O hidrogênio como fonte de combustível para veículos

Da revista Pequenas Empresas Grandes Ideias

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O hidrogênio é nosso

Revista PEGN

O QUE É: O Brasil inaugurou uma nova era para o transporte público com a utilização do hidrogênio como combustível. Desde o mês de julho, o país passou a ter um dos primeiros ônibus desse gênero no mundo — no trajeto São Bernardo do Campo-São Paulo. Até 2010, outros três coletivos serão operados pela Empresa Metropolitana de Transportes Urbanos (EMTU)

COMO FUNCIONA: O ônibus utiliza células de hidrogênio combinadas com baterias de íon-lítio para movimentar motores elétricos. O veículo brasileiro combina dois conjuntos de uso automotivo, que geram 230 kW de potência. Faz sete quilômetros por quilo de gás, o que lhe dá uma autonomia de 350 quilômetros

>>> COMBUSTÍVEL SEM CRISE
Para o abastecimento, a EMTU instalou, com auxílio da Petrobras, uma unidade de produção do gás por eletrólise, que usa apenas água e eletricidade. O custo, segundo a Tuttotrasporti, é de R$ 1 por quilo — ou seja, dá para encher o tanque por R$ 45

>>> QUALIDADE DO AR
A emissão do motor se limita a vapor d’água, gerado pela reação do hidrogênio com o oxigênio dentro das células

Reportagem completa aqui: Edição 249 – Outubro/2009

Rato gigante encontrado em ‘lost volcano’

By Matt Walker
Editor, Earth News

A new species of giant rat has been discovered deep in the jungle of Papua New Guinea.

The rat, which has no fear of humans, measures 82cm long, placing it among the largest species of rat known anywhere in the world.

The creature, which has not yet been formally described, was discovered by an expedition team filming the BBC programme Lost Land of the Volcano.

It is one of a number of exotic animals found by the expedition team.

Like the other exotic species, the rat is believed to live within the Mount Bosavi crater, and nowhere else.

“This is one of the world’s largest rats. It is a true rat, the same kind you find in the city sewers,” says Dr Kristofer Helgen, a mammalogist based at the Smithsonian National Museum of Natural History who accompanied the BBC expedition team.

Initially, the giant rat was first captured on film by an infrared camera trap, which BBC wildlife cameraman Gordon Buchanan set up in the forest on the slopes of the volcano.

The expedition team from the BBC Natural History Unit recorded the rat rummaging around on the forest floor, and were awed by its size.

Immediately, they suspected it could be a species never before recorded by science, but they needed to see a live animal to be sure.

Then trackers accompanying the team managed to trap a live specimen.

“I had a cat and it was about the same size as this rat,” says Buchanan.

The trapped rat measured 82cm in length from its nose to its tail, and weighed approximately 1.5kg.

It had a silver-brown coat of thick long fur, which the scientists who examined it believe may help it survive the wet and cold conditions that can occur within the high volcano crater. The location where the rat was discovered lies at an elevation of over 1,000m.

Initial investigations suggest the rat belongs to the genus Mallomys, which contains a handful of other out-sized species.

It has provisionally been called the Bosavi woolly rat, while its scientific name has yet to be agreed.

The giant rat was first sighted using an infrared camera trap

Other rodents, the group of animals that includes rats, grow to a bigger size.

For example, the largest rodent of all is the capybara, which lives in or near freshwater in South America.

It can grow up to 130cm long and weigh up to 65kg.

The Philippines is also home to a few species of cloud rat which can reach

over 2kg in weight.

But of the true rats, which includes urban brown and black rats that belong to the genus Rattus, few can match the new species.

In 2007, an expedition to New Guinea led by Conservation International discovered another closely related giant woolly rat, which can weigh up to 1.4kg. It also belongs within the genus Mallomys.

However, that species lives in the Foja Mountains, part of the Mamberamo Basin.

Mount Bosavi, where the new rat was found, is an extinct volcano that lies deep in the remote Southern Highlands of Papua New Guinea.

The expedition team entered the crater to explore pristine forest, where few humans have set foot.

Even members of the Kasua tribe, who acted as trackers for the expedition, live outside the crater, which is 4km wide and has walls up to 1km high, trapping the creatures that live within.

The island which includes Papua New Guinea and New Guinea is famous for the number and diversity of the rats and mice that live there.

Over 57 species of true “Murid” rats and mice can be found on the island. The larger rats are often caught by hunters and eaten.

Broadcast of The Lost Land of the Volcano series will begin on BBC One on Tuesday 8 September at 2100 BST. The discovery of the Bosavi woolly rat is broadcast as part of the series on BBC One on Tuesday 22 September.

BBC NEWS | Environment | Ice sheet melt threat reassessed

By Mark Kinver

Science and environment reporter, BBC News

A 3.3m sea level rise will still have a devastating impact on coastal areas

The collapse of a major polar ice sheet will not raise global sea levels as much as previous projections suggest, a team of scientists has calculated.

Writing in Science, the researchers said that the demise of the West Antarctic Ice Sheet WAIS would result in a sea level rise of 3.3m 10 ft.

