solarix wrote: »
One common misconception of climate change is that it will be only in one direction. Even though the average temperature is rising (putting more energy into the weather), it will cause weather events to be more extreme in both directions, with droughts, tornadoes and hurricanes, as well as blizzards and slowing of the gulf stream. Of course, until something unprecidented happens like New Orleans flooding, you won't be convinced.
Geophysical Research Abstracts
Vol. 16, EGU2014-14606, 2014
EGU General Assembly 2014
© Author(s) 2014. CC Attribution 3.0 License.
Sinking coastal cities
Gilles Erkens (1,2), Tom Bucx (1), Rien Dam (1), Ger De Lange (1), and John Lambert (1)
(1) Deltares Research Institute, Utrecht, The Netherlands, (2) Faculty of Geosciences, Utrecht University, Physical Geography,
Utrecht, The Netherlands ([email protected])
In many coastal and delta cities land subsidence now exceeds absolute sea level rise up to a factor of ten. Without
action, parts of Jakarta, Ho Chi Minh City, Bangkok and numerous other coastal cities will sink below sea level. Land subsidence increases flood vulnerability (frequency, inundation depth and duration of floods), with floods causing major economic damage and loss of lives. In addition, differential land movement causes significant economic losses in the form of structural damage and high maintenance costs. This effects roads and transportation networks, hydraulic infrastructure – such as river embankments, sluice gates, flood barriers and pumping stations, sewage systems, buildings and foundations. The total damage worldwide is estimated at billions of dollars annually.
Excessive groundwater extraction after rapid urbanization and population growth is the main cause of severe land
subsidence. In addition, coastal cities are often faced with larger natural subsidence, as they are built on thick
sequences of soft soil.
Because of ongoing urbanization and population growth in delta areas, in particular in coastal megacities, there is,
and will be, more economic development in subsidence-prone areas. The impacts of subsidence are further exacer-
bated by extreme weather events (short term) and rising sea levels (long term).Consequently, detrimental impacts
will increase in the near future, making it necessary to address subsidence related problems now.
Subsidence is an issue that involves many policy fields, complex technical aspects and governance embedment.
There is a need for an integrated approach in order to manage subsidence and to develop appropriate strategies
and measures that are effective and efficient on both the short and long term. Urban (ground)water management,
adaptive flood risk management and related spatial planning strategies are just examples of the options available.
A major rethink is needed to deal with the ‘hidden’ but urgent threat of subsidence.
As subsidence is spatially different and can be caused by multi processes, an assessment of subsidence in delta
cities needs to answer questions such as: what are the main causes, how much is the current subsidence rate and
what are future scenarios (and interaction with other major environmental issues), where are the vulnerable areas,
what are the impacts and risks, how can adverse impacts can be mitigated or compensated for, and who is involved
and responsible to act?
In this study a quick-assessment of subsidence is performed on the following mega-cities: Jakarta, Ho Chi Minh
City, Dhaka, New Orleans and Bangkok. Results of these case studies will be presented and compared, and a
(generic) approach how to deal with subsidence in current and future subsidence-prone areas is provided.
San Francisco Bay's History Like most estuaries, San Francisco Bay is a very young feature, geologically speaking. Twenty thousand years ago there was no bay. At that time the world was in the grip of the last ice age, and much of the planet's water was frozen into glaciers that covered a large part of the northern continents. With less water to fill the oceans, sea level was nearly 150 meters (over 400 feet) lower and the Pacific coastline was 30 km (20 miles) west of where it lies today. Imagine having to travel all the way to the Farallon Islands to go walking on the beach or surfing in the ocean! The Bay itself was dry land, with rivers running through the low-land areas on their route to the sea.
As the glaciers melted over centuries, the ocean waters rose and the shoreline crept back eastward, toward land. By 10,000 years ago the ocean had spread inland through a gap in the outer Coast Ranges that we know today as the Golden Gate (Figure 1), and seawater began to fill the Bay. For thousands of years, sea level rose rapidly at nearly 2.5 cm (one inch) per year, advancing the shoreline progressively inland. Several thousand years ago, the rate of rise slowed and sediments began to accumulate in the shallows faster than the sea could cover them. These sediments supported the expansion of tidal mudflats and marshes along the Bay's shores, whose vast extent was recorded in the last century, before modern civilization began to reshape the Estuary. We will look at the effects of human modifications on the Estuary in subsequent parts of this exercise.
Global warming could affect storm formation by decreasing the temperature difference between the poles and the equator. That temperature difference fuels the mid-latitude storms affect the Earth’s most populated regions. Warmer temperatures could increase the amount of water vapor that enters the atmosphere. The result is a hotter, more humid environment. At the equator, where conditions are already hot and humid, the change isn’t expected to be large. At the poles, however, the air is cold and dry; a little extra heat and water vapor could raise temperatures greatly. As a result, global warming may cause the temperature difference between the poles and the equator to decrease. and as the difference decreases, so should the number of storms, says George Tselioudis, a research scientist at NASA Goddard Institute for Space Studies (GISS) and Columbia University.
Bad Science: It turns out that a 200-year-old publication for farmers beats climate-change scientists in predicting this year's harsh winter as the lowly caterpillar beats supercomputers that can't even predict the past.
Last fall, the National Oceanic and Atmospheric Administration's Climate Prediction Center (CPC) predicted above-normal temperatures from November through January across much of the continental U.S. The Farmers' Almanac, first published in 1818, predicted a bitterly cold, snowy winter.
The Maine-based Farmers' Almanac's still-secret methodology includes variables such as planetary positions, sunspots, lunar cycles and tidal action. It claims an 80% accuracy rate, surely better than those who obsess over fossil fuels and CO2.
