Thawing Permafrost a Significant Source of Carbon
15 June 2006
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| Circumarctic map of permafrost. Click to enlarge. Source: UNEP-GRIDA |
With global temperatures rising, the Arctic’s “permanently” frozen soil—permafrost—isn’t staying frozen. A type of soil contained deep within thawing permafrost—loess—may be releasing significant, and previously unaccounted for, amounts of carbon into the atmosphere, according to authors of a paper published this week in the journal Science.
Some have been warning about the danger of melting permafrost for a number of years. For example, Svein Tveitdal, managing director of GRID-Arendal in Norway, a United Nations Environment Program (UNEP) information center, warned of the potential in 2001:
Permafrost has acted as a carbon sink, locking away carbon and other greenhouse gases like methane, for thousands of year. But there is now evidence that this is no longer the case, and the permafrost in some areas is starting to give back its carbon. This could accelerate the greenhouse effect.
The just-published work by the scientists from Russia, the University of Florida, and the University of Alaska Fairbanks found that loess permafrost—extending more deeply into the permafrost layers and covering more than a million square kilometers in Siberia and Alaska—is a very large carbon reservoir with the potential to be a significant contributor of atmospheric carbon, yet one seldom incorporated into analyses of changes in global carbon reservoirs.
The unique aspect of the Siberian loess permafrost is that it is quite deep—20 to 40 meters—and has a surprisingly high carbon concentration at depth for a mineral soil. This paper explains the processes that led to the accumulation of large amounts of soil carbon and the processes that could lead to its return to the atmosphere.
—Terry Chapin, co-author from the Institute of Arctic Biology at UAF
People know about carbon in permafrost—it’s not a trivial amount. Normally, scientists look for carbon in the upper layers of permafrost where organic matter decomposes.
—Ted Schuur, co-author from the University of Florida
The largest carbon reservoir on Earth is the ocean, which scientists estimate holds about 40,000 gigatons (Gt); soils contain about 2,500 Gt and vegetation about 650 Gt. According to the authors, about 500 Gt of carbon are contained in the thaw-threatened loess, also called yedoma, of Siberia and Alaska.
By comparison, in 2003, total worldwide emissions of carbon from the combustion of fossil fuels was 6.8 Gt (25.1 Gt CO2), according to the US Energy Information Administration. Total 2003 worldwide emissions of carbon from the combustion of petroleum was 2.5 Gt (9.3 Gt CO2). The release of even a portion of an extra 500 Gt of carbon—equivalent in total to the release of 1.8 trillion tons of CO2—would, in other words, be a significant addition, even spread out over time.
I was surprised, because it is unusual to find major new large carbon stocks. We have spent more than five years discussing among ourselves all the details of the calculations, because initially I did not believe that the pool could be both so large and so decomposable (once thawed).
—Terry Chapin
Laboratory and field experiments by the scientists demonstrate that the organic matter in yedoma decomposes quickly when it is thawed and produces rates of carbon release similar to those of productive northern grassland soils.
Permafrost has been seldom incorporated into global carbon budgets in part because the “... size of the carbon pool was so poorly quantified ... and in part because global data bases for soils have been standardized to provide data only for the top meter of soil,” Chapin said.
If these rates continue as field observations suggest, most carbon in recently thawed yedoma will be released within a century—a striking contrast to the preservation of carbon for tens of thousands of years when frozen in permafrost.
Resources:
“Permafrost and the Global Carbon Budget”; Sergey A. Zimov, Edward A. G. Schuur, F. Stuart Chapin III; Science 16 June 2006: Vol. 312. no. 5780, pp. 1612 - 1613 DOI: 10.1126/science.1128908
Note that soil temperatures are more or less constant all year 'round several meters below the surface. Only the top layer currently melts during the short arctic summers, turning the tundra into impassable, infect-infested mud.
The polar regions will presumably experience a higher change in temperature than more temperate latitudes, simply because the atmospheric convection of heat concentrates in a smaller area there. Therefore, even mild global warming should have a noticeable effect on the average seasonal thaw depth (i.e. the thickness of the layer that alternately thaws and freezes) of the tundra. If the associated outgassing is irreversible in the short term, there is a positive feedback in the system, i.e. a potential runaway greenhouse gas scenario.
However, the greater the thaw depth, the thicker the thermal insulation layer on top of the remaining permafrost. Further from the pole, the topmost fraction of this layer may no longer freeze in winter. Nevertheless, it would take a fairly massive increase in average surface temperatures to push the permafrost boundary downward by e.g. one full meter. Of course, even a far more modest increase in the thaw depth could have serious consequences for the atmospheric CO2 concentration, given the sheer size of the Alaska and Siberia.
However, the above summary seems to imply that *all* of the carbon stored throughout the full thickness of the yedoma stratum might be released on a timescale that is relevant to the present global warming debate. I wonder if that is what the paper actually claims - the full text is not available here.
Posted by: Rafael Seidl | 15 June 2006 at 05:19 PM
If majority methane (CH4), then HOLY !*#@! Add that to higher sea levels, less sea ice, and consequently shoreline erosion and we could see a spike in warming/ climate change in the artic/subartic more in line with more extreme projections.
