Retreating Ice Sheets Spurred Massive Methane Expulsions from Arctic Sea Floor

Ice sheets provided perfect conditions for subglacial gas hydrate formation, but…

A new study published in Science shows that hundreds of massive, kilometer-wide craters, were formed on the Arctic ocean floor following substantial methane blowouts about 12,000 years ago.

Abstract

Widespread methane release from thawing Arctic gas hydrates is a major concern, yet the processes, sources, and fluxes involved remain unconstrained. We present geophysical data documenting a cluster of kilometer-wide craters and mounds from the Barents Sea floor associated with large-scale methane expulsion. Combined with ice sheet/gas hydrate modeling, our results indicate that during glaciation, natural gas migrated from underlying hydrocarbon reservoirs and was sequestered extensively as subglacial gas hydrates. Upon ice sheet retreat, methane from this hydrate reservoir concentrated in massive mounds before being abruptly released to form craters. We propose that these processes were likely widespread across past glaciated petroleum provinces and that they also provide an analog for the potential future destabilization of subglacial gas hydrate reservoirs beneath contemporary ice sheets.

The giant craters were formed about 12,000 years ago, but are still seeping large quantities of methane and other gases. Illustration: Andreia Plaza Faverola. Source: CAGE

The craters were formed about 12,000 years ago; however, methane is still leaking profusely from them.

“The crater area was covered by a thick ice sheet during the last ice age, much as West Antarctica is today. As climate warmed, and the ice sheet collapsed, enormous amounts of methane were abruptly released. This created massive craters that are still actively seeping methane” says Karin Andreassen, the study lead author and professor at CAGE Center for Arctic Gas Hydrate, Environment and Climate at UiT The Arctic University of Norway.

Related Links

• https://cage.uit.no/news/massive-craters-formed-methane-blow-outs-arctic-sea-floor/

Arctic sea ice maximum extent shrinks to new record low

Record low Arctic sea ice maximum extent also occurs early this year

Arctic sea ice extent appeared to have reached its annual maximum extent at 14.54 million square kilometers (5.61 million square miles), on February 25, 2015, marking an early start of the melt season, said National Snow and Ice Data Center (NSIDC). 

The 2015 maximum extent occurred 15 days earlier than the 1981 to 2010 average date of March 12, however, a late season surge in ice growth could still occur, said NSIDC, adding that it will post a detailed analysis of the winter sea ice conditions in April.

Measured at 14.54 million square kilometers (5.61 million square miles), the lowest in the satellite record that began in 1979. the ice probably reached its maximum extent for the year on February 25.  The maximum extent was 1.10 million square kilometers (425,000 square miles) below the 1981 to 2010 average of 15.64 million square kilometers (6.04 million square miles) and 130,000 square kilometers (50,200 square miles) below the previous lowest maximum that occurred in 2011, said NSIDC.

Below-average ice conditions were observed everywhere except in the Labrador Sea and Davis Strait.  This year’s maximum occurred 15 days earlier than the 1981 to 2010 average date of March 12. The date of the maximum has varied considerably over the years, occurring as early as February 24 in 1996 and as late as April 2 in 2010.

“Over the next two to three weeks, periods of increase are still possible. However, it now appears unlikely that there could be sufficient growth to surpass the extent reached on February 25.”

Arctic sea ice extent for February 25, 2015 was 14.54 million square kilometers (5.61 million square miles). The orange line shows the 1981 to 2010 median extent for that day. The black cross indicates the geographic North Pole. Sea Ice Index data. About the data. Credit: National Snow and Ice Data Center. High-resolution image

Temperatures throughout the eastern Arctic were several degrees Celsius above average at the 925 hPa level (approximately 1,000m, or 3,000 feet altitude) during the first half of March, and climbed as much as 8 to 10 degrees Celsius (14 to 18 degrees Fahrenheit) above average in the Barents Sea between Svalbard and Franz Josef Land, reported NSIDC.

Minimum Ice Extent

The Arctic sea ice will reach its annual minimum extent in September (assuming that there would still be some ice left this year!)

