Kelp Farming and Ice Dyking

Aaron Franklin

Kelp farming and ice dyking for habitat enhancement 

and carbon-negative fuels and chemical production.

By Aaron Franklin

A purpose-built craft like this Ground effect plane / hovercraft triphibian concept could be ideal.

The laterally-rigid sideskirts with vertically-flexible surface-contouring ski bottoms would allow transitions between air, water, ice, snow, earth surfaces of all types and the waterscoop tail could directly hose the water onto the ice with foil effect to counter lateral reaction thrust. Snow making, firefighting, and ecology seeding also in its functionality.

At pumping of 10tons per second, 50m x 100m/s = 5000sqm, 10000kg/5000sqm = 2 kg per sqm per pass. About 2mm per pass.

If we assume conditions that will allow 2 mm to freeze in 30 seconds. then 4mm per minute = 240mm per hour = 5760mm (near 6m thick) per day could be made of 50m wide by 100m/s x 30s = 3km long of icedyke by a mobile spray vehicle at 100m/s.

3000m x 6m x 50m = 900 000 tons per day of ice making.

A fleet of 50 working for 100 days therefore could make 5000 x 900 000 = 45 000 000 000 tons or near 5 cubic kilometers of ice. 

If we are looking at an average needed to ground them of say 30m thick, then 50m wide is cross section area of 1500 sqm.

5 000 000 000 cubic m / 1500 sqm = 3.33333 million meters or 3333 km.

A ball park figure of 1000kw vehicle power would seem adequate to do this.

Very likely a rope mesh reinforcement would need to be floated on the water and anchored in place to hold together the dyke that has been formed. Doing this work in polynyas seems the best way, then towing into position of sections to be anchored and further thickened.

If 100 such vehicles were used you've got near seven thousand km of icedyke which could be enough for such a layout as this:

Kelp farming, by Aaron Franklin, on background image by Shakhova et al., 2010. 

For methane plume hotspots to the surface, hexagonal tiles would need to be formed and towed into place, if they are too rich for ice to form inside the rings in situ.

Stationary pumping systems might have to high costs per area in most places with limits to small volumes per pump due to area feasible to distribute the water to and ice layup rates. Though in saying this, high cost is often seen as a benefit for commercial interests. They can make more money doing it the hard way.

The purposes of kelp farming in the less methane emissive areas is as follows:

• Biomass for biofuels and biochemicals of around 500 ton per hectare per year can be harvested.
• The growing kelp oxygenates the water to support consumption of methane and river in-flux of organic carbon.
• The artificial kelp forests provide habitat and food for a diverse and rich ecology with fisheries and abalone/ mussel/ crabs / lobster etc farming potential
• Unlike micro algae, the kelp biomass is easily harvested, so it would not rot and cause oxygen depletion of the water at the end of summer.
• Sedimentation rates and water clarity are vastly improved by the kelp forests, thereby improving albedo and enhancing natural carbon burial in sediments.
• Simple and low cost infrastructure only is neccessary to process the kelp locally into liquids for low transport costs to refineries for further upgrading.
• It would be easy to use the CO2 from an initial biomass pyrolysis to convert methane collected nearby to methanol for easy low cost transportation.

Combining these systems would allow zero carbon emission liquid fuels via the energy component of the fossil methane and biomass being used as hydrogen and the carbon turned into biochar and high performance bioglues and recyclable polymers, allowing further long-term carbon sequestration by wood, biofibre, etc., and component for construction materials, also replacing high carbon-emission steel, concrete etc.

Save the Arctic

by Renaud de Richter

Links

- This idea was proposed by Denis Bonnelle,
'Solar Chimney, water spraying Energy Tower, and linked renewable energy conversion devices: presentation, criticism and proposals', p120-125.
PhD thesis 9 July 2004, university Claude Bernard, Lyon, France, registration n°129-2004.
http://data.solar-tower.org.uk/thesis/2004-Denis-BONNELLE_Solar-chimneys_Energy-towers_etc.pdf

- For more ideas, see: 

Fighting global warming by climate engineering: Is the Earth radiation management and the solar radiation management any option for fighting climate change?
By Tingzhen Ming, Renaud de_Richter, Wei Liu and Sylvain Caillol
http://www.sciencedirect.com/science/article/pii/S1364032113008460

Ocean Tunnels

Ocean tunnels are proposed by Patrick McNulty as a way to combat global warming. Many of these tunnels, lined up across the Gulf Stream and the Kuroshio Current, could supply large quantities of clean energy to the North American East Coast and to East Asia.

