MACKENZIE RIVER DELTA, Northwest Territories — Only a squawk from a
sandhill crane broke the Arctic silence — and a low gurgle of bubbles,
a watery whisper of trouble repeated in countless spots around the
"On a calm day, you can see 20 or more `seeps' out
across this lake," said Canadian researcher Rob Bowen, sidling his
small rubber boat up beside one of them. A tossed match would have set
"It's essentially pure methane."
gas bubbling up from underwater vents, escaping into northern skies,
adds to the global-warming gases accumulating in the atmosphere. And
pure methane escaping in the massive amounts known to be locked in the
Arctic permafrost and seabed would spell a climate catastrophe.
Is such an unlocking under way?
say air temperatures here in northwest Canada, in Siberia and elsewhere
in the Arctic have risen more than 2.5 C (4.5 F) since 1970 — much
faster than the global average. The summer thaw is reaching deeper into
frozen soil, at a rate of 4 centimeters (1.5 inches) a year, and a
further 7 C (13 F) temperature rise is possible this century, says the
authoritative, U.N.-sponsored Intergovernmental Panel on Climate Change
In 2007, air monitors detected a rise in methane
concentrations in the atmosphere, apparently from far northern sources.
Russian researchers in Siberia expressed alarm, warning of a potential
surge in the powerful greenhouse gas, additional warming of several
degrees, and unpredictable consequences for Earth's climate.
say massive seeps of methane might take centuries. But the Russian
scenario is disturbing enough to have led six U.S. national
laboratories last year to launch a joint investigation of rapid methane
release. And IPCC Chairman Rajendra Pachauri in July asked his
scientific network to focus on "abrupt, irreversible climate change"
from thawing permafrost.
The data will come from teams like one
led by Scott Dallimore, who with Bowen and others pitched tents here on
the remote, boggy fringe of North America, 2,200 kilometers (1,400
miles) from the North Pole, to learn more about seeps in the 25,000
lakes of this vast river delta.
A "puzzle," Dallimore calls it.
factors are poorly studied, so we're really doing frontier science
here," the Geological Survey of Canada scientist said. "There is a very
large storehouse of greenhouse gases within the permafrost, and if that
storehouse of greenhouse gases is fluxing to the surface, that's
important to know. And it's important to know if that flux will change
Permafrost, tundra soil frozen year-round and
covering almost one-fifth of Earth's land surface, runs anywhere from
50 to 600 meters (160 to 2,000 feet) deep in this region. Entombed in
that freezer is carbon — plant and animal matter accumulated through
As the soil thaws, these ancient deposits finally
decompose, attacked by microbes, producing carbon dioxide and — if in
water — methane. Both are greenhouse gases, but methane is many times
more powerful in warming the atmosphere.
Researchers led by the
University of Florida's Ted Schuur last year calculated that the top 3
meters (10 feet) of permafrost alone contain more carbon than is
currently in the atmosphere.
"It's safe to say the surface
permafrost, 3 to 5 meters, is at risk of thawing in the next 100
years," Schuur said by telephone from an Alaska research site. "It
can't stay intact."
Methane also is present in another form, as
hydrates — ice-like formations deep underground and under the seabed in
which methane molecules are trapped within crystals of frozen water. If
warmed, the methane will escape.
Dallimore, who has long
researched hydrates as energy sources, believes a breakdown of such
huge undersea formations may have produced conical "hills" found
offshore in the Beaufort Sea bed, some of them 40 meters (more than 100
With underwater robots, he detected methane gas
leaking from these seabed features, which resemble the strange hills
ashore here that the Inuvialuit, or Eskimos, call "pingos." And because
the coastal plain is subsiding and seas are rising from warming, more
permafrost is being inundated, exposed to water warmer than the air.
methane seeps that the Canadians were studying in the Mackenzie Delta,
amid grassy islands, steel-gray lakes and summertime temperatures well
above freezing, are saucer-like indentations just 10 meters (30 feet)
or so down on the lake bed.
The ultimate source of that gas —
hydrates, decomposition or older natural gas deposits — is unclear, but
Dallimore's immediate goal is quantifying the known emissions and
finding the unknown.
With tent-like, instrument-laden enclosures
they positioned over two seeps, each several meters (yards) wide, the
researchers have determined they are emitting methane at a rate of up
to 0.6 cubic meters (almost 1 cubic yard) per minute.
team is also monitoring the seeps with underwater listening devices, to
assess whether seasonal change — warming — affects the emissions rate.
Even if the lake seeps are centuries old, Bowen said, the question is, "Will they be accelerated by recent changes?"
A second question: Are more seeps developing?
begin answering that, Dallimore is working with German and Canadian
specialists in aerial surveying, teams that will fly over swaths of
Arctic terrain to detect methane "hot spots" via spectrometric imagery,
instruments identifying chemicals by their signatures on the light
Research crews are hard at work elsewhere, too, to get a handle on this possible planetary threat.
and others are trying to take field observations and get it scaled up
to global models," said Alaska researcher Schuur. From some 400
boreholes drilled deep into the tundra worldwide, "we see historic
warming of permafrost. Much of it is now around 2 below zero (28 F),"
A Coast Guard C-130 aircraft is overflying Alaska
this summer with instruments sampling the air for methane and carbon
dioxide. In parts of Alaska, scientists believe the number of
"thermokarst" lakes — formed when terrain collapses over thawing
permafrost and fills with meltwater — may have doubled in the past
three decades. Those lakes then expand, thawing more permafrost on
their edges, exposing more carbon.
Off Norway's Arctic
archipelago of Svalbard last September, British scientists reported
finding 250 methane plumes rising from the shallow seabed. They're
probably old, scientists said, but only further research can assess
whether they're stable. In March, Norwegian officials did say methane
levels had risen on Svalbard.
Afloat above the huge, shallow
continental shelf north of Siberia, Russian researchers have detected
seabed "methane chimneys" sending gas bubbling up to the surface,
possibly from hydrates.
Reporting to the European Geophysical
Union last year, the scientists, affiliated with the University of
Alaska and the Russian Academy of Sciences, cited "extreme" saturation
of methane in surface waters and in the air above. They said up to 10
percent of the undersea permafrost area had melted, and it was "highly
possible" that this would open the way to abrupt release of an
estimated 50 billion tons of methane.
Depending on how much
dissolved in the sea, that might multiply methane in the atmosphere
several-fold, boosting temperatures enough to cause "catastrophic
greenhouse warming," as the Russians called it. It would be
self-perpetuating, melting more permafrost, emitting more methane.
might label that alarmism. And Stockholm University researcher Orjan
Gustafsson, a partner in the Russians' field work, acknowledged that
"the scientific community is quite split on how fast the permafrost can
But there's no doubt the north contains enough potential
methane and carbon dioxide to cause abrupt climate change, Gustafsson
said by telephone from Sweden.
Canada's pre-eminent permafrost
expert, Chris Burn, has trekked to lonely locations in these high
latitudes for almost three decades, meticulously chronicling the
changes in the tundra.
On a stopover at the Aurora Research
Institute in the Mackenzie Delta town of Inuvik, the Carleton
University scientist agreed "we need many, many more field
observations." But his teams have found the frozen ground warming down
to about 80 meters, and he believes the world is courting disaster in
failing to curb warming by curbing greenhouse emissions.
lost just 1 percent of the carbon in permafrost today, we'd be close to
a year's contributions from industrial sources," he said. "I don't
think policymakers have woken up to this. It's not in their risk
How likely is a major release?
"I don't think it's a case of likelihood," he said. "I think we are playing with fire."