Pakistan's coastal villagers retreat as seas gobble land

Rina Saeed Khan in Reuters via the Thomson Reuters Foundation: For fisherman Sammar Dablo, it was as if "the seawater stole our homes" when land erosion forced his village to relocate further inland on Pakistan's south coast.

The people of the fan-shaped Indus Delta, where the Indus River meets the Arabian Sea, are among the poorest of the poor, mostly illiterate and living in wooden shacks on the mud flats. As seawater has washed into the delta, destroying thousands of hectares of fertile land and contaminating underground water channels, they survive by fishing in the saltwater creeks where dolphins are a common sight.

...The move was not easy, as households had to spend 15,000 rupees ($149) each to build new huts for themselves, he added. The story of Phirt village is not an isolated case. According to Dablo, many other communities in the delta are also shifting as their land disappears.

The latest scientific report from the Intergovernmental Panel on Climate Change pointed out that at the same time as sea levels are rising, most Asian deltas are sinking due to groundwater extraction, floodplain engineering and the trapping of sediment by dams.

The Indus Delta has seen an 80 percent reduction in sediment since the early 20th century, according to a 2009 paper published in Nature Geoscience. Around 20 dams and a large number of canals divert the waters of the Indus River, depriving the delta of fresh water.

Some inhabitants have moved to inland mud flats, where they do not have to buy the land they occupy. Others are decamping to Karachi’s coastal villages where relatives have settled. ... Climate change is clearly increasing vulnerabilities in the delta area. Sea-level rise is contributing to higher storm surges, erosion, flooding and salinity, according to WWF-Pakistan...

NASA view of the Indus River delta

In Jakarta, that sinking feeling is all too real

Bill Tarrant at the Thomson Reuters Foundation via Reuters: …"Jakarta is a bowl, and the bowl is sinking," said Fook Chuan Eng, senior water and sanitation specialist with the World Bank, who oversees a $189 million flood mitigation project for the city.

The channels of the Ciliwung and other rivers are sinking. The entire sprawl of Jakarta's north coast - fishing ports, boatyards, markets, warehouses, fish farms, crowded slums and exclusive gated communities - it's all sinking. Even the 40-year-old seawall that is supposed to keep the Java Sea from inundating the Indonesian capital is sinking.

…Flooding from overflowing rivers and canals in the area is at least an annual event that forces Rahmawati and the rest of the kampong to evacuate to public buildings nearby. High-water marks from the last big flood, in 2013, are still visible on the walls of the kampong.

Jakarta is sinking because of a phenomenon called subsidence. This happens when extraction of groundwater causes layers of rock and sediment to slowly pancake on top of each other.

The problem is particularly acute in Jakarta because most of its millions of residents suck water through wells that tap shallow underground aquifers. Wells also provide about a third of the needs of business and industry, according to city data….

Jakarta's skyline, shot by Vian kadal, Wikimedia Commons,  under the Creative Commons Attribution-Share Alike 3.0 Unported license

Dartmouth study finds restoring wetlands can lessen soil sinkage, greenhouse gas emissions

EurekAlert via Darmouth College: Restoring wetlands can help reduce or reverse soil subsidence and reduce greenhouse gas emissions, according to research in California's Sacramento-San Joaquin River Delta by Dartmouth College researchers and their colleagues.

The study, which is one of the first to continually measure the fluctuations of both carbon and methane as they cycle through wetlands, appears in the journal by Global Change Biology.

Worldwide, agricultural drainage of organic soils has resulted in vast soil subsidence and contributed to increased atmospheric carbon dioxide concentrations. The California Delta was drained more than a century ago for agriculture and human settlement and has since experienced subsidence rates that are among the highest in the world. It is recognized that drained agriculture in the Delta is unsustainable in the long-term. To help reverse subsidence and capture carbon, there is interest in restoring drained agricultural land-use types to flooded conditions, but flooding may increase methane emissions. Carbon dioxide is the primary greenhouse gas emitted through human activities, but pound for pound, methane's impact on climate change is more than 20 times greater than carbon dioxide.

