USGS: In Next Decades, Frequency of Coastal Flooding Will Double Globally

from USGS, May 18, 2017

The frequency and severity of coastal flooding throughout the world will increase rapidly and eventually double in frequency over the coming decades even with only moderate amounts of sea level rise, according to a new study released today in “Nature Scientific Reports.”

[Readers, note that this press release does not mention the cause of sea level rise, i.e., atmospheric carbon dioxide pollution, and it only mentions, at the very end, "climate adaptation."  Nothing is stated about how sea level rise is expected to be 2 meters (over 6 feet) by 2100.]

This increase in flooding will be greatest and most damaging in tropical regions, impairing the economies of coastal cities and the habitability of low-lying Pacific island nations. Many of the world's largest populated low-lying deltas (such as the Ganges, Indus, Yangtze, Mekong and Irrawaddy Rivers), also fall in or near this affected tropical region.

The new report from scientists at the U.S. Geological Survey, the University of Illinois at Chicago, and the University of Hawaii shows that with just 10-20 cm (4-8 inches) of sea level rise expected no later than 2050, coastal flooding will more than double. This dramatic increase in coastal flooding results from rising sea levels combined with storm-driven flooding, including the effects of waves and storm surge.

Water-level components that contribute to coastal flooding.(Public domain.)

Wave-driven flooding and overwash on Roi-Namur Atoll, Republic of the Marshall Islands (Credit: Peter Swarzenski , U.S. Geological Survey. Public domain.)

Wave-driven flooding and overwash on Roi-Namur Atoll, Republic of the Marshall Islands (Credit: Peter Swarzenski, U.S. Geological Survey. Public domain.)

In most coastal regions, the amount of sea level rise occurring over years to decades is small, yet even gradual sea level rise can rapidly increase the frequency and severity of coastal flooding. Until now, global-scale estimates of increased coastal flooding due to sea level rise have not considered elevated water levels due to waves, and thus have underestimated the potential impact.

The researchers combined sea level projections with wave, tide and storm surge models to estimate increases in coastal flooding around the globe. They found that regions with smaller variations in ocean water levels due to tides, waves and storm surge, common in the tropics, will experience the largest increases in flooding frequency.

“Although it is commonly understood that sea level rise will increase the frequency of coastal flooding, most of that previous scientific work has focused on analyzing tide gauges which capture extreme tides and storm surge, but not wave-driven water levels. Tide gauge data exist only for a limited number of locations around the world. Using models rather than individual tide gauges provides a comprehensive picture of the widespread vulnerability rather than at sparse points where observed data exist,” said lead author of the study, Sean Vitousek, who was a post-doctoral fellow at the USGS when he began this study. Vitousek is now a professor in the Department of Civil & Materials Engineering at the University of Illinois at Chicago.

“The key findings are that areas with limited water-level variability, due to small tidal ranges (for example, the Tropics), and more limited ranges in storm water levels (such as the North American West Coast), will experience the largest increases in flooding frequency. In the Tropics, today’s 50-year water level event will occur every 5 years with just 10 cm of sea level rise,” said USGS geologist and coauthor, Patrick Barnard.

Most previous research has started with expected scenarios of sea level rise and attempted to find the flooding frequency increase. In this new study, the scientists took the opposite approach, finding the amount of sea level rise needed to double the frequency of flooding, while accounting for the uncertainty and year-to-year variability of storm patterns. One of the surprising findings was that it does not take much sea level rise to double the frequency of flooding (particularly in the Tropics). Using this analysis, Vitousek and his coauthors demonstrate that the 10 cm or less of sea level rise expected within the next few decades can more than double the frequency of coastal flooding for many locations across the globe. The areas with smaller increases in flood frequency include areas with very large tidal ranges and those along typical tropical storm paths.

“Most of the world's tropical atoll islands are on average only 1 to 2 meters above present sea level, and even in the high tropical islands such as Hawaii, Guam, American Samoa, U.S. Virgin Islands, Indonesia, and others, the majority of the population and critical infrastructure is located on a narrow coastal fringe at low elevations (1-2 m above present sea level) and thus susceptible to this increased flood frequency,” said USGS geologist and coauthor, Curt Storlazzi.

