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EcoTópico!  

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EcoTópico!

Mensagempor DoctorDre » domingo Oct 12, 2008 12:10 pm

Podemos discutir todos os assuntos sobre ecologia, energias renovaveis, protecção do ambiente...
:drink:
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Re: EcoTópico!

Mensagempor DoctorDre » domingo Oct 12, 2008 12:18 pm



:bravo:
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Re: EcoTópico!

Mensagempor Mr Strangelet » domingo Oct 12, 2008 2:23 pm

Vi ontem este carro no TV Turbo!
Este é o primeiro carro totalmente electrico com um design verdadeiramente apaixonante :shock: Em 2011 gostava de ter € para comprar um :D
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Re: EcoTópico!

Mensagempor DoctorDre » domingo Oct 12, 2008 2:39 pm

Mr Strangelet Escreveu:Vi ontem este carro no TV Turbo!
Este é o primeiro carro totalmente electrico com um design verdadeiramente apaixonante :shock: Em 2011 gostava de ter € para comprar um :D


30000€ ou 20000£ ;)

Não é nada caro segundo se antecipa!
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Ambiente - Discussão Geral

Mensagempor DoctorDre » segunda Oct 13, 2008 12:25 am

Foi coincidencia ter criado dois tópicos tão semelhantes em assunto, este e o EcoTópico mas a verdade é que acabei há pouco de ver aquele filme "Uma Verdade Inconveniente" e claro que fiquei em pulgas sobre saber mais sobre o assunto!
Não sei se já viram o filme, mas bem, tirando as picadas politicas a Bush que bem as merece, Al Gore apresenta-se com uma serie de dados cientificos alucinantes e alarmantes e uma serie de factos assustadores sobre o aquecimento global!

Por exemplo, o que pessoalmente mais me alarmou foi, logo no inicio, quando ele fala da relação CO2atm e Tª e mostra os valores em grafico do CO2 nos ultimos 650000 anos e no fim, depois de relacionar esses valores à temperatura (movem-se "juntos" ou paralelamente) junta ao gráfico os ultimos anos e as previsões dos próximos... simplesmente assustador! E só mostrou os valores de CO2... a Tª acompanha...

Outro tema que me chamou atenção e captou curiosidade foi o efeito sobre a corrente do golfo! Não só porque nos afecta em grande mas tb porque se se lembram há pouco saiu o filme "Dia depois de amanha" em que o mundo passava repentinamente do absurdo calor de agora para mais uma era glaciar! Hollywoodismos à parte há um fundamento cientifico, e umas hipoteses de acontecimentos futuros que o comprovam. (Coloco no post seguinte um artigo do "The Guardian" sobre o tema).

Pessoalmente sou uma pessoa com bastante consciencia "verde"... reciclo, alias toda a minha familia recicla. Usamos sempre baterias recarregaveis. Raramente usamos aquecimento no inverno. Damos sempre prioridade a viagens de transportes publicos especialmente para longas viagens, e entre eles o Comboio que suponho ser o mais ecologico. Estou numa fase de transição onde optei pelo uso de bicicleta para trajectos citadinos. Um sem-fim de acções que faço regularmente e que acho que é importante... temos de levar a serio a velha máxima do "Act locally think globally".

Neste tópico espero colocar tudo aquilo que encontrar sobre a situação do ambiente, dados sobre o aquecimento global. As acções para o contrariar ets...

PS: Vejam o filme! Porque eu aconselho, porque o senhor Al Gore me pediu para vos dizer, porque voces devem.

Talvez assim saibam porque nem tudo é drama... já conseguimos reverter um problema ambiental que aqui há 10-15anos estava na ordem do dia... e foi graças à concertação mundial sobre o tema!
Não ajuda à situação actual mas pelo menos já é um sinal que é possivel mudar!
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Re: Tópico do Ambiente!

Mensagempor DoctorDre » segunda Oct 13, 2008 12:27 am

Will global warming trigger a new ice age?
If climate change disrupts ocean currents, things could get very chilly round here, reports Bill McGuire


Bill McGuire
The Guardian, Thursday November 13 2003
Article history


If you can remember back to the bitter winters of the late 1970s and early 80s you might also recall that there was much discussion in scientific circles at the time about whether or not the freezing winter conditions were a portent of a new ice age.

