-year coastal flood damaging homes, commercial buildings and contents
  • $498.7 million in tourism spending and local and state tax revenue losses (accumulated between now and 2100) caused by narrower, eroded beaches attracting fewer visitors
  • $102.3 million in habitat and recreation losses caused by erosion reducing the beach area
Carpinteria City and State Beach, Santa Barbara County

Based on a rise estimate of 4.6 feet (1.4 meters) by 2100, Carpinteria City and State Beach could lose:

  • $10.7 million in damages caused by a 100-year coastal flood, damaging homes and contents, and commercial structures
  • $164.7 million in tourism spending and local and state tax revenue losses (accumulated between now and 2100) caused by a narrower, eroded beach attracting fewer visitors
  • $31.3 million in habitat and recreation losses caused by erosion reducing the beach area
  • $300,000 caused by upland areas being lost or damaged by erosion and subsidence
Torrey Pines City and State Beach, San Diego County

Based on a estimate of 4.6 feet (1.4 meters) by 2100, Torrey Pines City and State Beach could lose:
• $5 million in damages caused by a 100-year coastal flood, including damage to homes and contents, cars and roads
• $99 million in tourism spending and local and state tax revenue losses (accumulated between now and 2100) caused by a narrower, eroded beach attracting fewer visitors
• $20.2 million in habitat and recreation losses caused by erosion reducing the beach area by 100 percent
• $348.7 million caused by land, road and railway lines being lost or damaged by erosion and subsidence, including damage to the Los Angeles-San Diego-San Luis Obispo (LOSSAN) Rail Corridor

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User comments : 9

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Nanobanano
3 / 5 (5) Sep 13, 2011
They haven't seen anything yet.

If temperatures rise as projected, they'd need to account for the fact that East Pacific tropical cyclone season would be much longer and over a broader area, and tropical cyclone remnants would arrive in California perhaps a half category to a category stronger than historical norms (in a 30 year period centered on 2100, for example vs the existing historical norms.)

Inland flooding events would be much stronger and more frequent, AND because sea levels would be higher, the mouths of rivers and streams would back up much more quickly during any fresh water flood, causing river flooding not just in the valleys at the base of hills and mountains, but also additional flooding in the coastal regions.

Because mortgages tend to be for 30 years, the reality is all of our coastal regions need to be re-zoned and reallocated. Sea level rise will begin to be locally catastrophic, even on a "good" day, some time in the next 30 years.
Nanobanano
3.3 / 5 (3) Sep 13, 2011
Long Island, the Outter Banks in the Carolinas, and all other barrier islands need build bans IMMEDIATELY.

All mainland coastal regions within the projected sea level rise regions for 2100 need "build at your own risk" laws, Immediately, in which FEMA and state and local government assistance should be denied to anyone building new homes or businesses in these locations. Why? Because if the sea level is going to rise 37 to 55 inches in the next 90 years, then that easily places all of these locations well below the 100 year flood mark, in many cases even well below projected mean sea level within 100 years or less, and that doesn't even count storms, that's just projected mean sea level.

The erosion and inundation from this sea level rise would be like a 60mph tropical cyclone parked on location non-stop, forever...

This means these locations do not meet what the building and zoning codes reasonably require for the lifetime of the structure, even on a "Good" day...
Nanobanano
3.7 / 5 (3) Sep 13, 2011
Houston needs to start planning a NOLA style levee protection system now, just to buy time to re-locate the parts of the city that are doomed.

The greater NOLA area, Atchafalaya basin, Tampa, and Key West will all need to be abandoned, they are unsalvageable.

Shanghai? Goner.

I don't know what people are going to do really, because building a megalopolis or even metropolis scale city from the ground up takes longer than 100 years, and the U.S. alone will have at LEAST 8 metropolis scale cities that will be partially or totally destroyed in the Gulf and Atlantic coast alone, not counting smaller towns, villages and cities.

Irene? Pah, the water will be almost that high in some locations...permanently, on a calm day...

All those small and medium cities and towns at the backs of the bays behind the outer banks? Goner.

Of course most of us won't live to 2100, but most ADULTS 20 to 30 years old will live to see 12 inches or more of sea level rise.

Somebody DO SOMETHING.
nxtr
not rated yet Sep 13, 2011
the singularity will wipe out mankind by 2050 so don't worry - be happy...til then.
Decimatus
5 / 5 (1) Sep 14, 2011
90 year projections on the financial losses these properties could face due to rising tides?

Get real.
Sin_Amos
not rated yet Sep 14, 2011
Start planting rainforests on the coasts. It is so simple it might destroy your mind. The natural storm breaks will correct the issue. The Southern California coast is all concrete. Don't even get me started on NY. Google map it and chuckle. They will learn.
Nanobanano
not rated yet Sep 14, 2011
Start planting rainforests on the coasts. It is so simple it might destroy your mind. The natural storm breaks will correct the issue. The Southern California coast is all concrete. Don't even get me started on NY. Google map it and chuckle. They will learn.


Irene hit NY as a tropical storm; admittedly, an abnormally large and abnormally low pressure tropical storm, but still, not even a category 1 hurricane.

The water went right up to the flood walls, and in some cases over-topped them by several inches.

Multi-million dollar simulations have been done, and found that a legitimate Category 3 strike on NY even at present day sea levels would be catastrophic.

If these sea level rise projections are accurate, that means the water in an exact repeat of Irene, a "mere" tropical storm when it hit NY, in 2100 will be 4.6 feet higher.

An inch of water over a sea wall today, vs 4.6 feet of salt water flowing into buildings and destroying the subways in 2100.
Nanobanano
not rated yet Sep 14, 2011
And then since average global sea temps will be around 3c hotter, NY (at least Long Island anyway since it sticks out,) will actually be threatened by "weakening" category 4 and 5 hurricanes, and potentially hit by category 2 and 3 hurricanes "often" compared to modern statistics!

http://www.ssd.no...rgb.html

The mid atlantic is mid lattitude, so it's mean sea temp rise should be similar to the global average, in theory.

So click on "SST" and look. Add 3C to the 24C isotherm, and viola, you have a 27C isotherm, that's enough to form POP UP category 1 and 2 hurricanes right off the coast of Delaware and New Jersey! Nevermind the "normal" powerful stuff that comes from the Cape Verde region, like Irene.

For an othewise exact repeat of the otherwise same conditions, if you have 3c higher average SST, you can just go ahead and add 20mph to the storm's sustained wind speed along it's entire track.
kparky
1 / 5 (1) Sep 15, 2011
Swedish geologist and physicist Nils-Axel Morner, formerly chairman of the INQUA International Commission on Sea Level Change, has stated "all this talk about the sea rising is nothing but a colossal scare story".
Despite fluctuations down as well as up, "the sea is not rising," he says. "It hasn't risen in 50 years." If there is any rise this century it will "not be more than 10cm (four inches), with an uncertainty of plus or minus 10cm". The economists estimates are based on a sea level rise estimate of 4.6 feet (1.4 meters) by 2100.
If the "University Economists' findings were based on "secondary data" from the IPCC's last two reports, you might be interested to know not one of the IPCC's 22 contributing authors on sea levels was a sea level specialist.
'Garbage in Garbage Out'.............
Glad my tax dollars aren't paying for this!

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