Such tunnels can supply energy continuously, i.e. 24 hours a day, all year, making them suitable to supply base load energy as currently generated by coal-fired power plants and nuclear power plants. 

Ocean tunnels thus hold the potential to supply huge amounts of clean energy and facilitate a rapid move to a sustainable economy, as part of the comprehensive and effective action needed to combat climate change. This is pictured in the image below under part 1. 

Comprehensive and effective action is discussed at the Climate Plan blog

Ocean Tunnels can be combined with Ocean thermal energy conversion (OTEC) methods that use the temperature difference between cooler deeper parts of the ocean and warmer surface waters to run a heat engine to produce energy. Once such a system is in place, it has access to both deeper parts of the ocean and to surface waters, while generating a lot of energy. Such a system can also be used to pull up sunken nutrients from the depth of the ocean and put them out at surface level to fertilize the waters there, while the colder water that is the output of OTEC will float down, taking along newly-grown plankton to the ocean depths before it can revert to CO2, as described in the earlier post Using the Oceans to Remove CO2 from the Atmosphere.

Tunnels could regulate temperatures in the Arctic in a number of ways. The clean electricity they generate can replace ways polluting energy that warms up the Arctic. The clean energy tunnels generate can also be used in projects that help reduce temperatures in the Arctic. Furthermore, the turbines in tunnels can reduce the flow of ocean currents somewhat, thus reducing the flow of warm water into the Arctic.

Additionally, tunnels also hold the potential to divert warm water elsewhere and to move colder water into places that could otherwise get too warm, i.e. part 2. (Heat management) of the above action plan, more specifically management of water temperature.

Tunnels could be shaped to guide the flow of water into a specific direction, which could divert some of the water that is currently going into North Atlantic Current towards the Arctic Ocean down a southwards course along the Canary Current along the coast of West Africa.

Thus, tunnels could both produce energy to pump water elsewhere, or to pump water onto the sea ice and glaciers, to thicken the ice, or to pump sea water up into the air to spray it around and create clouds. The energy could be used in projects to help reduce temperatures in the Arctic. Additionally, tunnels could also be shaped in ways to guide water, which works even when no energy is generated. Tunnels is a concept with many applications and testing and further studies will show which applications are attractive.

A comprehensive action plan will need to consider a wide range of action. A warming Arctic results in changes to the Jet Stream, in turn making that more extreme weather can be expected, as illustrated by the video below, by Paul Beckwith. 

In July 2013, water off the coast of North America reached 'Record Warmest' temperatures and proceeded to travel to the Arctic Ocean, where it is still warming up the seabed, resulting in huge emissions of methane from the Arctic Ocean's seafloor.

NOAA: part of the Atlantic Ocean off the coast of North America reached record warmest temperatures in July 2013

Diversion of ocean currents could reduce warming of the waters in the Arctic. As the image below shows, warm water is carried by the Gulf Stream all the way into the Arctic Ocean.

Warming up of the waters in the Arctic is threatening to cause release of huge quantities of methane that is held in sediments under the seabed, as discussed in the post Quantifying Arctic Methane.


References

- Climate change: Solutions to a big problem

http://arctic-news.blogspot.com/2013/05/climate-change-solutions-to-a-big-problem.html

- Arctic Methane Release and Rapid Temperature Rise are interlinked

http://arctic-news.blogspot.com/2013/11/arctic-methane-release-and-rapid-temperature-rise-are-interlinked.html

- Causes of high methane levels over Arctic Ocean

http://arctic-news.blogspot.com/2013/10/causes-of-high-methane-levels-over-arctic-ocean.html

- Quantifying Arctic Methane

http://arctic-news.blogspot.com/2013/11/quantifying-arctic-methane.html

How to avoid mass-scale death, destruction and extinction

Climate change threatens to develops in four ways:

1. Global warming
2. Accelerated warming in the Arctic
3. Runaway global warming
4. Extinction

Warming accelerates in the Arctic due to a number of feedbacks, ten of which are depicted in the Diagram of Doom.

