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15
Dez 14

Vast methane 'plumes' seen in Arctic Ocean as sea ice retreats
(THE INDEPENDENT – SATURDAY – 13 DECEMBER 2014 – STEVE CONNOR – SCIENCE)

 

Pg-2-arctic-graphic.jpg

 

Dramatic and unprecedented plumes of methane - a greenhouse gas 20 times more potent than carbon dioxide - have been seen bubbling to the surface of the Arctic Ocean by scientists undertaking an extensive survey of the region.

 

The scale and volume of the methane release has astonished the head of the Russian research team who has been surveying the seabed of the East Siberian Arctic Shelf off northern Russia for nearly 20 years.

 

In an exclusive interview with The Independent, Igor Semiletov of the International Arctic Research Centre at the University of Alaska Fairbanks, who led the 8th joint US-Russia cruise of the East Siberian Arctic seas, said that he has never before witnessed the scale and force of the methane being released from beneath the Arctic seabed.

 

"Earlier we found torch-like structures like this but they were only tens of metres in diameter. This is the first time that we've found continuous, powerful and impressive seeping structures more than 1,000 metres in diameter. It's amazing," Dr Semiletov said.

 

"I was most impressed by the sheer scale and the high density of the plumes. Over a relatively small area we found more than 100, but over a wider area there should be thousands of them," he said.

 

Scientists estimate that there are hundreds of millions of tons of methane gas locked away beneath the Arctic permafrost, which extends from the mainland into the seabed of the relatively shallow sea of the East Siberian Arctic Shelf.

 

One of the greatest fears is that with the disappearance of the Arctic sea ice in summer, and rapidly rising temperatures across the entire Arctic region, which are already melting the Siberian permafrost, the trapped methane could be suddenly released into the atmosphere leading to rapid and severe climate change.

 

Dr Semiletov's team published a study in 2010 estimating that the methane emissions from this region were in the region of 8 million tons a year but the latest expedition suggests this is a significant underestimate of the true scale of the phenomenon.

 

In late summer, the Russian research vessel Academician Lavrentiev conducted an extensive survey of about 10,000 square miles of sea off the East Siberian coast, in cooperating with the University of Georgia Athens. Scientists deployed four highly sensitive instruments, both seismic and acoustic, to monitor the "fountains" or plumes of methane bubbles rising to the sea surface from beneath the seabed.

 

"In a very small area, less than 10,000 square miles, we have counted more than 100 fountains, or torch-like structures, bubbling through the water column and injected directly into the atmosphere from the seabed," Dr Semiletov said.

 

"We carried out checks at about 115 stationary points and discovered methane fields of a fantastic scale - I think on a scale not seen before. Some of the plumes were a kilometre or more wide and the emissions went directly into the atmosphere - the concentration was a hundred times higher than normal," he said.

 

Dr Semiletov released his findings for the first time last week at the American Geophysical Union meeting in San Francisco. He is now preparing the study for publication in a scientific journal.

 

The total amount of methane stored beneath the Arctic is calculated to be greater than the overall quantity of carbon locked up in global coal reserves so there is intense interest in the stability of these deposits as the polar region warms at a faster rate than other places on earth.

 

Natalia Shakhova, a colleague at the International Arctic Research Centre at the University of Alaska Fairbanks, said that the Arctic is becoming a major source of atmospheric methane and the concentrations of the powerful greenhouse gas have risen dramatically since pre-industrial times, largely due to agriculture.

 

However, with the melting of Arctic sea ice and permafrost, the huge stores of methane that have been locked away underground for many thousands of years might be released over a relatively short period of time, Dr Shakhova said.

 

"I am concerned about this process, I am really concerned. But no-one can tell the timescale of catastrophic releases. There is a probability of future massive releases might occur within the decadal scale, but to be more accurate about how high that probability is, we just don't know," Dr Shakova said.

 

"Methane released from the Arctic shelf deposits contributes to global increase and the best evidence for that is the higher concentration of atmospheric methane above the Arctic Ocean," she said.

 

"The concentration of atmospheric methane increased unto three times in the past two centuries from 0.7 parts per million to 1.7ppm, and in the Arctic to 1.9ppm. That's a huge increase, between two and three times, and this has never happened in the history of the planet," she added.

 

Each methane molecule is about 70 times more potent in terms of trapping heat than a molecule of carbon dioxide. However, because methane it broken down more rapidly in the atmosphere than carbon dioxide, scientist calculate that methane is about 20 times more potent than carbon dioxide over a hundred-year cycle.

 

(independent.co.uk)

publicado por Produções Anormais - Albufeira às 01:30

02
Ago 14

We are sniffing methane

(The Watchers)

 

Vast methane plumes discovered escaping from the seafloor of Arctic ocean

 

Methane bubbles

 

Just a week into the methane sampling program and SWERUS-C3 Arctic expedition scientists have discovered vast methane plumes escaping from the seafloor of the Laptev continental slope. These early glimpses of what may be in store for a warming Arctic Ocean could help scientists project the future releases of the strong greenhouse gas methane from the Arctic ocean, their press release states.

 

Results of preliminary analyses of seawater samples pointed towards levels of dissolved methane 10–50 times higher than background levels.

 

 

We are sniffing methane

All analysis tells the signs

We are in a Mega flare

We see it in the water column we read it above the surface and we follow it up high into the sky with radars and lasers

We see it mixed in the air and carried away with the winds.

Methane in the air

(Ulf Hedman, Science Coordinator, Swedish Polar Research Secretariat)

 

The discovery was made while the icebreaker Oden crosscut the Laptev Sea along a depth gradient from 1000 m to just 100 m following the continental slope upward to reach the shallow waters of the outer Laptev Sea Shelf.

 

By use of acoustic techniques and geochemical analyses of water samples, the scientists found vast methane plumes escaping from the seafloor at depths between 500 m and 150 m. At several places, the methane “bubbles“ even rose to the ocean surface.

 

(texto/parcial e imagens – The Watchers)

publicado por Produções Anormais - Albufeira às 00:03

11
Ago 12

Meteor smoke makes strange clouds

 

A key ingredient for 'night shining clouds' comes from outer space. Scientists have detected bits of 'meteor smoke' imbedded in them.

 

Noctilucent clouds or NLC in 1880 and 1990 – increasing over time

 

They look alien. The electric-blue ripples and pale tendrils of NLCs reaching across the night sky resemble something from another world.

“We've detected bits of 'meteor smoke' imbedded in noctilucent clouds. This discovery supports the theory that meteor dust is the nucleating agent around which NLCs form.”

 

Noctilucent clouds near the top of Earth's atmosphere

 

Noctilucent clouds are a mystery dating back to the late 19th century. Northern sky watchers first noticed them in 1885 about two years after the eruption of Krakatoa.

"We found that about 3% of each ice crystal in a noctilucent cloud is meteoritic."

When meteoroids hit our atmosphere and burn up, they leave behind a haze of tiny particles suspended 70 km to 100 km above Earth's surface.

The small size of the ice crystals explains the clouds' blue color.

 

How methane, a greenhouse gas, boosts the abundance of water at the top of Earth's atmosphere

 

"When methane makes its way into the upper atmosphere, it is oxidized by a complex series of reactions to form water vapor. This extra water vapor is then available to grow ice crystals for NLCs."
Noctilucent clouds are a sort of "canary in a coal mine" for one of the most important greenhouse gases.

"They might look alien, but they're telling us something very important about our own planet."

 

(NASA)

publicado por Produções Anormais - Albufeira às 13:25

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