Note: Many artic Siberian coastal plains are not much higher than sea level presently. A small rise in sea level, coupled with erosion, may push coastlines miles inland, and up rivers long distances.
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http://www.whoi.edu/science/PO/arcticgroup/projects/sealevel.html
Posted by: allen zheng | 15 June 2006 at 06:10 PM
arctic/subarctic
Posted by: allen zheng | 15 June 2006 at 06:12 PM
allen z: Alaska and the much larger Canadian Artic is not as flat as you make it to be. It is NOT like Florida's wetlands. There are plenty of high lands and mountains and 'tundra' is not present everywhere. However, if the few million square kilometers of tundra melts, it will release huge amoung of methane gas and accellerate climate changes with much higher temperatures and significant rise in ocean level. Most of Florida, New Orleans and NY City area +++ would disappear under the sea.
Let's hope that we can reverse the current trend before it is too late. Unfortunately, we will not beleive it until it happens. Our children and grandchildren should invest in high lands.
Posted by: Harvey D. | 15 June 2006 at 07:42 PM
It was too late in 1970. And the perma frost is melting all the way through because its been slowly getting warmer in its entirety.
Posted by: wintermane | 15 June 2006 at 10:43 PM
With that amount of CO2 being released, it does not matter any more how far you live from the ocean.
That's Apocalypse-not-now-but-in-fifty-years.
Posted by: sram | 16 June 2006 at 07:03 AM
Seems that 'out-of-the box' solutions need developing.
For example, I understand that tree growth is contributing to lower duration freezes -- as shaded areas have no snow cover and warm faster, contributing to warming around them. Thus, clear cutting of trees in permafrost/such areas?
In terms of this, perhaps we should (must?) seek 'insulation' type paths toward reducing warming in these areas. The equivalent of white reflective roofs? (Note, my understanding is that if man would put white (reflective) roofs on all structures/worldwide, that there would be a notable reduction in warming ... )
Amid the terror on the implications, one question might be whether there are paths to ameliorate / reduce the warming & outgassing of this CO2. ... A thought ...
Posted by: Adam | 16 June 2006 at 08:15 AM
Harvey D.
It is not called Western Siberian Plain for nothing. Then you have the river deltas/mouths like the Ob, or the Lena. The topography of the Arctic continental shelf also extends itself onto land, with river lowlands and peninsulas not rising far from sea level. Furthermore, although there are uplands plateaus and mountains, large chunks of Siberia are not above 50 meters. While not as low as 50 ft. max for much of Florida, look at topographical maps of the Arctic and you could superimpose Florida (or many Floridas) on those pieces of coastline/river flood plains near deltas/mouths.
Posted by: allen zheng | 16 June 2006 at 08:34 AM
Adam,
Interesting, make all sun facing sides of a structure white/reflective. A world of white or silver metallic or gold buildings. I have heard of giving Kilimanjaro white plastic sheets for reflective purposes.
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____Another would be hot water tubes running under photovotaic arrays mounted on roofs/sunfacing facades (southern in northern hemisphere and vice versa). If percipitation allows, green roofs may do the job in urban environs.
Posted by: allen zheng | 16 June 2006 at 08:43 AM
Allen Z: The Russian side may have more plains and low lands. The North American side, beside river deltas, is rather mountainous. I crashed at 8000+ feet at 70+ degrees north in my younger days.
Is it confirmed that methane emission is a lot worse than C02 emission with regards to climate change? If it is the case, perma frost melting may have a very significant effect before 2050.
Since we are in the middle (or somewhere near the crest) of a long term natural warming cycle and are not very willing to reduce man-made GHG, we may have to accept the dire consequences. Rebuilding New Orleans City may not be an economical decision. Moving it to higher lands (200+ feet) would be a better investment.
Posted by: Harvey D. | 16 June 2006 at 10:30 AM
On the plus side: a great time to get in on the basement waterproofing business.
Posted by: Dursun | 16 June 2006 at 11:17 AM
Because of a 500 plus year climate cycle we are indeed right smack dab in a natural climate change on top of what we are doing. That change is enough to cause the offgassing.
Many eople forget it isnt the last 10 years thats important climate wise it was the last 10000 years and all the farming and city building and what not. The last 1--30 years was just the ta da! to a long show.
Posted by: wintermane | 16 June 2006 at 11:43 AM
Harvey D. -
the effects of different greenhouse gases are compared using their global warming potential, relative to the same mass of CO2. The GWP value depends on the time horizon chosen, as different gases are broken down at different rates. Methane has a GWP of 21 over 100 years, R134a (modern A/C fluid) a GWP of 1300.
http://en.wikipedia.org/wiki/Global_warming_potential
http://www.epa.gov/nonco2/econ-inv/table.html
Note also that an estimated 150 billion m^3 of natural gas is either flared or simply vented in the course of oil production, either for safety or because it is too far from any viable market. This is equivalent to the total gas consumption of Germany and France combined. The World Bank is working with a number of countries to mitigate the problem.
http://web.worldbank.org/WBSITE/EXTERNAL/TOPICS/EXTOGMC/EXTGGFR/0,,menuPK:578075~pagePK:64168427~piPK:64168435~theSitePK:578069,00.html
Posted by: Rafael Seidl | 16 June 2006 at 05:39 PM
Turning flare gas into methanol would be a better use of that wasted resource. But again, it comes under the heading of not "cost effective". When we start doing what is right and not just what is merely the most profitable, we might start to get on a better track to a sustainable future.