Researchers at Dartmouth, UC-Berkeley and UC-Davis installed monitoring equipment on three moveable four-meter towers, measuring carbon dioxide and methane concentrations above a pasture and a cornfield that had been drained and a flooded rice paddy, a newly restored wetland and a wetland that underwent restoration in 1997. They found that the drained sites were net carbon and greenhouse gas sources. Conversely, the restored wetlands were net sinks of atmospheric carbon dioxide, but they were large sources of methane emissions, says co-author Jaclyn Hatala Matthes, an assistant professor an assistant professor in Dartmouth's Department of Geography. "However, we do expect that the methane emissions will stabilize over time," she says. "We've seen that emissions tend to increase for the first few years, and that this increase is correlated with the increase in wetland plant growth and spread during this time."...

A brown swamp, shot by the US Fish and Wildlife Service

The sinking mega-cities

A bulletin from Lloyd's: As sea levels rise, ground levels in coastal megacities are also falling – with potentially disastrous implications for insurers. Insurers of large property portfolios in the world’s great coastal cities will have factored the effects of climate change into their catastrophe models – including rising sea levels and more frequent storm surges. But what’s often missed is that many of these cities are sinking faster than the water is rising. In some, subsidence outstrips sea level rise by a factor of ten to one.

Together with sea water inundation and flood damage, this can have disastrous consequences for the built environment – and property and business interruption insurers. The surge that overwhelmed New Orleans following Hurricane Katrina, and the subsequent cascading collapse of critical infrastructure, offered a glimpse of the sort of scenario underwriters fear. “We’re going down and the sea is coming up,” confirms Gilles Erkens, of the Deltares Research Institute in Utrecht. “Potential losses could run into hundreds of millions of dollars every year.”

The causes are varied. Foremost is large-scale groundwater extraction for drinking water and industrial processes – although elsewhere, like Los Angeles, it is oil and gas extraction that is to blame. Some urban areas are also constructed on multiple layers of soft soil, which compacts when built on – one of the problems facing New Orleans, for instance, and a feature of megacities that spring up on river deltas, such as Guangzhou in south west China.

One of the most severely affected cities was Tokyo, which grew rapidly in the middle of the last century and sunk over four metres as a result – until drastic remedial measures were put in place in the 1970s to restrict the extraction of groundwater. Since then the subsidence has stabilised. But from Jakarta and Dhaka to Venice, the risks are still all too real…

Jakarta is subsiding faster than any other megacity. The northern part has sunk by nearly four metres in the last 35 years, mainly due to groundwater extraction as the population has mushroomed and former agricultural land has been taken over by massive residential and industrial developments.

...Venice sunk about 120mm in the 20th century due to natural and human causes. In addition, the sea level rose about 110mm. A range of measures – such as restrictions on groundwater extraction – were introduced to stabilise the problem. But recent satellite mapping suggests these may not be enough, as the city is still subsiding by one to two millimetres a year. The causes are two-fold....

A waterside shanty in Jakarta, shot by Thehero, Wikimedia Commons, under the Creative Commons 2.0 license

Could Sandy happen again? Maybe, says Tufts geologist

Newswise via Tufts University: Almost a year after Hurricane Sandy, parts of New York and New Jersey are still recovering from billions of dollars in flood damage. Tufts University geologist Andrew Kemp sees the possibility of damage from storms smaller than Sandy in the future.