One of these feedbacks, methane releases from the Arctic seabed, constitutes a point-of-no-return, in that this threatens to trigger further releases in a vicious cycle that will escalate into runaway global warming. The combined impact of land degradation, storms and heatwaves will then cause crop and vegetation loss at unprecedented scale, resulting in mass death, destruction and extinction.

High food prices have been around for a few years, as illustrated by the FAO Food Price Index below (see interactive version of this image).

The FAO, in its recent Cereal Supply and Demand Brief, explains that we can expect prices to rise, as illustrated below.

The Economic Research Service of the U.S. Department of Agriculture mentions, in its Food Price Outlook, 2012-2013, that the "drought has affected prices for corn and soybeans as well as other field crops which should, in turn, drive up retail food prices".

Global food supply is under stress as extreme weather becomes the new norm. Farmers may be inclined to respond to drought by overusing ground water, or by slashing and burning forest, in efforts to create more farmland. Such practices do not resolve the problems; instead, they tend to exacerbate the problems over time, making things progressively worse.

The diagram below shows that there are many climatological feedbacks (ten of which are named) that make climate change worse. At the top, the diagram pictures vicious cycles that are responses by farmers that can add to make the situation even worse. Without effective action, the prospect is that climate change and crop failure combine to cause mass death and destruction, with extinction becoming the fourth development of global warming.

How can we avoid that such a scenario will eventuate? Obviously, once we are in the fourth development, i.e. mass-scale famine and extintion, it will be too late for action. Similarly, if the world moves into the third development, i.e. runaway global warming, it will be hard, if not impossible to reverse such a development. Even if we act now, it will be hard to reverse the second development, i.e. accelerated warming in the Arctic.

The most effective action will target causes rather than symptoms of these developments.

Part 1. Since emissions are the cause of global warming, dramatic cuts in emissions should be included in the first part of the responses. In addition, action is needed to remove excess carbon dioxide from the atmosphere and oceans. Storing the carbon in the soil will also improve soil quality, as indicated by the long green arrow on the left.

Part 2. Solar radiation management is needed to cool the Arctic.

Part 3. Methane management and further action is needed, e.g. to avoid that methane levels will rise further in the Arctic, which threatens to trigger further releases and escalate into runaway global warming. Measures to reduce methane can also benefit soil quality worldwide, as indicated by the long green arrow on the right.

Thus, the proposed action tackles the prospect of mass death and extinction by increasing soil fertility, as illustrated by the image below.

Depicted at the bottom of the image are the most effective policies to accomplish the goals set out in the proposed 3-part plan of action, i.e. feebates, preferably implemented locally. Cost associated with solar radiation management is relatively small, so relatively small fees, e.g. on commercial international flights could raise the necessary funding.

A Comprehensive Plan of Action on Climate Change

Threat to global food supply makes comprehensive action imperative

Climate change is strongly affecting the Arctic and the resulting changes to the polar vortex and jet stream are in turn contributing to extreme weather in many places, followed by crop loss at a huge scale.

The U.N. Food and Agriculture Organization (FAO) said in a September 6, 2012, forecast that continued deterioration of cereal crop prospects over the past two months, due to unfavourable weather conditions in a number of major producing regions, has led to a sharp cut in FAO’s world production forecast since the previous report in July.

The bad news continues: Based on the latest indications, global cereal production would not be sufficient to cover fully the expected utilization in the 2012/13 marketing season, pointing to a larger drawdown of global cereal stocks than earlier anticipated. Among the major cereals, maize and wheat were the most affected by the worsening of weather conditions.

The image below is interactive at the original post and shows the FAO Food Price Index (Cereals), up to and including August 2012.

from: Threat to global food supply makes comprehensive action imperative

Apart from crop yield, extreme weather is also affecting soils in various ways. Sustained drought can cause soils to lose much of their vegetation, making them more exposed to erosion by wind, while the occasional storms, flooding and torrential rain further contribute to erosion. Higher areas, such as hills, will be particularly vulnerable, but even in valleys a lack of trees and excessive irrigation can cause the water table to rise, bringing salt to the surface.