Posted by: sjc | 17 June 2006 at 06:53 AM
Sjc -
the most common flare gas reduction stategy is to use it for on-site electricity generation:
http://www.epa.gov/gasstar/workshops/houston-oct2005/frantz.pdf
At large flare gas sites in remote locations, it would indeed be possible to produce methanol and use that directly as a motor fuel. It has a high octane number and rapid combustion profile. However, its high neurotoxicity, colorless flame and low energy density have prevented its application beyond certain high-performance race cars.
The methanol can be turned into DME or gasoline using the MTG process. Methanex operates a plant in New Zealand, apparently about 90% of the cost is the methanol feedstock. Note that the methanol precursor can also be produced quite easily from biomass (its other name is wood alcohol).
http://chemelab.ucsd.edu/methanol/indexMTG/main.html
Posted by: Rafael Seidl | 17 June 2006 at 09:33 AM
Another would be to use the associated gas (gas that comes out with the crude oil) for oil/petroleum operations (gas fired rotary engine pump, electric generation/heat cogeneration/ CO2 generation for oil recover/enhanced recovery/ sequestation). You could also strip off the H2 and use it for chemicals/petro fraction upgrades. Afterwards, burn the C to CO2 for heat for purposes described above (or for other processes needing C). Other gases could be captured and used, like Helium.
Posted by: allen zheng | 17 June 2006 at 12:19 PM
Allen -
afaik, there is typically almost no free carbon nor free H2 in crude oil. I'm not sure what you are referring to.
Any electricity generated from flare gas on-site is used first and foremost on-site to power various production equipment. Where possible, the bulk of the gas is shipped to market or else re-injected into the reservoir to reduce viscosity.
The World Bank has identified Russia, Nigeria, the Equatorial Guinea basin and Iran as the most prolific flarers (10-15 billon m^3 each per year), but Algeria, Iraq and others also flare off quite a bit.
One hope is to expand the world's LNG infrastructure so this gas can be brought to market. Other option include GTL plants (floating offshore in Nigeria's case) and, perhaps, the production of carbon fibers for use in lightweight automotive chassis. Energy inputs are a key cost factor in carbon fiber production.
CF composites would reduce demand for fuel and CO2 emissions. They are currently only used for chassis development prototypes, race cars and the roof structure of the BW X3. However, CF deployment on a large scale would only be feasible if the fibers were cheap enough to burn when the vehicles are scrapped, since recovery processes tend to produce shorter, less effective fibers. The EU requires all LDVs to be recycled.
Posted by: Rafael Seidl | 18 June 2006 at 04:54 AM
Cont. from previous:
Instead of flaring the gas. US also is worried of running short of Helium. The gas has uses on the horizon, like in some 4th gen nuke plats, and high altitude (70,000-100,000 ft and above the jet stream) semi-stationary solar powered surveilance systems.
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____Iraq needs to move off of fuel oil and onto their cheap excess natural gas once it stabilizes. It will need to build the plants to process/use the gas however. On the other hand, it may export it to Turkey, and maybe beyond (EU; LNG->world). In the long term, they have lots of desert in the west, south west of the Euphrates, as well as extreme east with parts facing Iran and gaps between the rivers. It may placate the Sunnis with money from electricity/hydrogen/algae fuel (grown with water saving methods, and from waste water treatment plants) produced there. Long term, and if the insurgency is snuffed out (2-7yrs).
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____ You may ask "what would an OPEC country be doing investing in alternative energy?...Would this not be self defeating?". The answers are that:
a) many of the oil fields were damaged under 30 yrs of Saddam, especially the period from the Iran Iraq war in 1980, up to 2003. Injection of heavy oil and other practices may have pernamently reeduced the amount of oil that some of the largest fields can produce. New exploration may yield more oil, but may muddle the oil revenue sharing question again. Long term oil will become scarcer and harder to extract. Expensive secondary and tertiary methods would be needed to extract from salvageable fields.
b) Iraqis need waste water treatment to prevent the degregation (and futher degregation) of their prized rivers. Water is gold, it is life in the Middle East.
c) Iraq needs electricity! Alternatives give them the some degree of future proofing as they build from scratch in many places.
d) The Marsh Arabs and the few Iraqi ports may not like being inundated by global warming. Investing in alternatives may give a way for Iraq to stay together politically through interdependence and cooperation. Using electricity and heat may be used for desalination if the river dry up due to shifting climate patterns may be one example.
e) Excaping the oil curse will be hard, and this may help Iraq develope a sector (along with agriculture, precison manufacturing, biotech, chemicals; building/making those weapons has got to amount to something) to propel them into the developed world.
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