"Rising sea levels exacerbate flooding," says Kemp. "As sea level rises, smaller and weaker storms will cause flood damage." An assistant professor in Tufts' Department of Earth and Ocean Sciences, Kemp co-authored a study on sea-level change close to New York that was published recently in the Journal of Quaternary Science. http://onlinelibrary.wiley.com/doi/10.1002/jqs.2653/abstract

Sandy hit New York as a team led by Kemp was researching sea-level change and flooding that had occurred in seven historically damaging hurricanes in New York since 1788. Last October, Sandy's storm surge hit the coast at high tide, but storm and tidal conditions were not the only cause of the devastation, Kemp says. Seawaters off New York's coast have risen 16 inches since 1778, the year of New York City's first major recorded storm, his research shows.

To make this determination Kemp and his team studied salt-marsh sediments from Barnegat Bay in northern New Jersey, south of the tide gauge at Battery Park in New York. Using sediment cores, long cylinders drilled into the marsh floor that offer scientists a look back through time, they were able to reconstruct sea-level changes since 1788.

Kemp cites two factors for rising seas. One is the natural sinking of land called glacio-isostatic adjustment. A second factor, and one supported by the latest report from the Intergovernmental Panel on Climate Change (IPCC), points to the melting of the ice-covered terrain of Greenland and Antarctic as well as the thermal expansion of ocean waters.

Looking forward, Kemp sees the possibility of storms less powerful than Sandy inflicting serious damage. He uses a basketball analogy. "It's like playing basketball and raising the level of the court so that shorter and shorter people can dunk. It makes low lying property and infrastructure more vulnerable at a time when developers are pumping money into coastal cities and towns." ...

Flooding in Marblehead, Massachusetts, after Hurricane Sandy, shot by The Birkes, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

Sinking cities in Indonesia caused by groundwater and gas extraction

Rosenstiel School of Marine &Atmospheric Sciences News: Jakarta and several other major Indonesia cities are sinking at alarming rates of up to 22 cm per year, according to a new study by scientists at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science. This rapid land subsidence of major cities, due to extraction of groundwater for industrial use, is likely to put the densely populated coastal regions below sea level in less than two decades.

"Our study shows that some parts of Jakarta, and elsewhere in Indonesia, will be below sea level in less than 20 years if they don't stop pumping groundwater," said Rosenstiel School Professor Falk Amelung, a co-author of the study.

...The researchers attributed this rapid land subsidence to groundwater extraction in four major urban areas, including in the capital and largest city of Jakarta (population: 9.5 million), Bandung (population: 2.4 million), Pekalongan (population: 200,000), and Semarang (population: 1.5 million). Indonesia's municipal water supply serves only 25% of its more than 240 million people therefore the majority of the population and industries rely heavily on groundwater extraction for water. Land subsidence from gas field exploitation was also shown to occur near the Indonesian cities of Lhokseumawe and in the Sidoarjo regency.

Unlike Venice, which is sinking at a rate of 2 to 3 millimeters per year, heavily developed regions of Indonesia, including in Jakarta and five other major cities are sinking at rates of tens of centimeters per year.

..."Since these cities are close to sea level and because the subsidence is extremely rapid, the societal impacts could be huge, both in terms of water resources and sinking of the land relative to the ocean," said Chaussard. "Understanding of the processes involved and continuing the monitoring are thus critical for mitigation purposes."....

An aerial view of north Jakarta, shot by Amelia Guo, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license

OECD study warns of nine-fold increase in losses from flooding of major coastal cities

Frank McDonald in the Irish Times: Vulnerable coastal cities could suffer a nine-fold increase in losses from flooding over the next 40 years due to a combination of climate change, rapid population increases, economic growth and land subsidence, according to a new report.

The report, commissioned by the Organisation for Economic Co-operation and development (OECD), estimates that average global flood losses of €4.5 billion a year in 2005 could rise to €39 billion by 2050 with projected socio-economic change alone.

Future Flood Losses in Major Coastal Cities, published in Nature Climate Change, examines 136 of the world’s largest coastal cities as part of an ongoing OECD project to explore the policy implications of flood risks due to climate change and economic development.