Fish are also under threat, in part due to ocean acidification. Of the carbon dioxide we're releasing into the atmosphere, about a third is (still) being absorbed by the oceans. Dr. Richard Feely, from NOAA’s Pacific Marine Environmental Laboratory, explains that this has caused, over the last 200 years or so, about a 30% increase in the overall acidity of the oceans. This affects species that depend on a shell to survive. Studies by Baumann (2011) and Frommel (2011) indicate further that fish, in their egg and larval life stages, are seriously threatened by ocean acidification. This, in addition to warming seawater, overfishing, pollution and eutrification (dead zones), causes fish to lose habitat and is threatening major fish stock collapse.

Without action, this situation can only be expected to deteriorate further, while ocean acidification is irreversible on timescales of at least tens of thousands of years. This means that, to save many marine species from extinction, geoengineering must be accepted as an essential part of the much-needed comprehensive plan of action.

Similarly, Arctic waters will continue to be exposed to warm water, causing further sea ice decline unless comprehensive action is taken that includes geoengineering methods to cool the Arctic. The threat that huge amounts of methane will be released from the warming Arctic seabed makes it imperative to prepare geo-engineering methods to respond to this threat and be ready for rapid deployment soon.

How to avert an intensifying food crisis

As extreme weather intensifies, the food crisis intensifies. Storms and floods do damage to crops and cause erosion of fertile topsoil, in turn causing further crop loss. Similarly, heatwaves, storms and wildfires do damage to crops and cause topsoil to be blown away, thus also causing erosion and further crop loss. Furthermore, they cause soot, dust and volitale organic compounds to settle on snow and ice, causing albdeo loss and further decline of snow and ice cover.

Extreme weather intensifies as the Arctic warms and the polar vortex and jet stream weaken, which is fueled by accelerated warming in the Arctic. There are at least ten feedbacks that contribute to further acceleration of warming in the Arctic and without action the situation looks set to spiral away into runaway global warming, as illustrated by the image below.

Diagram of Doom, with Comprehensive Plan of Action added  (credit: Sam Carana, October 9, 2012)

To avert an intensifying global food crisis, a comprehensive plan of action is needed, as also indicated on the image. Such a plan should be comprehensive and consider action in the Arctic such as wetland management, ice thickening and methane management (methane removal through decomposition, capture and possibly extraction).

A Comprehensive Plan of Action on Climate Change

A Comprehensive Plan of Action on Climate Change needs to include policies to achieve a sustainable economy, as well as adaptation policies.

Such a comprehensive plan is best endorsed globally, e.g. through an international agreement building on the Kyoto Protocol and the Montreal Accord. At the same time, the specific policies are best decided and implemented locally, e.g. by insisting that each nation reduces its CO2 emissions by a set annual percentage, and additionally removes a set annual amount of CO2 from the atmosphere and the oceans, followed by sequestration, proportionally to its current emissions.

Policy goals are most effectively achieved when policies are implemented locally and independently, with separate policies each addressing a specific shift that is needed in order to reach agreed targets. Each nation can work out what policies best fit their circumstances, as long as they each independently achieve agreed targets.

Cuts in CO2 emissions of 80% by 2020 can be achieved by implementing local policies focusing on specific sectors (such as energy production, transport, land use, waste, forestry, buildings, etc).

As an example, each nation could add fees on jetfuel. Where an airplane lands that comes from a nation that has failed to add sufficient fees, the nation where the airplane lands could impose supplementary fees and use the revenues to support methods that capture CO2 directly from ambient air. Such supplementary fees should be allowed to be imposed under international trade rules.

Some policies will need to continue beyond 2020, in order to bring down levels of greenhouse gases in the atmosphere to their pre-industrial levels this century, i.e. getting CO2 in the atmosphere back to 280ppm, CH4 back to 700ppb and N2O back to 270ppb. Policies can be very effective when focusing on local sectors such as agriculture and buildings, while also supporting geo-engineering methods such as biochar, enhanced weathering and direct capture of carbon from ambient air.

In addition to such policies to achieve a sustainable economy and adaptation policies, further geo-engineering methods will be needed to avoid runaway warming, as indicated in the blue area of the image below.

Arctic Methane Management

At the original post, some of the areas in these images can be clicked on, for examples or more background. The box for Additional Arctic Methane Management on above image is further worked out in the image below, which highlights the need for geo-engineering methods that focus on methane, a component of the plan that needs to be given far more attention. Again, support for such methods could be agreed to proportionally to each nation's current emissions.