“These important findings will inform our climate adaptation efforts at all levels of government in Hawaii and other U.S. affiliated Pacific islands,” said coauthor Chip Fletcher, Associate Dean and Professor at the School of Ocean and Earth Science and Technology at the University of Hawaii.

The full report, “Doubling of coastal flooding frequency within decades due to sea-level rise,” is published online in Nature Science Reports.

https://www.usgs.gov/news/next-decades-frequency-coastal-flooding-will-double-globally

New Yorker: Insuring the Apocalypse

by McKenzie Funk, The New Yorker, May 15, 2014


Last week, the White House released the National Climate Assessment, and the news is grim. Coral reefs are dying, shellfish will increasingly make us sick, and cherries are being decimated by weather extremes. Along the Eastern Seaboard, waters will rise up to 4 feet—perhaps 6 feet—by the end of the century, making Sandy-like storm surges a frequent event. California will continue to burn. Arizona will continue to burn. For most businesspeople, climate change seems bad for the bottom line.

But if you, like Berkshire Hathaway C.E.O. Warren Buffett, work in the disaster business, reports like the National Climate Assessment, all 829 pages of it, are free advertising. In a recent television appearance, Buffett suggested that global warming—at least the idea of it—has been good for the insurance industry. “I love apocalyptic predictions on it because, you’re right, it probably does affect rates,” he told an interviewer. “The truth is that writing U.S. hurricane insurance has been very profitable in the last five or six years.”

Buffett’s insurance companies have yet to adjust how they calculate their exposure to hurricane risk, he explained, though “that may change in ten years.” They haven’t been hoarding more cash to prepare for bigger storms; they haven’t been cancelling policies. His point was not that climate science is a sham but that what it has mostly done—for now, for him—is to prop up revenues and bring in new customers.

By 2012, insurers had introduced 1,148 climate-change products and services in 51 countries, according to a review by the Lawrence Berkeley National Laboratory. If you’re an executive today, for instance, especially if your business emits carbon, you may be interested in a policy from Liberty Mutual that protects against what the company calls “the continuously growing wave of litigation stemming from the alleged improper release of carbon dioxide and other greenhouse gases.” If you’re poor and African, you may be interested in reinsurer Swiss Re’s early efforts to insure you and 400,000 of your compatriots against drought. A 2007 program promised an US$18 million climate-adaptation payout to subsistence farmers if the right “weather trigger” was hit, with premiums paid by international donors. 

In 2008, while investigating how the insurance industry was faring in a warming world, I rode into a series of suburban wildfires near Los Angeles with a fire chief who worked part-time for A.I.G., the giant insurer that was then on the verge of being bailed out by the federal government. The company operated a squad of private firefighters, and, as helicopters clattered overhead, members of the A.I.G. team mostly drove around in haphazard circles, checking on client homes and sometimes spraying them with a fire retardant. They snuck across police lines. They made sure that A.I.G. clients had been evacuated. They made sure that brush wasn’t too close to any A.I.G.-protected structures. They stopped to get tacos, sip sodas, and watch news about the fire on a taqueria’s television set. They exchanged uneasy glances with public firefighters. They parked their trucks on a residential street for the better part of an hour and watched the public guys battle the blaze. The privateers didn’t do much good that day—not even for their own clients—but they made good money.

A boutique firefighting service is just one way that the insurance company attracts “high net worth individuals” to its private-client group. Another way, available in parts of Florida, New Jersey, New York, Massachusetts, and South Carolina, is its hurricane-protection unit: a jump team of contractors that arrives at your house armed with tarps and hammers, racing to beat looters and rain. If there are any holes, it patches them. If your expensive paintings or sculptures are threatened, it evacuates them.

The National Climate Assessment is, in fact, just what Buffett suggests: an argument for more insurance. As we face the future, insurance can help us grapple with the true cost of the present—something that we’ve largely proved incapable of doing by ourselves.