The cities most at risk, as measured by annual average losses due to floods, include Miami, New York, New Orleans, Boston and Tampa-St Petersburg in the US, Guangzhou and Shenzen in China, Mumbai in India, Nagoya and Osaka-Kobe in Japan and Vancouver in Canada.

Due to their high wealth and low protection, three American cities – Miami, New York and New Orleans – account for 31 per cent of the losses across all 136 cities. Adding Guangzhou, the four top cities account for 43 per cent of global losses (as of 2005).

However, if measured in terms of annual losses as a proportion of a city’s wealth, the most vulnerable would be Guangzhou, Guayaquil in Ecuador, Ho Chi Minh City (formerly Saigon) in Vietnam and Abidjan, capital of Côte d’Ivoire (Ivory Coast). Dublin was not included....

The Chelsea Piers in New York City, shot by Marcel René Kalt alias Groovio, Wikimedia Commons,  under the Creative Commons Attribution-Share Alike 2.5 Generic license

Gulf swallowing Galveston faster than thought

Harvey Rice in the San Francisco Chronicle, via the AP and the Houston Chronicle: Rising sea levels are likely to cover the coastal highway on the unprotected west end of Galveston sooner than previously predicted. A 2007 study underwritten by the city of Galveston that anticipated rising sea levels would cover the highway within 60 years appears to have been overly optimistic.

The $50,000 geological hazard report was prepared for the city by geologists from the University of Texas, Rice University and Texas A&M University but then shelved. The report based its calculation on historic sea level rise and failed to include climate change. Sea levels are rising much faster than previous estimates that accounted for climate change, according to reports released in December by U.S. government scientists and in November by the World Bank.

"It's higher than the estimates they gave us five years ago," said Jim Lester, president of the Houston Advanced Research Center, whose scientists are experienced in coastal issues.

Sea-level rise may pose an even graver problem for Galveston than other coastal areas because the island is sinking at a faster rate than most other areas in the country, a condition known as subsidence. "If you assume subsidence will occur, that means sea-level rise will be even worse than in the rest of the country," said Stephen Gill, senior scientist with the National Oceanic and Aeronautics Administration, or NOAA.

Erosion and loss of protective wetlands are further eating away at the island, said Val Marmillion, managing director of America's Wetland Foundation. The island could shrink by one-third within 30 years, said Marmillion, whose organization based its conclusions on a $4.2 million study by Entergy of sea-level rise threats to the Gulf Coast....

Water in the streets of Galveston, around 1915, shot by Rex Dunbar Frazier

Metro Manila is sinking, says expert

Christina Mendez in the Philippine Star:  The entire Metro Manila has started to “sink” due to global warming and floods and to the rampant setting up of illegal fishponds in nearby provinces, an expert from the University of the Philippines’ Marine Institute said yesterday.

Fernando Siringan made the revelation when he faced the Senate committee on climate change. Siringan explained the cause of massive flooding in Metro Manila in recent weeks. “One major point is that the land in Malabon is sinking, and not only in Malabon. Actually, the entire Metro Manila is sinking. And you’ll have to consider that it’s sinking not slowly, it’s sinking at several centimeters per year,” Siringan said.

He also said there is no sense in dredging rivers if it continues to be filled with trash. He said the rising sea level as well as oil subsidence should be considered in the conduct of anti-flood projects, especially in the Caloocan, Malabon, Navotas and Valenzuela (Camanava) area. “There are places in Malabon and Pampanga where soil subsidence is at 10 centimeters and half a meter every year, respectively,” Siringan said.

Sen. Loren Legarda, chairperson of the Senate committee on climate change, echoed Siringan’s statements. “This is not new because we have been saying this even before. Many areas are sinking every year so this should be incorporated in the planning of projects in the affected areas,” Legarda said. In the long term, there is a need to clear up waterways, rivers and lakes, Legarda said.

She said there is also a need to remove human settlements in major drainage systems. “We will collate all of these together so that we will be able to have a framework on how to address the massive flooding in the metropolis,” she said...