The ice reached its lowest minimum cover in 2012 with 2.11 million square kilometers (1.31 million square miles), which was about 483,000 square kilometers (300,000 square miles), or 18.6 percent, lower than the previous record low of 2.59 million square kilometers set in 2007.

Bering Sea Drilling Revisited!

Update: Bush to urge lifting of ban on offshore drilling
“With gasoline now over $4 a gallon, tomorrow he will explicitly call on Congress to also pass legislation lifting the congressional ban on safe, environmentally friendly offshore oil drilling,” White House spokeswoman Dana Perino said on Tuesday.

Offshore Drilling

The following post is a reply to Dan Daniels who recently visited this blog and left a comment at Bering Sea Drilling .

Dan Daniels wrote:

I was the District Manager for Sedco Forex responsible for exp[l]oration activities on the West Coast of the US including the Bering Sea. I had two semi-submersible drilling vessels working in the Bering Sea when environmental concerns required us to cease drilling activities.

In the 8 plus years we, as a company, operated in this area we NEVER had an environmental issue (not so much as a st[y]rofoam cup going over the side) – this with daily high scrutiny from the Department of the Interior. I even received an award on behalf of our company for this accomplishment.

I believe strongly that with proper controls, commitment from management, training and overview offshore drilling can be accomplished without detriment to the environment. The issue lies almost exclusively with shipping the product, not developing the field. We should make every effort to carry out the require exploration and focus our efforts on improving the transportation aspects of moving the petroleum products

An offshore Oil/Gas platform.

Mr Daniels,

We [the FEWW moderators] believe the problems are much more extensive than you have stated. The areas of greatest concern are

1. Impacts of excessive energy consumption.
2. Climate Change.
3. Other impacts of excessive CO2 and other GHG pollution created by the consumption of fossil fuels, e.g., oceans acidification.
4. Marine pollution, habitat destruction and other damage caused by offshore oil and gas drilling including

• Exploration
• Production
• Transportation
• Storage
• Delivery

The specific items of concern include:

• Flaring and venting
• greenhouse gas emissions
• Decommissioning of oil and gas installations
• oil storage tank disposal
• Pollution created by drill cuttings
• Produced waters, muds and fluids
• Subsidence
• Spills
• piping
• Environmental impact of products
• Health impact of processes in products
• Spoilage of sensitive ecological areas and habitat destruction
• Waste disposal
• Health impact of processes in products
• Impact on Marine Mammals and other life forms
• Human Health Impact
• Climate Change
• Release of benzene, methanol, sulfur and other harmful chemicals to the environment
• Discharge of ballast waters
• Release of tank cleaning water
• Impact on ecosystems

The following excerpts are from Sense and Nonsense:The Environmental Impacts of Exploration on Marine Organisms Offshore Cape Breton, by David Lincoln.

Sense and Nonsense

The environmental impacts of the Oil and Gas Industry’s exploration operations are pervasive. No country or province which has been exposed to a prolonged history of offshore hydrocarbon exploration has been left untouched by the inevitable accidents and unforeseen consequences of the petroleum industry.

The fishing industry is usually the first sector to be impacted by these exploration activities. This normally occurs when fishermen are told to remove their boats and gear from an area so that a seismic vessel can begin generating noises.

By far the loudest noises generated by the offshore petroleum industry are those produced by seismic survey equipment. This equipment is designed to create very loud noises, the echoes of which reflect off geological strata deep within the seabed and are used to locate likely places for drilling wells. The sounds were at one time made by explosives, which could kill fish at a range of some hundreds of meters, but the almost universal seismic equipment now used offshore is an array of “airguns”.

Seismic Effects on Fish and Marine Mammals

Experiments on the effects of seismic shooting on abundance and catch of cod and haddock were conducted in the Barents Sea. The Norwegian studies looked at the effects of an airgun using a combination of scientific-survey and commercial fishing techniques. The fish survey work extended across a circle 40 nautical miles in diameter (a maximum range of some 33 km from the airgun survey area) and continued until five days after the seismic work was completed..”