Outside of government agencies, the insurance industry is the primary funder of climate-change research. A trade group is sponsoring studies on how climate change affects tornadoes and hail. Another is backing university research on land ecosystems in a warming world, especially forests and crops. A British company is focusing on hurricane intensity and temperature rise, while an insurer in Bermuda researches cloud seeding to see whether the storms can be stopped before making landfall. A.I.G., for example, just released a climate report of its own, noting “a disproportionate increase in the number of extreme weather events” in North America. Buffett is right: in 10 years, if not sooner, calculations are bound to change. Those paying for the best research will get it first and, when they see an immediate risk, they’ll immediately price it in. For their own survival and for the sake of their shareholders, they will have to. Insurance rates will go up. And, if the risk is deemed too high or regulators block massive rate increases, as took place in coastal Florida some years ago, insurers will exit the market.

If profits equal progress, however, the insurance industry is on the right track. While researching a book that I wrote on the topic, I found that, when Hurricane Andrew landed in Florida and Louisiana, in 1992, insurers were caught unprepared, disbursing $1.27 in claims for every dollar of premium earned, for a total of US$23 billion. Those insurers started paying attention, and raised rates accordingly. Total claims were almost twice that when Hurricane Katrina hit Louisiana 13 years later—but insurers still came out ahead, losing just 71.5 cents per dollar of premium. Industry profits were US$49 billion that year. We continue to gamble with our environmental policies. But the insurance industry, year after year, keeps winning. [Until they don't, and go away.]

http://www.newyorker.com/online/blogs/elements/2014/05/insuring-the-apocalypse.html

Coastal flooding ‘may cost $100,000 billion a year by 2100′

The only way is up: A rapid start on cutting emissions is essential
Image: Jan Smith via Wikimedia Commons

by Tim Radford, Climate News Network, February 11, 2014

On the world’s present course, the cost by 2100 of tackling coastal flooding could be beyond the reach of the poorest countries – and ruinously expensive for richer ones.

LONDON – If global warming continues on its present ominous path, and if no significant adaptation measures are launched, then coastal flooding could be costing the planet’s economies $100,000 billion a year by 2100.

And perhaps 5% of the people on the planet – up to 600 million people – could be hit by coastal flooding by the end of the century, according to new research in the Proceedings of the National Academy of Sciences.

Jochen Hinkel from the Global Climate Forum in Berlin and colleagues have compiled, for the first time, global simulation results on future flood damage to buildings and infrastructure on the world’s coastal flood plains.

They expect drastic increases in economic damage because, as sea levels rise with the decades, so will population and investment: there will be more people with more to lose.

Right now, coastal floods and storm surge damage cost the world between $10 billion a year and $40 billion. But as the megacities grow – think of Lagos, or Shanghai, or Manila – more people will be at risk, and, among them, greater than ever numbers of the poorest.

“If we ignore this problem, the consequences will be dramatic,” says Hinkel. “Countries need to take action and invest in coastal protection measures, such as building or raising dykes, amongst other options.”

Provoking a response

And his co-author Robert Nicholls from the University of Southampton warns: “If we ignore sea level rise, flood damages will progressively rise and presently good defences will be degraded and ultimately overwhelmed, hence we must start to adapt now.”

All such projections involve assumptions about the future that cannot be tested, so the authors spread their bets: they considered a range of scenarios involving crude population growth, levels of economic growth with time, and a series of predictions of sea level rise, as icecaps and glaciers melt, and as the oceans warm and expand according to predictable physical laws.

What they could not predict – because such things require political decisions of the kind they hope to provoke with their forecasts – would be the civic and political responses in the next eight decades as storms become more violent and floods more frequent.

Nor did they try to incorporate the natural consequences of human settlement: how much subsidence, for instance, would occur as humans pumped groundwater from aquifers or quarried strata for building material, all things that would lower the levels of the land already at risk from invasion by the sea.

But their predictions, while alarming, are only reinforcements of earlier investigation. In August, a World Bank team calculated that floods would be routinely costing coastal cities $1 trillion a year by 2050.