A view of Manila in 1992, during a chess olympiad, shot by GFHund, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license

Venice hasn't stopped sinking after all

Terra Daily via SPX: The water flowing through Venice's famous canals laps at buildings a little higher every year - and not only because of a rising sea level. Although previous studies had found that Venice has stabilized, new measurements indicate that the historic city continues to slowly sink, and even to tilt slightly to the east.

"Venice appears to be continuing to subside, at a rate of about 2 millimeters a year," said Yehuda Bock, a research geodesist with Scripps Institution of Oceanography at the University of California, San Diego, in La Jolla, Calif., and the lead author of the new article on the city's downward drift. "It's a small effect, but it's important," he added.

Given that sea level is rising in the Venetian lagoon, also at 2mm per year, the slight subsidence doubles the rate at which the heights of surrounding waters are increasing relative to the elevation of the city, he noted. In the next 20 years, if Venice and its immediate surroundings subsided steadily at the current rate, researchers would expect the land to sink up to 80 mm (3.2 inches) in that period of time, relative to the sea.

Venice's subsidence was recognized as a major issue decades ago, he noted, when scientists realized that pumping groundwater from beneath the city, combined with the ground's compaction from centuries of building, was causing the city to settle. But officials put a stop to the groundwater pumping, and subsequent studies in the 2000s indicated that the subsidence had stopped, he said....

Some flooding in Venice, shot by Xell, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 2.0 Austria license

'Venice of Northwest Alaska' sinking because of climate change

Alex DeMarban in Alaska Dispatch: The permafrost has sunk so much in one Northwest Alaska village that bridges are shifting, outdoor stairways hang over the ground and sagging water pipes are prone to break and freeze. Those are a few of the ways climate change is affecting life in the Inupiat village of Selawik, according to the Alaska Native Tribal Health Consortium's Center for Climate and Health.

"You essentially have the Venice of Northwest Alaska, where the whole community is gradually sinking and people are struggling with how they'll possibly fix all this," said Michael Brubaker, with the Alaska Native Tribal Health Consortium. Brubaker runs the center, which is studying the effects of climate change on facilities and people in Northwest Alaska. The consortium plans to turn its attention next to Bristol Bay villages in Southwest Alaska.

The effects of a changing climate are widespread in Selawik, some 70 miles southeast of Kotzebue. The village has 180 homes and it seems each has suffered one problem or another related to unstable tundra, said Carrie Skin, the city bookkeeper. Windows are cracking. Doors are jamming. Ceilings are breaking loose from joists.

Stand a distance from her house and you'll notice it's not level. One side "lops toward the Selawik River," which is five feet away and coming closer as it erodes, she said. Skin signed up with the tribal housing department to have her house leveled, but that won't happen any time soon. The list for leveling work is long and tribal funds are limited. "You have to be very lucky to be the chosen one," she said.

Selawik isn't alone in its efforts to grapple with climate change. In numerous trips to five Northwest Alaska communities over the last year and a half, Brubaker reports finding warmer temperatures are changing life in the Arctic, and often not for the better...

Selawik Flats, Selawik National Wildlife Refuge, shot by the US Fish and Wildlife Service

Floods show what lies ahead for sinking Bangkok

Amelie Bottollier-Depois in PhysOrg points out a major problem: The Thai capital, built on swampland, is slowly sinking and the floods currently besieging Bangkok could be merely a foretaste of a grim future as climate change makes its impact felt, experts say. The low-lying metropolis lies just 30 kilometres (18 miles) north of the Gulf of Thailand, where various experts forecast sea level will rise by 19 to 29 centimetres (7 to 11 inches) by 2050 as a result of global warming.

Water levels would also increase in Bangkok's main Chao Phraya river, which already overflows regularly. If no action is taken to protect the city, "in 50 years... most of Bangkok will be below sea level," said Anond Snidvongs, a climate change expert at the capital's Chulalongkorn University.