Arctic - red alert!

January 2012 shows record levels of methane in the Arctic

In January 2012, methane levels in the Arctic reached levels of 1870 ppb. 

Particularly worrying is that, in the past, methane concentrations have fluctuated up and down in line with the seasons. Over the past seven months, however, methane has shown steady growth in the Arctic. Such a long continuous period of growth is unprecedented, the more so as it takes place in winter, when vegetation growth and algae bloom is minimal. The most obvious conclusion is that the methane is venting from hydrates. 

Extract from: The need for geo-engioneering

How much time is there left to act?

How much time is there left to act, before methane hydrate releases will lead to human extinction? 

by Malcolm Light, edited by Sam Carana

 

Figure 1 below looks at the temperature impact of abrupt methane releases, as measured in 2010 in Svalbard (above image). Such emissions are typically triggered by disruption of the integrity of the hydrates holding the methane.

As the red line on the graph indicates, these emissions would raise local temperatures significantly, in a matter of months, since methane has a strong greenhouse effect.

At the time, the rapid increase in methane levels alarmed scientists around the world, but NASA now regards these releases merely as a local peak event that had little impact on overall global temperatures. Even so, the Svalbard event is indicative of the local temperature impact of such emissions.

The IPCC estimates the temperature change at 2090-2099 (relative to 1980-1999) at between 1.8°C (likely range: 1.1°C to 2.9°C) and 4.0°C (likely range: 2.4°C to 6.4°C), depending on the chosen scenario.

There are several ways to project how much temperatures will rise in future. The chart below shows the global temperature rise from 1980 to 2011, using the most recent NASA data. Clearly, a simple linear extension of this trend would not suffice, as it would ignore the many feedback effects accelerating the rise.

The worst-case IPCC scenario projects a mean temperature rise that would take average global temperature beyond 20 degrees Celsius this century, an obviously catastrophic scenario. Yet, the IPCC scenarios fail to include the many feedbacks that accelerate temperature rises, such as large abrupt releases from methane hydrates. In fact, the IPCC miserably failed to warn about the dramatic loss of Arctic sea ice, as pictured on the chart below, by Wipneus based on PIOMAS data.

Mid-point IPCC projections have been incorporated in Figure 2 below for reference. The diagram also incorporates the warming impact of large methane releases, triggered by a scenario based on the data from Svalbard and by the impact of increased seismic activity in the Arctic. 

Above updated global warming extinction diagram was produced using new information from the ice cap melting curve and the measured Svalbard methane concentrations (NOAA 2011a). 

While the gradients were calculated in a different way, taking account of existing Arctic temperatures, the result is almost identical to the earlier version. Furthermore, methane would only require to have a global warming potential of 43.5 over 50 years duration (Figure 2, duration from Carana 2011g) to achieve this high temperature increase in the Arctic.  The Arctic ice cap heating curves lag behind the expected Arctic atmospheric temperature curves by some 10 to 20 years over the defined extinction period which is probably a result of the extra energy needed for  the latent heat of melting of ice as the permafrost, Greenland and Antarctic ice caps melt away (Figure 2).

It is perfectly clear from the graphs that the methane build up in the Arctic is mainly a result of increasing earthquake activity along the Gakkel Ridge caused by global warming induced worldwide expansion of the Earth’s crust due to the carbon dioxide buildup in the atmosphere which is enhanced by the heating up of the Arctic ocean due to the high global warming potential of the methane (Light 2011). This close relationship between the Gakkel Ridge earthquake activity, the destabilisation of the Arctic methane hydrates and the NASA GISS surface temperature anomalies has already been clearly demonstrated (Carana, 2011b; Light 2011).

If I was a medical doctor I would say that the patient has a terminal illness and is expected to die of an extreme fever between 2038 and 2050. There are three actions that have to be taken immediately by world governments, if there is any faint hope of preventing the final excruciating stages of death the human race will be forced to live through as we are all boiled like lobsters.

1. Developed (and some developing) countries must cut back their carbon dioxide emissions by a very large percentage (50% to 90%) by 2020 to immediately precipitate a cooling of the Earth and its crust. If this is not done the earthquake frequency and methane emissions in the Arctic will continue to  grow exponentially leading to our inexorable demise in 2038 to 2050. 
    