Terms such as "managed retreat" and "beach nourishment" became talking points last Wednesday at a workshop attended by Pacificans and residents of neighboring communities who came out to express their opinions about how to manage erosion problems on the coast.A study organized by the Estuary Partnership in conjunction with the Association of Bay Area Governments is being done to see how coastal erosion can be controlled. Pacifica is part of the so-called San Francisco Littoral Cell study, which focuses on the stretch of coast from here all the way up to San Francisco.
The idea is to plan for sediment management over the next 50 years, taking into account current conditions as well as projected sea level rise and extraordinary events such as a 100-year storm.
Bob Battalio, principal engineer on the study, examined Pacifica's problem spots, including the seawall at Sharp Park that abuts the golf course. He explained how, in years past, that section of Sharp Park beach was wider before the seawall was constructed.
"Are we going to armor our shores and lose beaches?" he asked, showing a cartoon drawing of a sad child forced to walk on rocks instead of sand.
When the Federal Emergency Management Agency issued its new Flood Insurance Rate Map, she and thousands of homeowners in the northwest corner of San Mateo and next to the San Francisco Bay were identified as susceptible to a 100-year flood. The 100-year flood is a FEMA standard for areas where there is a 1 percent chance of a major flood every year. No one can recall any major flooding in the area and the designation more than a decade ago shocked the city and those in the new flood zone. Getting nearly 10,000 residences off the flood map has cost millions through expensive public works projects. Now the city is setting its sights on the last affected area — North Shoreview and portions of North Central San Mateo. In the meantime, Newton and other homeowners with federally backed mortgages contend with costly flood insurance rates that can range from a few hundred to thousands of dollars a year.
“We were all pretty much in shock,” Newton said. “I don’t understand why they’re focusing on floods only when every area in this country is subject to some kind of natural disaster. And I think we, in our area, are probably prone to more earthquakes than floods. I don’t know why every homeowner in the country doesn’t have to pay something for tornadoes, hurricanes, floods; there’s just so many disasters that do, and can happen.”
She bought insurance prior to the map’s release and was grandfathered in at about $300 a year. But her rates have increased over the years; she paid $1,200 last year and expects it to increase again, Newton said.
For those who bought their homes in recent years, many were unexpectedly hit with estimates nearing $10,000 per year.
Her story is one of many in the area who are considered at risk and required to carry flood protection and reduce the burden of claims paid through the agency’s National Flood Insurance Program, according to FEMA officials.
It is a lengthy and costly process that will involve city infrastructure improvements at two pump stations and along the Coyote Point Bayfront levees, estimated to cost $22.35 million in 2009 and 2010, said Susanna Chan, deputy director of the San Mateo Public Works Department.
...Anna Solorzano lives on the 800 block of North Idaho Street in the North Central neighborhood. While closing escrow in 2012, Solorzano said she learned her future included rising flood insurance payments. Her shock didn’t end there, this year she paid $1,000 for an elevation certificate and the news it brought was infuriating — her property was in the flood zone by mere inches, Solorzano said.
“I questioned it over and over again … but I was at the mercy really of FEMA and I still am. It’s whatever they designate, it’s whatever they determine,” Solorzano said. “It’s been nerve-racking because you don’t know what you’re dealing with and as you start to go through these layers and still keep hitting walls, you come to the conclusion it’s a bigger monster; it’s out of your control.”
FEMA rates inevitably increase. Although her first annual payment was $2,500, she shopped around in 2013 and found a cheaper $1,800 annual plan. But this year’s annual quotes jumped to $4,600 to $7,200 to $9,600 before her lender found a $2,800 plan, Solorzano said.
...“Our (insurance) bill was unbelievable. We were speaking to multiple insurance agencies and quotes were coming in for total coverage, which was around $10,000 a year. Isn’t that crazy? It was far beyond anything we anticipated when we bought this (house) and there was no disclosure at all,” Dave Jordan said. “Had we known that ... initial challenge would have been something we’d have to face, I’m pretty sure we wouldn’t have purchased this house.”
This year, they paid $2,300 for the cottage and $4,500 for the main house. The latter amount would have been $1,000 higher but the provider made a mistake and decided to give them the lower rate, Dana Jordan said....
BB. wrote: »
Things change--People will have to adjust to the changes.
niel wrote: »
i have my doubts about the salinity changing that much in a negative way. yes, the glaciers are putting more fresh water into the oceans, but we at the same time are putting more salt into the oceans by tapping the salt from old seas buried underground and have been doing so for many decades at least. all norther cities throw salt onto road surfaces and the culmination of all of that salt goes to the oceans and the gulf of mexico sooner or later and that's just the input from the u s as other nations elsewhere probably do this at times to varying degrees too. eventually it circulates to all reaches of the worlds oceans and seas. how do we know we haven't made the oceans more saline that could be eating away at some of the sea bound ice? the world is a complex thing with many variables with mankind's input to it as having the biggest and most numerous variables.
pleppik wrote: »
The mass of the Earth's oceans is about 275 times the mass of the atmosphere, and global CO2 production is about 150 times global salt production.
That suggests that human activity is changing the salinity of the oceans only 0.002% as fast as we are changing the CO2 concentration in the atmosphere. Or, put another way, it would take about 40,000 years (of current activity levels) to change the ocean salinity by the same amount we change the CO2 levels every year. Even that probably overstates the case, since a large fraction of salt production comes from evaporating ocean water.
Cariboocoot wrote: »
And does that factor in melting the ice caps?
BB. wrote: »
Lets not go down the thread into A.H. and such. There are a lot of bad people out there (past, present, and I am sure, future).