But global warming is not the only threat. The capital's gradual sinking has also been blamed on years of aggressive groundwater extraction to meet the growing needs of the city's factories and its 12 million inhabitants.

As a result Bangkok was sinking by 10 centimetres a year in the late 1970s, according to a study published last year by the World Bank, the Asian Development Bank (ADB) and the Japan Bank for International Cooperation....

Floods in Thailand's Ayutthaya Province in November, 2011, shot by the UN

A hidden risk of climate change: More property damage from drought-induced soil subsidence in Europe

Swiss Re: Europe is witnessing a dramatic increase in property damage as a result of soil subsidence. Climate change could magnify those risks, a new Swiss Re publication shows. A new loss model developed by Swiss Re and the Swiss Federal Institute of Technology (ETH Zurich) suggests that soil subsidence will worsen and spread in Europe, with some areas seeing a more than 50% rise in future losses.

Prolonged dry spells, as recently seen in parts of Europe, can cause the ground to sink by so much that cracks appear in the earth, tearing apart the foundations of houses, bridges, factories and other structures. In the worst case, whole buildings can collapse. Climate change will magnify these risks as factors such as rising average temperatures and more erratic rainfall continue to alter soil conditions.

"As our climate continues to change, the risk of property damage from soil subsidence is not only increasing but also spreading to new regions in Europe," says Matt Weber, Head of Property & Specialty Underwriting at Swiss Re.

European property insurers face major potential losses from droughtinduced soil subsidence, states Swiss Re's latest publication "The hidden risks of climate change: An increase in property damage from drought and soil subsidence in Europe". In France alone, subsidence-related losses have risen by more than 50% in the last two decades, costing affected regions an average of EUR 340 million per year.

...Large parts of Europe will experience more sporadic rainfall and drier soils in the future and these areas will therefore face greater losses from shifting soil, the model shows. In some regions, the soil subsidence loss potential for the period 2021– 2040 is expected to increase by more than 50% compared to today...

From March 2007, a subsiding section of the embankment of the Stubbins to Accrington railway branch line that opened in 1846. Since its closure in 1966 the years of neglect and tree root growth have taken their toll. Today the embankment is near to total collapse. Shot by Paul Anderson, Wikimedia Commons via Geograph UK, under the Creative Commons Attribution-Share Alike 2.0 Generic license

Chesapeake region leads in sea level rise

Sabri Ben-Achour in WAMU.org: Communities across the globe are beginning to come to grips with climate change and sea level rise. One of the places where the water is rising especially quickly is right here in the Chesapeake Bay region. The Chesapeake Bay has areas which are experiencing among the highest rates of sea-level rise on the East Coast. This is because the ground in many areas is sinking.

Towns are starting to see the effects and they're bracing for it. But there's more than just climate change behind the rising tide. The beach in Ocean City is a major tourist draw, it stretches hundreds of feet from the board walk, with giant dunes studded with grasses a little farther south. This beach would probably not be here right now if it weren't for the fact that tons of sand are brought in every few years to replenish it, especially after major storms.

"Beach replenishment serves as storm protection for the town of Ocean City. It's the equivalent of the levees in New Orleans for us," says Terry McGean, the Ocean City beach engineer. "They dredge sand from a couple miles offshore, and we pump that material onto the beach and basically bring the beach back."

Storms and erosion aren't new, but there's something else going on here, that's making every storm a little more serious: Tidal gauges here have measured an increase in sea level. It's gone up seven inches over 30 years -- that's 5.5 millimeters per year, and almost two feet per century.

Dr. John Boon, a professor emeritus with the Virginia Institute of Marine Science, says the sea level is rising throughout this region, and some parts have it particularly bad. "We have relative sea-level rise rates that are the highest on the U.S. East Coast," he says…

Ocean City, Maryland, in a US Army Corps of Engineers photo