News & Current Affairs

September 6, 2008

Minor quake jolts Oakland, California

Minor quake jolts Oakland, California

SAN FRANCISCO, California (Expressyoureself) — A magnitude 4.0 earthquake struck east of Oakland, California, at around 9 p.m. ET Friday, according to the U.S. Geological Survey.

The quake’s epicenter was about 10 miles (16 kilometers) below the surface, the USGS reported.

Residents said they felt a sharp jolt, saw plants sway and dishes rattle.

There were no initial reports of damage or injuries.

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September 5, 2008

Sea level rise by 2100 ‘below 2m’

Sea level rise by 2100 ‘below 2m’

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Thames Barrier in the evening

A revamp of the Thames Barrier is likely as sea levels rise

Sea levels globally are very unlikely to rise by more than 2m (7ft) this century, scientists conclude.

Major increases would have to be fuelled by a faster flow of glaciers on the Greenland or Antarctic ice sheets.

But writing in the journal Science, a US team concludes that a rise of 2m would need glaciers to reach speeds that are “physically untenable”.

However, even increases substantially less than 2m would cause major issues for many societies, they say.

“Even a sea level rise of 20cm (8in) in a century will have quite dramatic implications,” said Shad O’Neel from the US Geological Survey (USGS).

Woe betide any government that thinks a 2m rise in sea level isn’t something to take notice of
Dr David Vaughan
British Antarctic Survey

“This work is in no way meant to undermine the seriousness of climate change, and sea level rise is something we’re going to have to deal with,” he told.

Al Gore’s documentary An Inconvenient Truth received some criticism for implying that a rise of 20ft (6m) was possible in the near future, although it did not give a definite timeframe.

By contrast, this latest research tallies broadly with the conclusions of other groups that have examined the question using different approaches.

Fast work

In its landmark assessment of climate change published last year, the Intergovernmental Panel on Climate Change (IPCC) concluded that sea level rise would probably fit in the range between 28 and 43cm over the century, although 59cm was a possibility.

The current rate is about 3mm per year.

But the IPCC specifically excluded the mechanism able to produce the biggest amounts of water quickly – acceleration in the flow of ice from the Greenland and Antarctic ice sheets, the world’s two major ice masses that would between them raise sea levels by about 70m if they completely melted.

Most of the ice comes off in glaciers. Scientists know that many of the glaciers have accelerated in recent years – some quite spectacularly. The Jakobshavn glacier in Greenland, for example, doubled its speed in six years to about 12km per year.

Antarctic glacier

The acceleration of glaciers is not well understood

But the processes involved are poorly understood, and the IPCC concluded that on that basis it would be unreasonable to draw any conclusions about how far the acceleration might go.

Individual scientists, however, have not be so coy. The team behind the current research looked at what we do know about Greenlandic and Antarctic glaciers, about the rates of flow and the factors that might prevent acceleration.

“We don’t really know a speed limit for glaciers,” said Dr O’Neel, “but we can look at what we have today and ask ‘what would happen if they all behaved like Jakobshavn?’

“It’s been going fast for several years now and hasn’t gone another marked increase in speed. Helheim had a brief period at 14km per year, Columbia at nine or 10; so that kind of figure, in the region of 10km/year, seems to be about as fast as it gets.”

To achieve a 2m sea level rise by 2100, by contrast, every Greenland glacier would have to increase its flow rate to at least 27km per year and remain at that velocity for the rest of the century.

‘Scary’ scenario

Antarctica is rather different. The West Antarctic Ice Sheet rests on rock that is mainly below sea level, meaning that warming seas could increase the rate of ice loss, though again the new analysis suggests this is also very unlikely to result in a catastrophic melt during this century.

David Vaughan from the British Antarctic Survey believes the US team has got its figures about right.

“The point is that whatever happens in this century can only start from present conditions and present rates of sea level rise, and that constrains the rise that can occur this century,” he told.

“However, if you’re looking further ahead than 2100 – and many governments are, including the Netherlands and the UK which are thinking about infrastructure that would last more than 100 years – then that second century still looks quite scary.

“I certainly don’t disagree with them that we shouldn’t be making outlandish statements about sea level rise, and some outlandish statements have been made; but the high end of the estimates here is still about 2m, and woe betide any government that thinks a 2m rise in sea level isn’t something to take notice of.”

August 14, 2008

Arsenic-munching bacteria found

Arsenic-munching bacteria found

Bacteria(USGS)

Microbial biofilms form in rocky pools, fed by hot springs containing arsenic

In the warm, bubbling pools of Mono Lake in California, scientists have isolated a bacterium that fuels itself on arsenic.

Combining light and arsenic, these bacteria make their food and multiply using a chemical that is toxic to most other life forms.

The researchers think using arsenic as an energy source was a process used by ancient bacteria.

Their findings are reported in the journal Science.

Ronald Oremland of the US Geological Survey explained that these bacteria are photosynthetic, using sunlight – like plants – to turn carbon dioxide into food.

What is different about them is that instead of using water in this process, they use arsenic.