Over the past couple of decades such warnings have been drowned out by the great global warming debate and by consideration of how society might cope in future with a sweltering planet rather than an icebound one. Seemingly, the fact that we are still within an interglacial period, during which the ice has largely retreated to its polar fastnesses, has been forgotten - and replaced with the commonly-held view that one good thing you can say about global warming is that it will at least stave off the return of the glaciers.

Is this really true, or could the rapidly accelerating warming that we are experiencing actually hasten the onset of a new ice age? A growing body of evidence suggests that, at least for the UK and western Europe, there is a serious risk of this happening - and soon.

The problem lies with the ocean current known as the Gulf Stream, which bathes the UK and north-west Europe in warm water carried northwards from the Caribbean. It is the Gulf Stream, and associated currents, that allow strawberries to thrive along the Norwegian coast, while at comparable latitudes in Greenland glaciers wind their way right down to sea level. The same currents permit palms to flourish in Cornwall and the Hebrides, whereas across the ocean in Labrador, even temperate vegetation struggles to survive. Without the Gulf Stream, temperatures in the UK and north-west Europe would be five degrees centigrade or so cooler, with bitter winters at least as fierce as those of the so-called Little Ice Age in the 17th to 19th centuries.

The Gulf Stream is part of a more complex system of currents known by a number of different names, of which the rather cumbersome North Atlantic Meridional Overturning Circulation (Namoc) is probably the most apt. This incorporates not only the Gulf Stream but also the cold return currents that convey water southwards again. As it approaches the Arctic, the Gulf Stream loses heat and part of it heads back to warmer climes along the coast of Greenland and eastern Canada in the form of the cold, iceberg-laden current responsible for the loss of the Titanic. Much, however, overturns - cooling and sinking beneath the Nordic seas between Norway and Greenland, before heading south again deep below the surface.

In the past, the slowing of the Gulf Stream has been intimately linked with dramatic regional cooling. Just 10,000 years ago, during a climatic cold snap known as the Younger Dryas, the current was severely weakened, causing northern European temperatures to fall by as much as 10 degrees. Ten thousand years before that, at the height of the last ice age, when most of the UK was reduced to a frozen wasteland, the Gulf Stream had just two-thirds of the strength it has now.

What's worrying is that for some years now, global climate models have been predicting a future weakening of the Gulf Stream as a consequence of global warming. Such models visualise the disruption of the Namoc, including the Gulf Stream, as a result of large-scale melting of Arctic ice and the consequent pouring of huge volumes of fresh water into the North Atlantic, in a century or two. New data suggest, however, that we may not have to wait centuries, and in fact the whole process may be happening already.

So that the warm, saline surface waters of the Gulf Stream can continue to push northwards, there must be a comparable, deep return current of cold, dense water from the Nordic seas. Disturbingly, this return current seems to have been slowing since the middle of the last century. Bogi Hansen at the Faroese fisheries laboratory, and colleagues in Scotland and Norway, have been monitoring the deep outflow of cold water from the Nordic seas as it passes over the submarine Greenland-Scotland ridge that straddles the North Atlantic at this point. Their results show that the outflow has fallen by 20% since 1950, which suggests a comparable reduced inflow from the Gulf Stream.

Although there is as yet no direct substantiation of this, and his colleagues point to reports of the cooling and freshening of the Norwegian Sea and to temperatures that are already falling in parts of the region as possible evidence of contemporary Gulf Stream weakening.

It also seems that it is not only the intensity of the outflow of cold water that is changing. Bob Dickson of the Centre for Environment, Fisheries, and Aquaculture Science at Lowestoft, and colleagues, have reported a sustained and widespread freshening of returning deep waters south of the Greenland-Scotland ridge, which appears to have been going on for the past three or four decades.

Already the freshening is extending along the North American eastern seaboard towards the equator, in the so-called Deep Western Boundary current.

