“…massive deposits of subsea methane are bubbling to the surface as
the Arctic region becomes warmer and its ice retreats…”

Exclusive: The methane time bomb
BY Steve Connor  /  23 September 2008

The first evidence that millions of tons of a greenhouse gas 20 times
more potent than carbon dioxide is being released into the atmosphere
from beneath the Arctic seabed has been discovered by scientists.

The Independent has been passed details of preliminary findings
suggesting that massive deposits of sub-sea methane are bubbling to
the surface as the Arctic region becomes warmer and its ice retreats.

Underground stores of methane are important because scientists believe
their sudden release has in the past been responsible for rapid
increases in global temperatures, dramatic changes to the climate, and
even the mass extinction of species. Scientists aboard a research ship
that has sailed the entire length of Russia’s northern coast have
discovered intense concentrations of methane – sometimes at up to 100
times background levels – over several areas covering thousands of
square miles of the Siberian continental shelf.

In the past few days, the researchers have seen areas of sea foaming
with gas bubbling up through “methane chimneys” rising from the sea
floor. They believe that the sub-sea layer of permafrost, which has
acted like a “lid” to prevent the gas from escaping, has melted away
to allow methane to rise from underground deposits formed before the
last ice age.

They have warned that this is likely to be linked with the rapid
warming that the region has experienced in recent years.

Methane is about 20 times more powerful as a greenhouse gas than
carbon dioxide and many scientists fear that its release could
accelerate global warming in a giant positive feedback where more
atmospheric methane causes higher temperatures, leading to further
permafrost melting and the release of yet more methane.

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

Orjan Gustafsson of Stockholm University in Sweden, one of the leaders
of the expedition, described the scale of the methane emissions in an
email exchange sent from the Russian research ship Jacob Smirnitskyi.

“We had a hectic finishing of the sampling programme yesterday and
this past night,” said Dr Gustafsson. “An extensive area of intense
methane release was found. At earlier sites we had found elevated
levels of dissolved methane. Yesterday, for the first time, we
documented a field where the release was so intense that the methane
did not have time to dissolve into the seawater but was rising as
methane bubbles to the sea surface. These ‘methane chimneys’ were
documented on echo sounder and with seismic [instruments].”

At some locations, methane concentrations reached 100 times background
levels. These anomalies have been seen in the East Siberian Sea and
the Laptev Sea, covering several tens of thousands of square
kilometres, amounting to millions of tons of methane, said Dr
Gustafsson. “This may be of the same magnitude as presently estimated
from the global ocean,” he said. “Nobody knows how many more such
areas exist on the extensive East Siberian continental shelves.

“The conventional thought has been that the permafrost ‘lid’ on the
sub-sea sediments on the Siberian shelf should cap and hold the
massive reservoirs of shallow methane deposits in place. The growing
evidence for release of methane in this inaccessible region may
suggest that the permafrost lid is starting to get perforated and thus
leak methane… The permafrost now has small holes. We have found
elevated levels of methane above the water surface and even more in
the water just below. It is obvious that the source is the seabed.”

The preliminary findings of the International Siberian Shelf Study
2008, being prepared for publication by the American Geophysical
Union, are being overseen by Igor Semiletov of the Far-Eastern branch
of the Russian Academy of Sciences. Since 1994, he has led about 10
expeditions in the Laptev Sea but during the 1990s he did not detect
any elevated levels of methane. However, since 2003 he reported a
rising number of methane “hotspots”, which have now been confirmed
using more sensitive instruments on board the Jacob Smirnitskyi.

Dr Semiletov has suggested several possible reasons why methane is now
being released from the Arctic, including the rising volume of
relatively warmer water being discharged from Siberia’s rivers due to
the melting of the permafrost on the land.

The Arctic region as a whole has seen a 4C rise in average
temperatures over recent decades and a dramatic decline in the area of
the Arctic Ocean covered by summer sea ice. Many scientists fear that
the loss of sea ice could accelerate the warming trend because open
ocean soaks up more heat from the sun than the reflective surface of
an ice-covered sea.

Örjan Gustafsson
email : orjan.gustafsson [at] itm [dot] su [dot] se

Igor Semiletov
email : igorsmat [at] iarc [dot] uaf [dot] edu

The ultimate gas leak that scientists dreaded
BY Steve Connor  /  23 September 2008

There are two significant facts about methane in terms of global
warming. It is about 20 times more potent as a greenhouse gas than
carbon dioxide, and there are massive stores of it locked away under
the permafrost of the northern hemisphere.

Methane is produced naturally by the decay of water-logged vegetation.
Over thousands of years it has accumulated under the ground at
northern latitudes and has effectively been taken out of circulation
by the permafrost acting as an impermeable lid.

What makes methane so potentially dangerous is that its release from
under the now-leaking permafrost could accelerate global warming,
which in turn would speed the melting of the permafrost and release
even more methane. Scientists believe this has happened in the
geological past with devastating consequences for the global climate
and life.

Like carbon dioxide, average methane concentrations in the atmosphere
have risen significantly since the Industrial Revolution, increasing
from about 700 parts per billion (ppb) in 1800 to about 1,790ppb
today. Much of this increase is down to human activities, notably oil
and gas exploration, and agriculture.

For the past 10 years, average global methane concentrations have
levelled out, probably because of improvements in Russian gas
exploration. However, for the first time in more than a decade,
scientists recorded an increase in global methane in 2007 and are set
to measure a further increase this year.