The US-based researchers isolated the bacterium from the lake, which lies at the foot of the Sierra Nevada.

Colour film

“These lakes are fed by hydrothermal waters that leach out arsenic-containing minerals from the surrounding rocks,” Dr Oremland told.

The researchers noticed that the bacteria had colonised small, hot pools, forming colorful “biofilms”.

MonoLake(USGS)

Bacteria living in Mono Lake, California can survive the high levels of arsenic

“We suspected that these bacteria were using arsenic to make a living, so we scraped the biofilms off the rock and studied them under laboratory conditions.”

By first withholding light, then arsenic, the team showed that the bacteria required both to grow.

This the first time an organism has been found that can use arsenic to photosynthesise under anaerobic conditions, Dr Oremland believes.

He suspects that this is an ancient ability in bacteria.

“We think that bacteria were photosynthesising before oxygen was present in the atmosphere,” he said.

Primordial niche

Understanding how arsenic is metabolized by bacteria could help scientists comprehend its damaging affects inside human cells.

Worldwide, 144 million people are exposed to toxic levels of arsenic in their drinking water.

It enters the body’s cells by diffusion; and once inside, it disrupts how they function by binding to their machinery, inactivating it, and disrupting the way energy is transported.

Long-term exposure can lead to skin disease and kidney and bladder cancer, and it is thought to stunt the intellectual development of children.

The most arsenic-contaminated regions are in India, Pakistan, and China, where soluble arsenic in ground waters is above the World Health Organization’s (WHO) suggested maximum safe level of 10 parts per billion.

August 6, 2008

Arctic Map shows dispute hotspots

Arctic Map shows dispute hotspots

VIEW THE MAP
Durham University)
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British scientists say they have drawn up the first detailed map to show areas in the Arctic that could become embroiled in future border disputes.

A team from Durham University compiled the outline of potential hotspots by basing the design on historical and ongoing arguments over ownership.

Russian scientists caused outrage last year when they planted their national flag on the seabed at the North Pole.

The UK researchers hope the map will inform politicians and policy makers.

“Its primary purpose is to inform discussions and debates because, frankly, there has been a lot of rubbish about who can claim (sovereignty) over what,” explained Martin Pratt, director of the university’s International Boundaries Research Unit (IBRU).

“To be honest, most of the other maps that I have seen in the media have been very simple,” he added.

“We have attempted to show all known claims; agreed boundaries and one thing that has not appeared on any other maps, which is the number of areas that could be claimed by Canada, Denmark and the US.”

Energy security is driving interest, as is the fact that Arctic ice is melting more and more during the summer
Martin Pratt,
Durham University

The team used specialist software to construct the nations’ boundaries, and identify what areas could be the source of future disputes.

“All coastal states have rights over the resources up to 200 nautical miles from their coastline,” Mr Pratt said. “So, we used specialist geographical software to ‘buffer’ the claims out accurately.”

The researchers also took into account the fact that some nations were able to extend their claims to 350 nautical miles as a result of their landmasses extending into the sea.

Back on the agenda

The issue of defining national boundaries in the Arctic was brought into sharp relief last summer when a team of Russian explorers used their submarine to plant their country’s flag on the seabed at the North Pole.

A number of politicians from the nations with borders within the Arctic, including Canada’s foreign minister, saw it as Moscow furthering its claim to territory within the region.

Mr Pratt said a number of factors were driving territorial claims back on to the political agenda.

“Energy security is driving interest, as is the fact that Arctic ice is melting more and more during the summer,” he told BBC News. “This is allowing greater exploration of the Arctic seabed.”

Data released by the US Geological Survey last month showed that the frozen region contained an estimated 90 billion barrels of untapped oil.

Mr Pratt added that the nations surrounding the Arctic also only had a limited amount of time to outline their claims.

“If they don’t define it within the timeframe set out by the UN Convention on the Law of the Sea, then it becomes part of what is known as ‘The Area’, which is administered by the International Seabed Authority on behalf of humanity as a whole.”

August 5, 2008

New quake hits Chinese province

An earthquake with a magnitude of 6.0 has struck Sichuan province in China, the US Geological Survey says.

The quake struck just before 1800 (1000 GMT), 48km (30 miles) north-west of Guangyuan city, and occurred at a depth of 10km (6.2 miles), the agency said.

No injuries have been reported from the scene. In May, about 70,000 people died when an 7.9 magnitude earthquake struck Sichuan province.

Since then, thousands of aftershocks have rattled the region.

The epicentre of Tuesday’s earthquake was some 1,253km (778 miles) south-west of the Chinese capital, Beijing, where the Olympic Games are due to begin on Friday.

Map showing Sichuan province

The quake came a few hours after the Olympic torch was paraded through Sichuan’s provincial capital, Chengdu, the last leg of its journey before it returns to Beijing for the opening ceremony.

The state media agency Xinhua said the tremors were felt in Chengdu.

Major reconstruction efforts have been under way in Sichuan province since the 12 May earthquake left about five million people homeless.

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