One of the scariest aspects of the current dramatic changes occurring in the system of North Atlantic currents is that the deep, southward-flowing limb of the Namoc can be thought of as representing the headwaters of the worldwide system of ocean currents known as the Global Thermohaline Circulation. The possibility exists, therefore, that a disruption of the Atlantic currents might have implications far beyond a colder UK and north-west Europe, perhaps bringing dramatic climatic changes to the entire planet.

Yet again, this highlights the fact that global warming, for which we have only ourselves to thank, is nothing more nor less than a great planetary experiment, many of the outcomes of which we cannot predict. Wallace Broecker, an ocean circulation researcher at New York's Lamont-Doherty Earth observatory, described the situation perfectly when he pointed out that "climate is an angry beast and we are poking at it with sticks". Let's hope that when it truly turns on us, its teeth don't match its outrage.

· Bill McGuire is Benfield Professor of Geophysical Hazards and director of the Benfield Hazard Research Centre at University College London. He will appear on BBC2 Horizon's The Big Chill tonight


Guardian.co.uk
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Re: Tópico do Ambiente!

Mensagempor DoctorDre » segunda Oct 13, 2008 12:45 am

Sobre o mesmo tema, mais moderado, o mesmo jornal!

Alarm over dramatic weakening of Gulf Stream
Interactive guide to the Gulf Stream

Ian Sample, science correspondent
The Guardian, Thursday December 1 2005
Article history


The powerful ocean current that bathes Britain and northern Europe in warm waters from the tropics has weakened dramatically in recent years, a consequence of global warming that could trigger more severe winters and cooler summers across the region, scientists warn today.

Researchers on a scientific expedition in the Atlantic Ocean measured the strength of the current between Africa and the east coast of America and found that the circulation has slowed by 30% since a previous expedition 12 years ago.

The current, which drives the Gulf Stream, delivers the equivalent of 1m power stations-worth of energy to northern Europe, propping up temperatures by 10C in some regions. The researchers found that the circulation has weakened by 6m tonnes of water a second. Previous expeditions to check the current flow in 1957, 1981 and 1992 found only minor changes in its strength, although a slowing was picked up in a further expedition in 1998. The decline prompted the scientists to set up a £4.8m network of moored instruments in the Atlantic to monitor changes in the current continuously.

The network should also answer the pressing question of whether the significant weakening of the current is a short-term variation, or part of a more devastating long-term slowing of the flow.

If the current remains as weak as it is, temperatures in Britain are likely to drop by an average of 1C in the next decade, according to Harry Bryden at the National Oceanography Centre in Southampton who led the study. "Models show that if it shuts down completely, 20 years later, the temperature is 4C to 6C degrees cooler over the UK and north-western Europe," Dr Bryden said.

Although climate records suggest that the current has ground to a halt in the distant past, the prospect of it shutting down entirely within the century are extremely low, according to climate modellers.

The current is essentially a huge oceanic conveyor belt that transports heat from equatorial regions towards the Arctic circle. Warm surface water coming up from the tropics gives off heat as it moves north until eventually, it cools so much in northern waters that it sinks and circulates back to the south. There it warms again, rises and heads back north. The constant sinking in the north and rising in the south drives the conveyor.

Global warming weakens the circulation because increased meltwater from Greenland and the Arctic icesheets along with greater river run-off from Russia pour into the northern Atlantic and make it less saline which in turn makes it harder for the cooler water to sink, in effect slowing down the engine that drives the current.

The researchers measured the strength of the current at a latitude of 25 degrees N and found that the volume of cold, deep water returning south had dropped by 30%. At the same time, they measured a 30% increase in the amount of surface water peeling off early from the main northward current, suggesting far less was continuing up to Britain and the rest of Europe. The report appears in the journal Nature today.

Disruption of the conveyor-belt current was the basis of the film The Day After Tomorrow, which depicted a world thrown into chaos by a sudden and dramatic drop in temperatures. That scenario was dismissed by researchers as fantasy, because climate models suggest that the current is unlikely to slow so suddenly.

Marec Srokosz of the National Oceanographic Centre said: "The most realistic part of the film is where the climatologists are talking to the politicians and the politicians are saying 'we can't do anything about it'."

Chris West, director of the UK climate impacts programme at Oxford University's centre for the environment, said: "The only way computer models have managed to simulate an entire shutdown of the current is to magic into existence millions of tonnes of fresh water and dump it in the Atlantic. It's not clear where that water could ever come from, even taking into account increased Greenland melting."