In July last year, a team from Stanford University in California looked at the challenge of building sea defences and proposed that by far the most efficient solutions would all be natural: dune systems, mangrove forests, reefs, water meadows, kelp forests and natural estuary ecosystems provided the best protection for many people in many circumstances.

And in December scientists from the University of Massachusetts considered the devastation wreaked on New York and other American cities by Superstorm Sandy in October 2012 and warned that such things could happen again and that, once again, natural systems might provide the most efficient  buffers against the buffetings of the weather.

Huge losses

The PNAS authors consider for the purpose of their argument only the increasing costs of either maintaining sea barriers such as dykes or raising them.

By 2100, global average sea level rise could be as low as 25 cm, or as high as 123 cm; between 0.2% and 4.6% of the world’s population could be affected by flooding each year; and losses could be as low as 0.3% or as high as 9.3% of global gross domestic product.

It doesn’t matter very much whether by the end of the century the losses hit the low end of these projections, or the high. They will always be huge. “Damages of this magnitude are very unlikely to be tolerated by society and adaptation will be widespread,” the authors warn.

And there will be tracts of land that no dykes could ever save from the rising waters. The poorest countries are in any case unlikely to be able to meet the costs of sustained protection from the sea.

“If we do not reduce greenhouse gases swiftly and substantially, some regions will have to seriously consider relocating significant numbers of people in the longer run,” says Hinkel. He and his co-authors want to see some significant long-term thinking.

His colleague Professor Nicholls adds: “This long-term perspective is however a challenge to bring about, as coastal development tends to be dominated by short-term interests of, for example, real estate and tourism companies, which prefer to build directly on the waterfront with little thought about the future.” 

http://www.climatenewsnetwork.net/2014/02/coastal-flooding-may-cost-100000-bn-a-year-by-2100/

Worst-case dollar cost of a few feet of rising seas could reach $100 trillion every year, according to the most rigorous scientific study of its kind

by John H. Cushman, Jr., InsideClimate News, February 12, 2014

The world needs to invest tens of billions of dollars a year in beefing up shoreline defenses against rising oceans or it will face mind-boggling costs in the decades to come, according to new research published this week in the Proceedings of the National Academy of Sciences.

If nations don't build up dikes, levees and sea walls, harden existing infrastructure, and preserve natural sponges like wetlands and barrier islands—and if they also do nothing to cut the emissions of greenhouse gases that cause global warming and are driving sea levels higher—the damages could be almost beyond comprehension, the researchers warned.

In a worst case, almost five percent of the world's population could be exposed to flooding at the start of the next century, and the damage could surpass 9% of future global GDP each year.

This future damage from floods, they wrote, "may be one of the most costly aspects of climate change."

Rounded off, this worst-case dollar cost of rising sea levels could reach $100 trillion by the year 2100, they estimated. That's no typo: It's one hundred thousand billions.

Even taking into account the uncertainties in any such work, which the authors recognize, that is a pretty impressive cost to be paid for a few feet of rising seas. And its publication in such a prestigious peer-reviewed journal means it is not to be lightly shrugged off.

They called for a better understanding of the future costs of today's emissions, saying this is "essential for supporting efforts to reduce emissions driving sea-level rise as well as for designing strategies to adapt to increased coastal flood risk."

If their assessment holds up, global average storm surge damages, on a business-as-usual track, would have increased from between roughly $10 and $40 billion per year today to up to $100 trillion a year by the end of century.

The authors, from the Berlin-based think-tank Global Climate Forum and Britain's University of Southampton, said their study described for the first time the findings of a comprehensive global simulation of future flood damages to buildings and infrastructure in coastal flood plains.

Quoted in a press release from the University of Southampton, Jochen Hinkel of GCF, the chief author, said: "If we ignore this problem, the consequences will be dramatic."

He warned that "if we do not reduce greenhouse gases swiftly and substantially, some regions will have to seriously consider relocating significant numbers of people in the longer run."

What's most striking, though, is not the unfathomable figure they cited as their high-end cost. It is that by investing between $10 billion and $70 billion a year, the world could cut back the damages to a mere $80 billion or so a year in the early 22nd century.