Previous estimates had forecast a rise in the region of five to six metres.

However, they added, the rise would still pose a serious threat to major coastal cities, such as New York.

“Sea level rise is considered to be the one of the most serious consequence of climate change,” lead author Jonathan Bamber told the Science podcast.

“A sea level rise of just 1.5m would displace 17 million people in Bangladesh alone,” he added.

“So it is of the utmost importance to understand the potential threats to coastlines and people living in coastal areas.”

Threat reassessed

Professor Bamber, from the University of Bristol’s Glaciology Centre, said that the WAIS posed “potentially one of the most serious threats”.

The world has three ice sheets, Greenland, East Antarctica and West Antarctica, but it is the latter that is considered most vulnerable to climatic shifts.

“It has been hypothesised for more than 30 years now that the WAIS is inherently unstable,” he explained.

“This instability means that the ice sheet could potentially rapidly collapse or rapidly put a lot of ice into the oceans.”

When the idea first emerged in the late 1970s, it was estimated that global sea level would rise by five metres if the WAIS collapsed.

Current projections suggest that a complete collapse of WAIS would result in an increase of up to six metres.

But Professor Bamber said that no-one had revisited the calculation, despite new data sets becoming available, and scientists developing a better understanding of the dynamics in the vast ice sheets.

The original estimates were based on “very basic ice thickness data”, he explained.

“Ice thickness data gives you information about the depth of the bedrock underneath the ice sheet.

“Over the past 30 years, we have acquired much more ice thickness data over the whole of Antarctica, particularly over West Antarctica.

“We also have much better surface topography. Those two data sets are critical in determining two things.”

The first was knowing the volume of ice that could contribute to sea level rise, and the second was a better understanding of the proportion of WAIS that was potentially susceptible to this instability.

Instead of assuming that the entire WAIS would collapse, causing sea level to rise by up to six metres, Professor Bamber and colleagues used models based on glaciological theory to simulate how the 2.2 million-cubic-km ice sheet would respond.

“Our reassessment of West Antarctica’s contribution to sea level rise if the ice sheet was to collapse is about 3.3 metres,” he said.

“That is about half of the value that has been quoted up until now.”

The team’s study also calculated what regions were likely to experience the biggest increases in sea level.

“Sea level rise is not uniform across the world’s oceans, partly as a result of disruptions to the Earth’s gravity field,” explained Professor Bamber.

“It turns out that the maximum increase in sea level rise is centred at a latitude of about 40 degrees along the Atlantic and Pacific seaboards of North America.”

This would include cities such as San Francisco and New York.

These areas could expect increases of one-and-a-quarter times the global average, the team estimated.

In other words, if the global average was one metre, then places like New York could expect to see a rise of 1.25m.

Responding to Professor Bamber’s paper in Science, British Antarctic Survey science leader Dr David Vaughan described the findings as “quite sound”.

“But for me, the most crucial question is not solely about the total amount of ice in West Antarctica, because that might take several centuries to be lost to the ocean,” he told BBC News.

“The crucial question is how much ice could be lost in 100-200 years; that’s the sea level rise we have to understand and plan for.

“Even with this new assessment the loss of a fraction of WAIS over those timescales would have serious consequences and costs that we’ve only really just begun to understand.”

Marie-Monique Robin – “A Monsanto não é confiável”

Boa reportagem da Época. A Monsanto tem muita história. Que contem os plantadores de algodão na ìndia. Mas não precisa acreditar em mim, a internet é um campo vasto e fértil, plantado com muita informação.

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Documentarista diz que maior empresa de sementes vende produtos tóxicos e ameaça cientistas

Juliana Arini

A documentarista francesa Marie-Monique Robin, autora de O Mundo Segundo a Monsanto, dedicou três anos de sua vida para desvendar como uma indústria de químicos virou a maior companhia mundial de sementes geneticamente modificadas (transgênicas) e uma das empresas mais influentes do planeta, segundo a revista Business Week. Marie trabalha há 25 anos com matérias investigativas e recebeu prêmios como o Albert Londres, em 1995, concedido a um documentário sobre o tráfico internacional de órgãos. Em 2004, ela foi aclamada na Europa ao produzir o também premiado Esquadrões da Morte: a escola francesa, sobre a relação do governo francês com ditaduras da Amérioca Latina, nos anos 70. Para escrever a história da Monsanto, Marie analisou 500 mil páginas de documentos e viajou à Grã-Bretanha, Estados Unidos, Índia, México, Brasil, Vietnã e Noruega. A escritora fala a ÉPOCA sobre o seu último livro. Procurada pela reportagem, a Monsanto afirma que “agricultores enxergam um benefício no cultivo de seus produtos”. (clique aqui para ler a resposta completa da empresa).