Scientists at the US National Oceanic and Atmospheric Administration
(NOAA) have identified the Arctic as a potentially important new
source of methane as temperatures in the region increase; it is one of
the most rapidly warming places on Earth. “We’re on the look-out for
the first sign of a methane release from thawing Arctic permafrost.
It’s too soon to tell whether last year’s spike in emissions includes
the start of such a trend,” said NOAA’s methane expert Ed Dlugokencky
last April.

The good news about methane is that it is quickly degraded in the
environment, with an average lifetime of about 12 years, compared to
the 100 years of carbon dioxide. The bad news is that we do not
understand how the methane stores in the north will behave as the
region experiences more extensive thaws. The fear is that the amounts
released will make global warming far worse than expected.

Graham Westbrook
email : g.k.westbrook [at] bham [dot] ac [dot] uk

Hundreds of methane ‘plumes’ discovered
BY Steve Connor  /  25 September 2008

British scientists have discovered hundreds more methane “plumes”
bubbling up from the Arctic seabed, in an area to the west of the
Norwegian island of Svalbard. It is the second time in a week that
scientists have reported methane emissions from the Arctic.

Methane is 20 times more potent than carbon dioxide as a greenhouse
gas and the latest findings from two separate teams of scientists
suggest it is being released in significant amounts from within the
Arctic Circle.

On Tuesday, The Independent revealed that scientists on board a
Russian research ship had detected vast quantities of methane breaking
through the melting permafrost under the seabed of the shallow
continental shelf off the Siberian coast.

Yesterday, researchers on board the British research ship the James
Clark Ross said they had counted about 250 methane plumes bubbling
from the seabed in an area of about 30 square miles in water less than
400 metres (1,300 feet) deep off the west coast of Svalbard. They have
also discovered a set of deeper plumes at depths of about 1,200 metres
at a second site near by. Analysis of sediments and seawater has
confirmed the rising gas is methane, said Professor Graham Westbrook
of Birmingham University, the study’s principal investigator.

“The discovery of this system is important as its presence provides
evidence that methane, which is a greenhouse gas, has been released in
this climactically sensitive region since the last ice age,” Professor
Westbrook said. An analysis of sediments taken from the seabed show
that the gas is coming from methane hydrates – ice-like crystals where
molecules of the gas are captured in “cages” made of water molecules,
which become unstable as water pressures fall or temperatures rise.

Professor Westbrook said the area surveyed off the west coast of
Svalbard was very different to the area being studied by the Russian
vessel because the water was much deeper and does not have a layer of
permafrost sealing the methane under the seabed.

It is likely that methane emissions off Svalbard have been continuous
for about 15,000 years – since the last ice age – but as yet no one
knows whether recent climactic shifts in the Arctic have begun to
accelerate them to a point where they could in themselves exacerbate
climate change, he said.

“We were very excited when we found these plumes because it was the
first evidence there was an active gas system in this part of the
world,” Professor Westbrook said after disembarking from the ship,
which arrived back in Britain yesterday. “Now we know it’s there we
know we have to very seriously consider its effect.”

Antarctic sea ice increases despite warming  /  12 September 2008

The amount of sea ice around Antarctica has grown in recent Septembers
in what could be an unusual side-effect of global warming, experts
say. In the southern hemisphere winter, when emperor penguins huddle
together against the biting cold, ice on the sea around Antarctica has
been increasing since the late 1970s, perhaps because climate change
means shifts in winds, sea currents or snowfall.

At the other end of the planet, Arctic sea ice is now close to
matching a September 2007 record low at the tail end of the northern
summer, in a threat to the hunting lifestyles of indigenous peoples
and creatures such as polar bears. “The Antarctic wintertime ice
extent increased…at a rate of 0.6% per decade” from 1979 to 2006,
says Donald Cavalieri, a senior research scientist at the NASA Goddard
Space Flight Center in Maryland. At 19 million square kilometres, it
is still slightly below records from the early 1970s of 20 million, he
says. Since 1979 however, the average year-round ice extent has risen

Sceptics’ delight
Some climate sceptics point to the differing trends at the poles as a
sign that worries about climate change are exaggerated, but experts
say they can explain the development. “What’s happening is not
unexpected…Climate modellers predicted a long time ago that the
Arctic would warm fastest and the Antarctic would be stable for a long
time,” says Ted Maksym, a sea ice specialist at the British Antarctic

The UN Climate Panel says it is at least 90% sure that people are
stoking global warming – mainly by burning fossil fuels. But it says
each region will react differently. A key difference is that Arctic
ice floats on an ocean and is warmed by shifting currents and winds
from the south. By contrast, Antarctica is an isolated continent
bigger than the US that creates its own deep freeze. “The air
temperature in Antarctica has increased very little compared to the
Arctic,” says Ola Johannessen, director of the Nansen Environmental
and Remote Sensing Center in Bergen, Norway. “The reason is you have a
huge ocean surrounding the land.” Cavalieri says some computer models
indicate a reduction in the amount of heat coming up from the ocean
around Antarctica as one possible explanation for growing ice.

Hot air
Another theory was that warmer air absorbs more moisture and means
more snow and rainfall, he says. That could mean more fresh water at
the sea surface around Antarctica – fresh water freezes at a higher
temperature than salt water. “There has been a strengthening of the
winds that circumnavigate the Antarctic,” says Maksym. That might be
linked to a thinning of the ozone layer high above the continent,
blamed in turn on human use of chemicals used in refrigerants.

In some places, stronger winds might blow ice out to sea to areas
where ice would not naturally form. Maksym predicted that global
warming would eventually warm the southern oceans, and shrink the sea
ice around Antarctica. “A lot of the modellers are predicting the
turning point to be right about this time,” he says.

Edward Maksym
email : emak [at] bas [dot] ac [dot] uk