Cue sounds of timpani, stage left and stage right. A couple of weeks ago, I wrote a drum-banging post about coastal management myopia; now, recent reports compel me to continue my instrumental activity. So let’s think a little about the implications of rising sea levels (emphasis on the word think).
It is a fact (which I choose to define as something supported by observation, measurement, and analysis – in other words, science) that sea levels have been rising and it is reasonable to infer that this will continue. The world is, in general, warming, and the laws of physics (if you choose to accept them) require that warming oceans expand in volume; the cause of the warming, and any so-called debate over human influence, is irrelevant. Expanding ocean volumes have to go somewhere, and that somewhere is, inevitably, low-lying coastal land. OK so far? Anything really to challenge here? Those questions are, of course, essentially rhetorical since I have good reason to believe that readers of this blog are capable of independent, rational thought. Now here’s the tricky bit: predicting the magnitude of future sea level rise at any place on the planet is not easy – there is (oh dear) some uncertainty associated with this. But perhaps we can, nevertheless, attempt to come to grips with this uncertainty, and plan accordingly? Unfortunately, the answer seems to be “no.”
In that previous post, I mentioned NC20, the lobbying organisation of twenty North Carolina counties, who declare that they “concentrate primarily on actions to prevent regulation and rule making not based on science.” That statement would imply that, in turn, they would support regulation that is based on science, yes? No. When presented with a report by the North Carolina Coastal Resources Commission (CRC) in which a group of nineteen scientists presented an assessment of sea level rise, the response by the NC20 Board Members (credentials) was as follows:
Perhaps the most impressive accomplishment to date was the complete reversal of the draft policy of CRC regarding Sea Level Rise (SLR). The draft policy presented by the Science Panel of the CRC mandated a planning component of 39 inches of SLR across the CAMA area. NC 20 Board members met in a private meeting with the Chair of the CRC and carefully laid out the unscientific assumptions used in the draft report, showing the numerous errors and inconsistencies. In the final presentation, all “mandates” were removed and the final document showed a sensitivity to the needs of the counties, the role of the CRC, and the need for a relationship characterized by scientific advice and assistance on the part of the CRC rather than ironfisted dictates. The “redlined” version of that final document is attached for your review.
Follow the link and you will see the original policy wording (deleted) and its replacement (I shall resist commenting):
And here, just for a laugh, are the "unscientific assumptions" on North Carolina sea-level rise (taken from the CRC report):
So this really is about noise: the decibels from the drumbeats and grinding axes of vested interest lobbying easily drown out the voices of nineteen scientists.
But for those who heroically maintain an interest in science and how it can inform planning and economics, let’s turn to the couple of recent reports that I mentioned, that address exactly this topic. First, there has been a fair level of justified (but not particularly cacophonous) buzz in the media about a report from Climate Central titled Surging Seas: Sea level rise, storms, and global warming’s threat to the US coast, published on the 14th March, simultaneously with the research being published in the peer-reviewed journal Environmental Research Letters. Two pieces from the New York Times (grounds, I sadly realise, for them to be dismissed), one by Andy Revkin, the other by Justin Gillis, summarise the findings from the report. As Revkin quotes from the report, which makes it clear that it is not simple sea level rise itself, but associated storm surges that represent the threat:
Rising seas dramatically increase the odds of damaging floods from storm surges. For over two-thirds of the locations analyzed (and for 85% of sites outside the Gulf of Mexico), past and future global warming more than doubles the estimated odds of “century” or worse floods occurring within the next 18 years — meaning floods so high they would historically be expected just once per century. For over half the locations analyzed, warming at least triples the odds of century-plus floods over the same period. And for two-thirds the locations, sea level rise from warming has already more than doubled the odds of such a flood even this year….
Sea level rise has already cost governments and private landowners billions of dollars as they have pumped sand onto eroding beaches and repaired the damage from storm surges.
Insurance companies got out of the business of writing flood insurance decades ago, so much of the risk from sea level rise is expected to fall on the financially troubled National Flood Insurance Program, set up by Congress, or on state insurance pools. Federal taxpayers also heavily subsidize coastal development when the government pays to rebuild infrastructure destroyed in storm surges and picks up much of the bill for private losses not covered by insurance.
For decades, coastal scientists have argued that these policies are foolhardy, and that the nation must begin planning an orderly retreat from large portions of its coasts, but few politicians have been willing to embrace that message or to warn the public of the rising risks.