ENTREVISTA – MARIE-MONIQUE ROBIN

QUEM É Documentarista e jornalista francesa. Seu documentário que denuncia táticas do serviço secreto francês e conexões com a repressão na América do Sul foi premiado pelo Senado da França. O QUE FEZ Já publicou livros denunciando uma rede internacional de tráfico de órgãos e a prática da tortura na Guerra da Argélia. O Mundo Segundo a Monsanto virou um documentário feito pela agência de cinema do Canadá. Para investigar a história, passou cinco anos levantando 500 mil páginas de documentos e viajando para Grã-Bretanha, Índia, México, Paraguai, Brasil, Vietnã, Noruega e Itália

ÉPOCA – Existem outras companhias que também desenvolvem a biotecnologia e possuem patentes sobre sementes. Por que fazer um livro exclusivamente sobre a Monsanto?
Marie-Monique Robin - Há cinco anos, quando trabalhava em três documentários sobre biodiversidade e os organismos geneticamente modificados – e ainda acreditava que eles não teriam problemas – eu acabei viajando muito. Fui para Canadá, México, Argentina, Brasil e Índia, e em todas essas regiões eu sempre encontrava denúncias contra a Monsanto. Foi quando eu decidi buscar quem é essa companhia que agora é a maior produtora de biotecnologia e de alimentos geneticamente modificados do planeta.

Debate: Créditos de Carbono desestimulam mudanças de base

Na revista online Economist, um debate me chamou a atenção e vou repassá-lo aos leitores.

Ambos argumentos são valiosos e se sustentam muito bem, no entanto o propósito é provocar o pensamento e o exame da questão.

Será mesmo que o sistema de créditos de carbono é um atenuador da consciência e provoca uma atitude passiva dos inspetores, provocando um descaso nos grandes emissores de carbono e desestimulando mudanças de base? Mr Michael Wara acha que sim.

Ou será que o sistema de troca é realmente eficiente e as acusações de que os relatórios de alguns países são fraudulentos são suposições infundadas? Mr Henry Derwent apresenta uma forte introdução ao defender sua posição, embora pragmática ao fazer frente aos argumentos de Wara.

Para entender o debate:

A Economist argumenta que acredita que o sistema de créditos de carbono é ineficiente. Isto é o que se chama em inglês de Proposition. A pessoa que defende a proposta Defends the proposition. A outra pessoa, que acredita que a proposta está errada, isto é, entende que o sistema de créditos de carbono é uma ferramenta real e eficiente é Against the proposition.

Alimente seu pensamento.

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Rebuttal statements

Defending the proposition

Mr Michael Wara

Assistant Professor at Stanford Law School

Human institutions, and their limits, matter. We need strategies that dramatically reduce greenhouse gases (GHGs) and that are possible to implement effectively. Carbon offsets fail this test.

Against the proposition

Mr Henry Derwent

President and CEO, International Emissions Trading Association

Many of the arguments against carbon offsets derive from an assumption or a set of evidence that some emissions reductions from outside the jurisdiction of a cap-and-trade system, used to offset emissions within that system, are fraudulent.

The moderator’s rebuttal remarks

Dec 9th 2008 | Ms Emma Duncan

You can tell from the statements so far not only that we have two top-class brains applying themselves to the problem, but also that both men believe passionately that their argument, if fed into global policy, will help avert serious climate change. And you can tell from the number and quality of comments that there are a lot of other clever people out there who mind a great deal about the issue too.

Michael Wara’s case is based largely on what he regards as a conceptual problem with offsets: that, in order for them to reduce emissions efficiently, they must represent a reduction over and above what would anyway have happened. Avoiding what he calls the “anyway” credit is known as the additionality principle. He reckons that the additionality principle is impossible to implement because it involves knowing the counterfactual—what would have happened otherwise.

Henry Derwent initially makes a largely theoretical case for offsets, but subsequently counters Mr Wara with pragmatism. He accepts that there are difficulties in the design and implementation of offset systems. The reliance on an absent counter-factual is a problem, but that arises in all sorts of areas. Any government grant, for instance, relies on the assumption that the firm would not have put up the factory otherwise. And, he says, there is no greater reason to assume that foreign reductions will be impossible to monitor than there is to say that the foreign operations of companies will be inherently unreliable.

Mr Derwent has some support among the audience. Sliptitin, for instance, is something of a pragmatist. He is not entirely convinced by offsetting, but he reckons that paying developing countries to cut emissions will have long-term benefits. “Luring China and India in through a system that does some good (albeit with defects),” he says, “ultimately gets these major emitters on the hook for a genuine cap.” Shankarkv takes the broad view that, although the system may have flaws, “trying to perfect a system is easier than trying to start a perfect system.”

So far, however, most of the audience is with Mr Wara. The general view is that the system is too susceptible to fraud. Joaquin Gutierrez makes a point which will resonate with anybody, like me, who has developed a deep loathing for the Common Agricultural Policy: “Have not we, Europeans, learnt enough of market mismanagement and corruption with agricultural goods” to be sceptical of any system that is designed and implemented by governments?

To my mind, Mr Derwent’s strongest argument is that abandoning offsets will mean higher costs, and higher costs mean less emissions reduction. Those who decide, in the end, to support the motion need to satisfy themselves that not just offsetting is flawed, but also that there is a better alternative.