Since the fall of the Iron Curtain, information has begun to flow out about the Russian experience with decades of exploration activity in the Caspian and Barents Seas. These reports differ markedly from the rather subdued observations in Western Bloc countries. Dr Stanislav Patin in his 1999 book entitled “Environmental Impacts of the Offshore Oil and Gas Industry” recalls a catastrophic ecological situation in the Caspian Sea in the 1960’s. “I was a member of the Special Government Committee on this issue and witnessed firsthand the dramatic ecological consequences of the explosive use, including mass mortality of Caspian sturgeons (up to 200,000 large specimens).”

Exploration Drilling

Despite industry claims, the companies do not yet know for certain which type of hydrocarbon (oil, gas, condensate or a combination of these fluids. will be encountered). Vintage seismic data from the 1980’s cannot accurately distinguish between oil and gas and geochemistry, if available, is often difficult to interpret. Before drilling, the companies will conduct a hazard survey primarily to reduce the chances of encountering shallow gas which could be disastrous.

Shallow seismic surveys of the upper few hundred meters of the seabed are often carried out to determine the structure of the sediments and scan for potential hazards to drilling (e.g., shallow gas pockets). These hazards will be described in greater detail in the section on shallow gas blowouts.

The Drilling Phase

Under normal circumstances, the predominant discharges during drilling, would be the “cuttings”; small chips of rock cut by the drill in forming the well, and the “muds” used in the drilling process to cool and lubricate the drill, carry the cuttings out of the hole and counter-balance the pressure of gas, when that is reached. These discharges, their fates and their environmental effects have been the most intensively studied (and argued) aspect of the offshore petroleum industry’s environmental effect.

Mud and Cuttings Discharges: Water Based Muds (WBMs)

Besides their intended constituents, drill muds, both Water Based Muds (WBMs) and Oil Based Muds (OBMs), often contain high levels of heavy metal contamination. WBMs, despite their water base, also often contain appreciable amounts of oil: under some circumstances, it is necessary to add a “pill” of oil to the circulating WBM and this is usually left in the mud, gradually being dispersed through it and ultimately discharged
with it.

The overall quantities of WBM discharged can be high. While the water naturally disperses into the ocean, the other constituents represent substantial contamination. The eight exploratory wells drilled with WBM on Georges Bank in 1981-2, for example, resulted in some 4000 tons of barite and 1500 tons of bentonite clay being discharged.

Mud and Cuttings Discharges: Water Based Muds (WBMs)

Besides their intended constituents, drill muds, both Water Based Muds (WBMs) and Oil Based Muds (OBMs), often contain high levels of heavy metal contamination. WBMs, despite their water base, also often contain appreciable amounts of oil: under some circumstances, it is necessary to add a “pill” of oil to the circulating WBM and this is usually left in the mud, gradually being dispersed through it and ultimately discharged with it.

The overall quantities of WBM discharged can be high. While the water naturally disperses into the ocean, the other constituents represent substantial contamination. The eight exploratory wells drilled with WBM on Georges Bank in 1981-2, for example, resulted in some 4000 tons of barite and 1500 tons of bentonite clay being discharged.

Water-Based Mud

The composition of drilling mud may be changed often during drilling in response to conditions encountered. In practice, this usually means that mud weight is gradually increased by adding barite and other chemicals to control the natural pressure increase with depth. When this happens suddenly, the mud is dumped in bulk and a new batch is mixed (often with heavier properties in anticipation of increased pressure). Analysis of the drilling waste scenario data (volume density and weight) could yield a likely
composition. It is indeed strange that adult scallops are highly sensitive to barite but show relatively low sensitivity to used water based mud cuttings.

Furthermore, dozens of organisms have already been subjected to varying compositions of drilling mud and the toxicity results are known and well reported. Of 415 acute lethal bioassays lasting 48-144 hrs with 68 drilling muds involving 70 species, 8% showed 50% mortality (LC50) below 10,000 ppm.