Some further selected key points:
- By 2030, storm surges combined with rising seas could raise waters to 4 feet (1.2 metres) or more above high tide lines at many locations; 4.9 million people live in 2.6 million homes in this vulnerable zone between the observed high tide and the top of expected flood waters.
- In 285 coastal cities and towns, more than half the population lives below the 4-foot mark, the Climate Central report found. Florida has 106 of these at-risk municipalities; Louisiana has 65, New Jersey and North Carolina have 22 each, Maryland has 14, New York has 13 and Virginia has 10.
- For two-thirds of the locations, sea level rise from warming has already at least doubled the annual risk of century-plus floods.
- The population and homes exposed are just part of the story. Flooding to four feet would reach higher than a huge amount of dry land, covering some 3.0 million acres of roads, bridges, commercial buildings, military bases, agricultural lands, toxic waste dumps, schools, hospitals, and more.
And a couple of quotes from Ben Strauss, one of the lead scientists authoring the report:
Sea level rise is like an invisible tsunami, building force while we do almost nothing. We have a closing window of time to prevent the worst by preparing for higher seas….
A lot of the state [of Florida] is built on porous bedrock, bedrock that's like Swiss cheese. You can't practically build a wall to keep the sea out. The water will come up through the ground….
Right now the projection for the end of the century is two to seven feet of sea level rise and seven feet would put a lot of Lower Manhattan under water if we didn’t build sea walls to protect it.
So, if the Board of NC20 were to read this report, what would they find about their state? Well, the report’s website has an excellent interactive map, and a series of fact sheets on each state; here are some headlines for North Carolina:
- Odds of a 100‐year flood or worse by 2030, with sea level rise from global warming: 24% (odds without global warming: 9%)
- Historic local sea level rise rate: 0.8 inches/decade; projected new sea level rise by 2050: 11 inches
- Population at risk: 76,000
- Homes at risk: 56,000
- Land area at risk: 1.2 million acres
- Towns and cities where at least half the population is at risk: 22
- Counties where at least 10% of the population is at risk: 9
And then there’s the recently published study whose focus is on California; the study "Estimating the Potential Economic Impacts of Climate Change on Southern California Beaches," is featured in a special edition of the peer-reviewed journal Climatic Change, and is the work of researchers at Duke University. The study again looks at the effects of sea level rise in the long term, and the short term effects of storms. As reported in Science Daily last month:
While some beaches may shrink or possibly disappear, others are poised to remain relatively large -- leaving an uneven distribution of economic gains and losses for coastal beach towns, according to a study by researchers at Duke University and five other institutions.
"Some beaches actually stand to benefit economically from sea level rise, creating winners and losers among California beach towns," said Linwood Pendleton, director of ocean and coastal policy at Duke's Nicholas Institute for Environmental Policy Solutions. "We found, as relatively small beaches shrink more due to sea level rise, people will stop visiting them, opting for wider beaches."
The same topic was addressed last year in a report by economists at San Francisco State University that examined the economic effects of sea level rise and storms on five California coastal communities:
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."
Here, as an example, are the estimated impacts on San Francisco’s Ocean Beach:
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
The facts, the predictions, the costs, the social implications, are there to be found, whether the result of work by universities, government agencies, or – as I happened upon – even the real estate “community.” The property site, World Property Channel, published the results of a “Special report: Long Island, Miami Have Highest Property Exposure to Storm Surge Damage as Hurricane Season Approaches” that was accompanied by dramatic graphics and the following figures:
Of the metro areas studied in the report, Long Island was found to have the highest exposure to risk, valued at $99 billion, followed by the Miami-Palm Beach region and Virginia Beach. Projected exposure to storm surge damage for the ten geographies is as follows:
Long Island, NY - $99 billion, Miami-Dade, FL - $44.9 billion, Virginia Beach, VA - $44.6 billion, New Orleans, LA - $39 billion, Tampa, FL - $27 billion, Houston, TX - $20 billion, Jacksonville, FL - $19.6 billion, Charleston, SC - $17.7 billion, Corpus Christi, TX - $4.7 billion, Mobile, AL - $3 billion
But, silly me, I’m forgetting that all this work, all these “facts," are flawed by “unscientific assumptions… showing the numerous errors and inconsistencies.”
[Photographs: the surge before the storm swamps Galveston Island, Texas, and a fire destroys homes along the beach as Hurricane Ike approaches. (AP Photo/David J. Phillip). Flooding over access road 523 to Surfside beach, caused by Hurricane Ike forming in the Gulf of Mexico, is seen near Surfside Beach, Texas. (REUTERS/Carlos Barria). And http://myhydros.org/more-about-water/storm-surge/]