"So many amplifying methane feedbacks, so little time to stop them all"
The UK’s National Oceanography Centre in Southampton reports:
The warming of an Arctic current over the last 30 years has triggered the release of methane, a potent greenhouse gas, from methane hydrate stored in the sediment beneath the seabed.
German and British scientists “have found that more than 250 plumes of bubbles of methane gas are rising from the seabed of the West Spitsbergen continental margin in the Arctic, in a depth range of 150 to 400 metres” [See figure on right].
Methane released from gas hydrate in submarine sediments has been identified in the past as an agent of climate change. The likelihood of methane being released in this way has been widely predicted.
A lead researcher said, “Our survey was designed to work out how much methane might be released by future ocean warming; we did not expect to discover such strong evidence that this process has already started.”
This is the first time that such behaviour in response to climate change has been observed in the modern period.
While most of the methane currently released from the seabed is dissolved in the seawater before it reaches the atmosphere, methane seeps are episodic and unpredictable and periods of more vigorous outflow of methane into the atmosphere are possible. Furthermore, methane dissolved in the seawater contributes to ocean acididfication.
Geophysics Professor Graham Westbrook warns: “If this process becomes widespread along Arctic continental margins, tens of megatonnes of methane per year – equivalent to 5-10% of the total amount released globally by natural sources, could be released into the ocean.”
For more on this, see the original GRL study here (subs. req’d).
The rest of this post, which reviews some recent findings on the not-so-perma-frost, is a guest blog by Ken Levenson, who blogs at checklisttowardzerocarbon.
The vast amount of carbon stored in the arctic and boreal regions of the world is more than double that previously estimated…
Reported in July of this year, by Science Daily – it’s a staggering amount:
“We now estimate the deposits contain over 1.5 trillion tons of frozen carbon, about twice as much carbon as contained in the atmosphere”, said Dr. Charles Tarnocai, Agriculture and Agri-Food Canada, Ottawa, and lead author.
So the fact that the permafrost is now permamelt becomes a concern truly second to none. More worrying still is that the melting is not the product of a single positive (or amplifying) feedback but, at a minimum, a tag team of three feedbacks each reinforcing each other while attacking from different angles: Land, Sea and Air. There is a comprehensive and devastating attack underway on the permafrost that would make General William Tecumseh Sherman proud.
From the Land:
A new article by Tracey Logan in New Scientist reports:
The fire that raged north of Alaska’s Brooks mountain range in 2007 left a 1000-square-kilometre scorched patch of earth – an area larger than the sum of all known fires on Alaska’s North Slope since 1950.
Now scientists studying the ecological impact of the fire report that the blaze dumped 1.3 million tonnes of carbon dioxide into the atmosphere – about the amount that Barbados puts out in a year. What’s more, at next week’s meeting of the Ecological Society of America in Albuquerque, New Mexico, two teams will warn that as climate change takes hold tundra fires across the Arctic will become more frequent.
The concern is two-fold:
1. It transforms the tundra, traditionally a carbon sink, into an carbon emitter.
2. More importantly it radically increases the ground’s solar absorption.
Pristine tundra takes up about 30 to 70 grams of carbon per square metre during the summer months, whereas the severely burned site lost about 40 to 120 grams per square metre. The team also found that the most severely burned terrain absorbed 71 per cent more solar radiation than normal…
The really big problem: The burnt tundra — a newly minted solar heat collector — is sitting on the permafrost.
“Along with the melting ice in the permafrost, you’re also exposing more old carbon that was stored in that freezer [as organic material] and is being allowed to decompose and reintroduce itself to the atmosphere.”
Helping drive the Tundra fires is the air assault.
From the Air:
The average surface air temperature warming in the arctic has been many times greater than Earth’s average warming. The warming is concentrated where it can likely do the most damage. (See posts NASA: Another brutally hot year for the Siberian Tundra and NOAA’s arctic report card shows stronger effects of warming in Greenland and permafrost.)
The NOAA 2008 report card notes a shockingly number:
Autumn temperatures are at a record 5º C above normal, due to the major loss of sea ice in recent years which allows more solar heating of the ocean. Winter and springtime temperatures remain relatively warm over the entire Arctic, in contrast to the 20th century and consistent with an emerging global warming influence.
As the excerpt states the feedbacks are reinforcing each other. On to the the sea attack.
From the Sea:
Permafrost threatened by rapid melt of Arctic sea ice – reported the American Geophysical Union in 2008.
The team finds that, during episodes of rapid sea-ice loss, the rate of Arctic land warming is 3.5 times greater than the average 21st century warming rates predicted in global climate models. While this warming is largest over the ocean, the simulations suggest that it can penetrate as far as 1500 kilometers (about 900 miles) inland. The simulations also indicate that the warming acceleration during such events is especially pronounced in autumn. The decade during which a rapid sea-ice loss event occurs could see autumn temperatures warm by as much as 5 degrees C (9 degrees F) along the Arctic coasts of Russia, Alaska, and Canada.
What’s to worry about? It’s not like we’ve been losing all that much sea ice – NOT. See also North Pole poised to be largely ice-free by 2020: “It’s like the Arctic is covered with an egg shell and the egg shell is now just cracking completely”.
The rapidly melting Arctic permafrost is now our biggest existential threat – as it was the Soviet ICBMs raining down from the Arctic circle we so feared growing up. And while we and the Soviets were restrained by self-interest, the hard-charging feedbacks have no such restraints. We must restrain the feedbacks. And as Joe says, the time to start is yesterday.
- NASA: Another brutally hot year for the Siberian Tundra
- NSIDC: Arctic is on thin ice – literally – and that means the “perma”frost is too
- Arctic Research Center: The underwater permafrost is melting and releasing methane
- Breaking News – Tundra 4: Permafrost loss linked to Arctic sea ice loss
- Tundra 3: Forests and fires foster feedbacks
- Tundra, Part 2: The point of no return
- The permafrost won’t be perma for long, Part 1