Uncertainties in climate change models mean that the overall impact on Britain of a slowing down in the current are hard to pin down. "We know that if the current slows down, it will lead to a drop in temperatures in Britain and northern Europe of a few degrees, but the effect isn't even over the seasons. Most of the cooling would be in the winter, so the biggest impact would be much colder winters," said Tim Osborn, of the University of East Anglia climatic research unit.

The final impact of any cooling effect will depend on whether it outweighs the global warming that, paradoxically, is driving it. According to climate modellers, the drop in temperature caused by a slowing of the Atlantic current will, in the long term, be swamped by a more general warming of the atmosphere.

"If this was happening in the absence of generally increasing temperatures, I would be concerned," said Dr Smith. Any cooling driven by a weakening of the Atlantic current would probably only slow warming rather than cancel it out all together. Even if a slowdown in the current put the brakes on warming over Britain and parts of Europe, the impact would be felt more extremely elsewhere, he said.


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Re: Tópico do Ambiente!

Mensagempor DoctorDre » segunda Oct 13, 2008 1:00 am

A Current Controversy: Is Europe About To Freeze?
ScienceDaily (Feb. 22, 2002)

...

This process, called thermohaline circulation, only happens in two regions of the Earth's polar areas. But it is responsible for much ocean circulation, including the critical currents that help keep parts of North America and Europe far warmer than they would otherwise be, considering the far north latitudes at which they lie – most of Great Britain is at the same latitude as central Canada.

This circulation process, researchers say, is not inevitable. Research suggests it may have fluctuated or even stopped numerous times in Earth's distant past, and that it's especially sensitive to moderate increases in temperature or influxes of fresh water. The same very cold, very salty water that sinks in the far North Atlantic Ocean simply won't sink if it's just a little bit warmer or a little bit less salty. And at various times, it appears these changes have happened not in geologic terms of thousands of years, but rather decades.
"This system does not respond in what we call a linear manner," Clark said. "Once you start putting on the brakes, this circulation pattern could slow down faster and faster and eventually stop altogether."
Research has found that some of the Earth's most rapid climatic shifts – up to 15 degrees in decades or less – have in the past occurred during glacial periods, when large ice sheets advanced from the polar regions as far south as New York City, among other places. Some scientists have even theorized that the wild temperature fluctuations of the last ice age may have retarded the evolution and development of humans as a species, as they struggled to cope with rapidly changing conditions.
We are now in an "interglacial" period that, in theory, may have less volatility, but could also be coming to an end.
Global warming will simply delay the inevitable, Clark said, because it actually should be about time for Earth to enter its next ice age. There's a fairly well defined pattern of about 10,000-year-long interglacial periods followed by 90,000-year-long ice ages, and the current interglacial period is already more than 10,000 years old.
"At this point we just aren't sure what to expect in terms of climatic volatility," Clark said. "But the more we learn about them, it becomes clear that these thermohaline circulation patterns are quite sensitive to temperature and influxes of fresh water, such as you might get with changing precipitation patterns triggered by global warming, not to mention melting ice caps or glaciers."
So the paradox, the scientists say, is that the same greenhouse effect which might make the Earth warmer, overall, could have the opposite effect on much of Europe by slowing or shutting down the warm ocean circulation patterns on which it depends.
"Most, but not all, coupled general circulation model projections of the 21st century climate show a reduction in the strength of the Atlantic overturning circulation with increasing concentrations of greenhouse gases," the researchers said in their report in Nature. "If the warming is strong enough and sustained long enough, a complete collapse cannot be excluded." This prospect – the collapse of the thermohaline circulation patterns that dictate its climate - has raised enough concern, Clark said, that Great Britain recently launched a $40 million research program to analyze this phenomena and its possible implications. And the National Academy of Sciences recently issued a report that made reference to an "inevitable surprise" of "climate changes with startling speed."
At this time, Clark said, some of the best potential to improve the ocean and atmospheric computer models that could help resolve some of these questions about future climate lie in studies of the distant past. Ice cores from Greenland glaciers have been instrumental in this work, he said, providing a look backwards at climatic conditions more than 100,000 years into the past, and work in that area will continue.