2. Geoengineering must be used immediately as a cooling method in the Arctic to counteract the effects of the methane buildup in the short term. However, these methods will lead to further pollution of the atmosphere in the long term and will not solve the earthquake induced  Arctic methane buildup which is going to lead to our annihilation. 
    
3. The United States and Russia must immediately develop a net of powerful radio beam frequency transmission stations around the Arctic using the critical 13.56 MHZ  beat frequency to break down the methane in the stratosphere and troposphere to nanodiamonds and hydrogen (Light 2011a) . Besides the elimination of the high global warming potential methane, the nanodiamonds may form seeds for light reflecting noctilucent clouds in the stratosphere and a light coloured energy reflecting layer when brought down to the Earth by snow and rain (Light 2011a). HAARP transmission systems are able to electronically vibrate the strong ionospheric electric current that feeds down into the polar areas and are thus the least evasive method of  directly eliminating the buildup of methane in those critical regions (Light 2011a).

References

IPCC Fourth Assessment Report on Climate Change 2007 - temperature rise projections
ipcc.ch/publications_and_data/ar4/wg1/en/spmsspm-projections-of.html

NASA global temperature data
data.giss.nasa.gov/gistemp/tabledata_v3/GLB.Ts.txt

Arctic Sea Ice yearly minimum volume, with trendline added by Wipneus, based on data by
Polar Science Center | Applied Physics Laboratory | University of Washington (2011) http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/

Carana, S. (2011b), Light M.P.R. and Carana, S. (2011c)
Methane linked to seismic activity in the Arctic
arctic-news.blogspot.com/p/seismic-activity.html

Light M.P.R. (2011), Edited by Sam Carana
Use of beamed interfering radio frequency transmissions to decompose Arctic atmospheric methane clouds
arctic-news.blogspot.com/p/decomposing-atmospheric-methane.html

Carana, S. (2011g)
Runaway Global Warming
geo-engineering.blogspot.com/2011/04/runaway-global-warming.html

Hansen, J.E. (2011)
GISS Surface Temperature Analysis. NASA. Goddard Institute for Space Physics
data.giss.nasa.gov/cgibin/gistemp/do_nmap.py?year_last=2011&month_last=08&sat=4&sst=1&type=anoms&mean_gen=02&year1=2009&year2=2009&base1=1951&base2=1980&radius=1200&pol=pol

IPPC (2007)
Fourth Assessment Report on Climate Change 2007. FAO 3.1, Figure 1, WG1, Chapter 3, p. 253.
blogs.ei.colombia.edu/wp-content/uploads/2010/12/graph-2-600X422.jpg

Light M.P.R. (2011)
Global Warming
globalwarmingmlight.blogspot.com

Masters. J. (2009)
Top Climate Story of 2008
www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1177

NOAA (2011a), generated ESRL/GMO – 2010, November 08, 11:12 am
Huge sudden atmospheric methane spike Arctic Svalbard (north of Norway)
The need for geo-engineering

NOAA (2011b), generated ESRL/GMO – 2011, December 14, 17:21 pm
Huge sudden methane spike recorded at Barrow (BRW), Alaska, United States.
The need for geo-engineering

The potential for methane releases in the Arctic to cause runaway global warming

What are the chances of abrupt releases of, say, 1 Gt of methane in the Arctic? What would be the impact of such a release?

By Sam Carana, December 20, 2011, updated January 10, 2012

How much methane is there in the Arctic?

An often-used figure in estimates of the size of permafrost stores is 1672 Gt (or Pg, or billion tonnes) of Carbon. This figure relates to organic carbon and refers to terrestrial permafrost stores. (1)

This figure was recently updated to 1700 Gt of carbon, projected to result in emissions of 30 - 63 Gt of Carbon by 2040, reaching 232 - 380 Gt by 2100 and 549 - 865 Gt by 2300. These figures are carbon dioxide equivalents, combining the effect of carbon released both as carbon dioxide (97.3%) and as methane (2.7%), with almost half the effect likely to be from methane. (2)

In addition to these terrestrial stores, there is methane in the oceans and in sediments below the seafloor. There are methane hydrates and there is methane in the form of free gas. Hydrates contain primarily methane and exist within marine sediments particularly in the continental margins and within relic subsea permafrost of the Arctic margins. (3)