Cutting dollar damages from rising seas from $100,000 billion to $80 billion a year would be a hearty return on investment, and well worth the expense, the authors argued.

Robert Nicholls of the University of Southampton, a co-author of the paper, said: "If we ignore sea-level rise, flood damages will progressively rise and presently good defenses will be degraded and ultimately overwhelmed. Hence we must start to adapt now, be that planning higher defenses, flood proofing buildings and strategically planning coastal land use."

"Poor countries and heavily impacted small-island states are not able to make the necessary investments alone, they need international support," he said.

But Nicholls questioned whether nations were capable of acting now to stave off devastation a hundred years from now.

"This long-term perspective is however a challenge to bring about, as coastal development tends to be dominated by short-term interests of, for example, real-estate and tourism companies, which prefer to build directly at the waterfront with little thought about the future," he said.

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http://insideclimatenews.org/content/report-describes-unfathomable-cost-inaction-rising-seas

12 Million Egyptians to be Affected by Climate Change

12 Million Egyptians to be Affected by Climate Change

by Mohamed Abdel Salam, January 2, 2010 


Cairo: A study conducted by the Center for Remote Sensing at Boston University, commissioned by the Arab Forum for Environment and Development, warned that Egypt would be one of the Arab countries most affected by climate change. The study analyzed a variety of scenarios of climate change impact, particularly on coastal areas, based on satellite images of the region, and showed that Egypt would be the most affected Arab country due to a rise in sea levels. The study stated that, “at least 12 million Egyptians will be forced to migrate from their area of residence in parts of the Nile Delta and that with a rise in sea level of 5 meters, almost one third of the total affected Arab population would be Egyptian."

The study was prepared by Dr. Eman Ghoneim, a research professor at the Center for Remote Sensing, and devoted a large portion of its findings to the impact of rising sea levels in the Nile Delta. The study warned, “under the scenarios of rising sea levels, much of the Nile Delta would be lost forever, and the analysis by the remote sensing and geographic information system classified some areas in the Nile Delta at risk if sea levels rise by one meter.” The report estimated that a rise of only one meter could engulf much of the Nile Delta. With about one third of the Delta area underwater, some of its coastal cities, such as Alexandria, Edco, Port Said and Damietta, would be in great danger. Under this scenario, it is estimated that about 8.5% of the country’s population (7 million) would be forced to migrate to other areas.
The study added, “In the extreme case scenario of a 5-meter sea level rise, more than half of the Nile Delta (58%) will face devastating effects and 10 major cities would be threatened, including Alexandria, Damanhur, Kafr El-Sheikh, Damietta, Mansoura and Port Said. Rising water would drown productive plots of agricultural land and force about 14% of the country’s population (11.5 million) to move to areas of the more densely populated areas south of the Nile Delta region.”

The study went on to say that “the Nile Delta, which covers about 24,900 square kilometers, and accounts for about 65% of agricultural land in Egypt, was once the largest site for sediment deposits in the basin of the Mediterranean Sea. It is an extreme example of low, flat land located in an area that is very vulnerable to rising sea levels.” The Delta is threatened due to accelerated erosion of the coastline and the establishment of the Aswan High Dam in 1962, which subsequently sequestered large amounts of sediment behind the dam in Lake Nasser.

The study showed that coastal erosion of the Delta as a result of natural causes and the extraction of groundwater can be seen in satellite images, especially near the coastal cities of Rosetta and Damietta. The analysis of satellite images shows that the Ras Rashid “Rosetta” lost almost 9.5 square kilometers of area. Likewise, the coastline retreated 3 km in the last 30 years (1972-2003), meaning that this part of the Delta declined at the alarming rate of about 100 meters per year.

Study also discussed the consequences of climate change on the Arab region as a whole, including the impact of rising sea levels and its effects on the growth of cities, stating that the southern part of the Nile Delta is now suffering from uncontrolled population growth in the city of Cairo. The results also showed a loss of about 12% (62 square kilometers) of the agricultural areas adjacent to Cairo between 1984 and 2002.

Link:  http://bikyamasr.com/wordpress/?p=7325