ScienceDaily
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Re: Tópico do Ambiente!

Mensagempor jonhdoe » segunda Oct 13, 2008 9:23 am

Eu vi esse filme/documentário e achei fenomenal, acredito também que haja um pouco de exagero mas será esse o futuro se não houver consciencia mundial para o que fazemos hoje.
Se alguém quiser posso arranjar maneira de "emprestar" o dvd para terem ideia do que Al Gore tenta mostrar.

Mas como nem tudo são más noticias...

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Re: Tópico do Ambiente!

Mensagempor DoctorDre » segunda Oct 13, 2008 11:18 am

:ROFL:

Aqui fica uns videos mais cientificos...

The Big Chill (BBC - +/-50min)

1/5


2/5


3/5


4/5


5/5
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Re: EcoTópico!

Mensagempor jcmarques » sexta Oct 24, 2008 11:48 am

andre_carneiro Escreveu:
Mr Strangelet Escreveu:Vi ontem este carro no TV Turbo!
Este é o primeiro carro totalmente electrico com um design verdadeiramente apaixonante :shock: Em 2011 gostava de ter € para comprar um :D


30000€ ou 20000£ ;)

Não é nada caro segundo se antecipa!


Talvez seja esse o preço mas penso que se é mesmo importante tirar os vehiculos que poluiam o ambiente então os preços de estes carros devia ser menor, mas ai ja é outra conversa... existe tambem as materias primas e o preço de construcçao do mesmo... em fim, vamos la ver e esperar por mais novidades
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Re: EcoTópico!

Mensagempor DoctorDre » sexta Oct 24, 2008 1:20 pm

Noticia antiga do Carro ecológico Tuga... o EcoVinci...

A Retroconcept já está a desenvolver o primeiro automóvel ecológico Português, o Eco Vinci. É o resultado de um protocolo entre a Câmara Municipal do Porto, a Agência de Energia do Porto e a Retroconcept.

Este veículo corresponde a um conceito inovador de locomoção, pensado para a utilização pública ou privada, movido por propulsão eléctrica e com uma forte interacção entre o utilizador e a cidade, através de sistemas inteligentes que serão desenvolvidos pela a IT-Automotive - Sistemas Interactivos para a Automoção e pela Microsoft Automotive.

O Eco Vinci será totalmente construído em Portugal pela Retroconcept e desenvolvido pelo Centro de Engenharia da Maia, através do Laboratório Europeu de Mobilidade Sustentada aí sedeado.

A assinatura deste protocolo decorrerá amanhã (dia 20 de Setembro) na Sala D. Maria dos Paços do Concelho.


Numca mais se ouviu mais nada!
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Re: EcoTópico!

Mensagempor jonhdoe » sexta Oct 24, 2008 1:50 pm

Eco Vinci não conheço, o que conheço é o Vinci GT que de ecológico não tem nada senão leia-se:

"O vinci GT tem capacidade para dois passageiros e está equipado com um motor dianteiro de 6 litros, oito cilindros em V e 480cv às 6000 rotações por minuto, capaz de alcançar uma velocidade máxima de 310km/h. Acelera dos zero aos 100km/h em 4,8 segundos, dsipondo de tracção posterior, de uma caixa de 4 velocidades (???? caixa de 4 deve ser um erro do jornalista) e de travões de disco ventilados às 4 rodas. O depósito tem capacidade para 70 litros de gasolina."

É o mesmo motor que equipa os Viper SRT10...

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Re: EcoTópico!

Mensagempor jcmarques » sexta Oct 24, 2008 2:12 pm

my god :shock:
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Re: EcoTópico!

Mensagempor CesarGomes » sexta Oct 24, 2008 2:15 pm

Eu não percebo estes gajos! Lançam-se no mercado dos automóveis e vão logo atacar o segmento dos carrões desportivos. É a mania de imitar os italianos ou os ingleses, só que estes prosperaram na época de ouro, agora está quieto. Ainda por cima não tem nome nem fama. Toca mas é a desenvolver utilitários e familiares para a malta.
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