Hunter and Haywood estimate that globally between 4700 and 5030 Pg (Gt) of Carbon is locked up within subsea hydrate within the continental margins. This does not include subsea permafrost-hosted hydrates and so those of the shallow Arctic margin (<~300m) were not considered. (3)

Shakhova et al. estimate the accumulated methane potential for the Eastern Siberian Arctic Shelf (ESAS, rectangle on image right) alone as follows:

- organic carbon in permafrost of about 500 Gt;
- about 1000 Gt in hydrate deposits; and
- about 700 Gt in free gas beneath the gas hydrate stability zone. (4)  

The East Siberian Arctic Shelf covers about 25% of the Arctic Shelf (3) and additional stores are present in submarine areas elsewhere at high latitudes. Importantly, the hydrate and free gas stores contain virtually 100%  methane, as opposed to the organic carbon which the above study (2) estimates will produce emissions in the ratio of 97.3% carbon dioxide and only 2.7% methane when decomposing.

How stable is this methane?

The sensitivity of gas hydrate stability to changes in local pressure-temperature conditions and their existence beneath relatively shallow marine environments mean that submarine hydrates are vulnerable to changes in bottom water conditions (i.e. changes in sea level and bottom water temperatures). Following dissociation of hydrates, sediments can become unconsolidated, and structural failure of the sediment column has the potential to trigger submarine landslides and further breakdown of hydrate. The potential geohazard presented to coastal regions by tsunami is obvious. (3)

Further shrinking of the Arctic ice-cap results in more open water, which not only absorbs more heat, but which also results in more clouds, increasing the potential for storms that can cause damage to the seafloor in coastal areas such as the East Siberian Arctic Shelf (ESAS, rectangle on image left), where the water is on average only 45 m deep. (5)

Much of the methane released from submarine stores is still broken down by bacteria before reaching the atmosphere. Over time, however, depletion of oxygen and trace elements required for bacteria to break down methane will cause more and more methane to rise to the surface unaffected. (6)

There are only a handful of locations in the Arctic where (flask) samples are taken to monitor the methane. Recently, two of these locations showed ominous levels of methane in the atmosphere (images below). 

The danger is that large abrupt releases will overwhelm the system, not only causing much of the methane to reach the atmosphere unaffected, but also extending the lifetime of the methane in the atmosphere, due to hydroxyl depletion in the atmosphere.

Shakhova et al. consider release of up to 50 Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time. (7)

What would be the impact of methane releases from hydrates in the Arctic? 

If an amount of, say, 1 Gt of methane from hydrates in the Arctic would abruptly enter the atmosphere, what would be the impact? 

Methane's global warming potential (GWP) depends on many variables, such as methane's lifetime, which changes with the size of emissions and the location of emissions (hydroxyl depletion already is a big problem in the Arctic atmosphere), the wind, the time of year (when it's winter, there can be little or no sunshine in the Arctic, so there's less greenhouse effect), etc. One of the variables is the indirect effect of large emissions and what's often overlooked is that large emissions will trigger further emissions of methane, thus further extending the lifetime of both the new and the earlier-emitted methane, which can make the methane persist locally for decades.

The IPCC gives methane a lifetime of 12 years, and a GWP of 25 over 100 years and 72 over 20 years. (8)

Thus, applying a GWP of 25 times carbon dioxide would give 1 Gt of methane a greenhouse effect equivalent to 25 Pg of carbon dioxide over 100 years. Applying a GWP of 72 times carbon dioxide would give 1 Gt of methane a greenhouse effect equivalent to 72 Pg of carbon dioxide over 20 years.

By comparison, atmospheric carbon dioxide levels rose from 288 ppmv in 1850 to 369.5 ppmv in 2000, for an increase of 81.5 ppmv, or 174 Pg C. (9)

Note that this 174 Pg C was released over a period of 150 years, allowing sinks time to absorb part of the burden. Note also that, as emissions continue to rise, some sinks may turn into net emitters, if they haven't already done so.

The image on the left shows the impact of 1 Gt of methane, compared with annual fluxes of carbon dioxide based on the NOAA carbon tracker. (10) 

Fossil fuel and fires have been adding an annual flux of just under 10 Pg C since 2000 and a good part of this is still being absorbed by land and ocean sinks. 

