Subida do Nível da Água do Mar

Tópico em 'Climatologia' iniciado por Santos 25 Fev 2007 às 10:45.

  1. Santos

    Santos
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    Nimbostratus

    Registo:
    27 Jan 2006
    Mensagens:
    1,110
    Local:
    -------
    A 12-bedroom guesthouse with beautiful views of the North Sea, a lighthouse and sandy beaches, sounds like prime real estate. But Cliff House is nearly worthless. The offshore wooden barrier that once protected the sand and clay cliffs of this stretch of eastern English coast has broken apart, and the government has decided that with the expected rise in sea levels and storm surges that experts attribute to global warming, some vulnerable coastal areas are no longer worth defending. "The next big storm could take us away," said Diana Wrightson, one of two elderly women who bought Cliff House 26 years ago, assuming the coastline would always be protected. Predictions of rising sea levels usually envision the low-lying islands of the south seas, or cyclone-prone Bangladesh, as the most vulnerable victims. But Britain is part of a growing club of rich countries whose coastal populations feel threatened. Hurricane Katrina looked to many like the shape of things to come when it devastated New Orleans in 2005. Venice is building up its defenses. Holland is rethinking its famous seawalls.

    The fears have grown more acute following the release this month of a report by scientists from 113 countries forecasting temperature rises of 2 to 11.5 degrees Fahrenheit and sea-level rises of 7 to 23 inches by the end of the century. It says global warming is almost certainly man-made. Ronan Uhel, a top official at the European Environment Agency in Copenhagen, said the situation in Happisburgh shows that governments and insurance companies have finally started letting the public know that it will have to do more than buy fuel-efficient cars and better light bulbs to fight global warming. He said citizens can't keep building homes on islands and near lowlands and coastlines, especially in vulnerable areas where it no longer makes sense to rebuild offshore barriers.

    n countries such as Britain, "a national debate is just starting about what is an appropriate policy of adaptation to climate change," Uhel said in an interview. "People are just beginning to realize the risks of global warming and the big lifestyle changes that may be needed to brace for them." Late last year, a new law took effect in England and Wales whereby the government decides whether it makes sense, economically and environmentally, to rebuild barriers. For Happisburgh, 135 miles northeast of London, the answer was no. "Basically, whatever we do to reduce greenhouse emissions, we're going to face about one meter [3.3 feet] sea-level rise on the east coast of England in the next 100 years," Clive Bates, a top official at the British government's Environment Agency, said. "Either we won't be able to defend part of the coast, or it will be too expensive to do it. One of the most troubling issues for us is to decide where we can no longer sustain coastal defense, where we basically need to warn people to retreat." Happisburgh, on the East Anglia coast, has always been vulnerable. Accounts of houses, lighthouses or farmland collapsing into the sea date back to the early 19th century. "But the rate of erosion there now is phenomenal, in excess of 10 meters [33 feet] a year, because of sea-level rise, the collapse of its offshore barrier and the fact that southeastern England is sinking," said Dr. David Viner, a senior scientist at the Climatic Research Unit at the University of East Anglia.

    Britain is already taking steps such as strengthening a barrier that prevents the River Thames from flooding landmarks such as the Houses of Parliament. Meanwhile, Venice is sinking while the Adriatic Sea is rising, sometimes flooding St. Mark's Square, the most visited spot in the fabled city. In 2003 authorities approved a $5.5 billion project dubbed Moses, after the biblical figure who parted the Red Sea, to plant hinged barriers in the seabed just off Venice. The barriers can be raised when tides get too high. Low-lying Holland has waged a battle against the ocean for centuries, building a massive network of dikes and pumps. After a devastating 1953 flood killed 1,835 people, it launched the Delta Project, consisting of storm-surge barriers, giant sluices and dams. Now, just as the project has reached completion, fear of climate change has shifted the theory of disaster control away from blocking floodwaters to managing them. It involves breaching the dikes at key pressure points to ease the destructive force and allow the water to flood unpopulated area
     
  2. Seringador

    Seringador
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    Cumulonimbus

    Registo:
    29 Ago 2005
    Mensagens:
    2,984
    Local:
    Canelas - Vila Nova de Gaia
    Boas,

    De facto o nível do mar tem vindo a subir ligeiramente e numa escala temporal mais alargada.
    Contudo actualemnte existe uma anomalia significativa do nível do mar no Atlântico Este.
    [​IMG]

    No que se refere aos últimos anos,a subida parece indicar uma súbida geral mas...
    http://www.jason.oceanobs.com/html/actualites/applis/niveau_moyen_uk.html

    E reparem o valores de emissões de NO2 - Dióxido Nitrogénio a CHINA está a emitir mais do que os USA e a Europa juntos.
    http://www.esa.int/esaEO/SEMBZNBE8YE_planet_1.html
     
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  3. dj_alex

    dj_alex
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    Nimbostratus

    Registo:
    14 Dez 2005
    Mensagens:
    1,913
    Local:
    Lisboa
    O mapa é meio estranho...pq nas regiões dos Alpes na Europa tem uma poluição enorme... Não entendo muito bem a causa...
     
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  4. mesq

    mesq
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    Cirrus

    Registo:
    28 Jan 2007
    Mensagens:
    24
    Local:
    Porto
    Eu diria que é antes a região de Milão-Turim-Bolonha, de facto uma das mais industrializadas da Europa. ;)

    O que eu não compreendo é aquela mancha em Moçambique. :huh:
     
  5. Seringador

    Seringador
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    Cumulonimbus

    Registo:
    29 Ago 2005
    Mensagens:
    2,984
    Local:
    Canelas - Vila Nova de Gaia
    Não é Moçambique mas África do Sul, mais precisamente a área mais urbanizada e industrializada, onde a exploração mineira (sobretudo as do ouro e diamantes) imperam;)
     
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  6. mesq

    mesq
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    Cirrus

    Registo:
    28 Jan 2007
    Mensagens:
    24
    Local:
    Porto
    Bem visto :thumbsup:
     

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