In other words, the total burden of all carbon dioxide emitted by people since the start of the industrial revolution has been partly mitigated by sinks, since it was released over a long period of time.

Furthermore, the carbon dioxide was emitted (and partly absorbed) all over the globe, whereas methane from such abrupt releases in the Arctic would - at least initially - be concentrated in a relatively small area, and likely cause oxygen depletion in the water and hydroxyl depletion in the atmosphere, while triggering further releases from hydrates in the Arctic.

This makes it appropriate to expect a high initial impact from an abrupt 1 Gt methane release, which will also extend methane's lifetime. Applying a GWP of 100 times carbon dioxide would give 1 Gt of methane an immediate greenhouse effect equivalent to 100 Pg of carbon dioxide. 

Even more terrifying is the prospect of further methane releases. Given that there already is ~5 Gt in the atmosphere, plus the initial 1 Gt, further releases of 4 Gt of methane would result in a burden of 10 Gt of methane. When applying a GWP of 100 times carbon dioxide, this would result in a short-term greenhouse effect equivalent to 1000 Pg of carbon dioxide.

In conclusion, this scenario would be catastrophic and the methane wouldn't go away quickly either, since this would be likely to keep triggering further releases. While some models project rapid decay of the methane, those models often use global decay values and long periods, which is not applicable in case of such abrupt releases in the Arctic.  

Instead, the methane is likely to stay active in the Arctic for many years at its highest warming potential, due to depletion of hydroxyl and oxygen, while the resulting summer warming (when the sun doesn't set) is likely to keep triggering further releases in the Arctic. 

References

1. Soil organic carbon pools in the northern circumpolar permafrost region 

Tarnocai, Canadell, Schuur, Kuhry, Mazhitova and Zimov (2009)
http://www.agu.org/pubs/crossref/2009/2008GB003327.shtml
http://www.lter.uaf.edu/dev2009/pdf/1350_Tarnocai_Canadell_2009.pdf

2. Climate change: High risk of permafrost thaw

Schuur et al. (2011)
Nature 480, 32–33 (1 December 2011) doi:10.1038/480032a
http://www.nature.com/nature/journal/v480/n7375/full/480032a.html
http://www.lter.uaf.edu/pdf/1562_Schuur_Abbott_2011.pdf

3. Science Blog: Submarine Methane Hydrate: A threat under anthropogenic climate change?

Stephen Hunter and Alan Haywood (2011)

http://climate.ncas.ac.uk/ncas-science-blog/241-science-blog-submarine-methane-hydrate-a-threat-under-anthropogenic-climate-change

4. Methane release from the East Siberian Arctic Shelf and the Potential for Abrupt Climate Change

Natalia Shakhova and Igor Semiletov (2010)
http://symposium2010.serdp-estcp.org/content/download/8914/107496/version/3/file/1A_Shakhova_Final.pdf

5. Extensive Methane Venting to the Atmosphere from Sediments of the East Siberian Arctic Shelf
Shakhova et al. (2010)
http://www.sciencemag.org/content/327/5970/1246.abstract

6. Berkeley Lab and Los Alamos National Laboratory (2011)
http://newscenter.lbl.gov/feature-stories/2011/05/04/methane-arctic/

https://www.mcgill.ca/newsroom/news/item/?item_id=212872

7. Anomalies of methane in the atmosphere over the East Siberian shelf: Is there any sign of methane leakage from shallow shelf hydrates? 

Shakhova, Semiletov, Salyuk and Kosmach (2008)
http://www.cosis.net/abstracts/EGU2008/01526/EGU2008-A-01526.pdf

8. Global Warming Potential

Intergovernmental Panel on Climate Change (IPCC, 2007)

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-10-2.html#table-2-14

9. Runaway global warming 

Sam Carana (2011)
http://runawaywarming.blogspot.com

10. Carbon Tracker 2010 - Flux Time Series - CT2010 - Earth System Research Laboratory
U.S. Department of Commerce | National Oceanic & Atmospheric Administration (NOAA)

http://www.esrl.noaa.gov/gmd/ccgg/carbontracker/fluxtimeseries.php?region=All_Land#imagetable

11. On carbon transport and fate in the East Siberian Arctic land–shelf–atmosphere system

Semiletov et al. (2012)
http://iopscience.iop.org/1748-9326/7/1/015201