Ecosystem Impacts

“There is concern that the routine discharge of wastes during drilling for oil and gas could impact valuable fishery resources. Recent studies have indicated that intensive drilling efforts in the North Sea have caused detrimental effects in adult and larval fish and benthic invertebrates at greater distances from drilling platforms than previously envisaged”.

Abundance of benthic organisms near one N.J. rig site plunged from 8011 animals /sqm before drilling to 1729 animals /sq m. during drilling. One year after drilling was completed, the number had risen to only 2638 animals /sq m. Diversity was also impacted from 70 to 38 species /0.02 sq m rebounding only to 53 species /0.02 sq m one year afterwards.

Discharges and Shellfish

Laboratory experiments have shown barium uptake, from WBM-contaminated sediments and foods, by both flounder and lobster juveniles but there does not seem to be any evidence for its biomagnification up the food chain. In the experimental setting, the contaminants suppressed growth of both species and enhanced lobster mortality but this was with concentrations of 9 g barium per kilogram of sediment and a 98 or 99-day …

Certainly, its finer grain size should ensure that it is at least as mobile as the barite and probably more so. Recent research has shown that scallops are peculiarly susceptible to barite and bentonite, prolonged exposure to even concentrations as low as 10 mgl-1 (less than 10 ppm) being fatal, while levels as low as 2 mgl-1 can affect scallop growth.

“As mush as 90% of the discharged solids settle directly to the bottom. (Brandsma 1980). The remaining 10% including clay-sized particles and soluble materials is diluted by the current and dispersed over large areas8. ” Furthermore “during the entire [one well] scenario a total of 468 MT of drilling mud and 2569 MT of cuttings are released to the marine environment.

Now that it has been shown that drilling eight wells spread detectable levels of barite over much of Georges Bank, the COPAN drilling near Sable Island spread flocculant material some kilometers from the source, Norwegian oil production has affected benthic communities over some 100 sq km around major platforms and that background sediment hydrocarbon levels seem to be rising in the United Kingdom sector of the North Sea, the relevance of such impacts can no longer be ignored.

Shallow Gas Blowouts

One of the greatest risks to the environment during the exploration phase is a shallow gas blowout. This is particularly true if the flow is associated with a condensate discharge which frequently occurs. […] Once flow has started, it is almost inevitable that a blowout will occur.

“Cratering occurs when flow outside the casing displaces large volumes of surface sediment. The eruptive force of blowouts can be dramatic and has been documented as lifting large boulders weighing several hundred pounds into the air and dropping them as much as 150 ft from the well site.

“Records show that if a shallow gas blowout does not bridge within the first one to two days, then the well will probably continue to blow for an extended period of time, i.e., weeks or months. Some have continued for years.”

Adams includes a chart condensed from a database of 950 shallow gas blowouts. Of the 56 rigs listed more than half suffered extensive damage or the total loss of the rig.

The truth is that the biological impacts of gas and condensate spills have been poorly studied until recently. Even the Uniacke gas blowout which released condensate in 1984 was not evaluated for biological impacts. Gas blowouts such as occurred in India in 1999 are poorly reported and not studied in detail. It is ludicrous for the industry to argue that gas wells have little impact on the ecosystem when they have not looked carefully at the marine organisms effected and no long-term studies on productivity or reproductive success following exposure are known to exist.

Related Links:

• Bering Sea Drilling

List of references cited for Sense and Nonsense:The Environmental Impacts of Exploration on Marine Organisms Offshore Cape Breton, by David Lincoln, is available at the URL: http://www.sierraclub.ca/national/oil-and-gas-exploration/sense-and-nonsense.pdf

feww

Wind Energy in Norway, Nuclear in F*nland

Are the Norwegians More Intelligent Than the Finns?

Top 10 Reasons why the Norwegians May Be More Intelligent that the Finns [then again …]:

10. Finland with an estimated population of 5.32million, most of whom are intoxicated most of the time [no offense intended, just citing a matter of fact relayed to us by a Finnish colleague,] wants more nuclear energy despite the fact … well read it for yourself: More nuclear power and How Do You Say ‘Duck-n-Cover’ in Finnish?

As for our Norwegian [distant] cousins, the North Sea gas pipeline operator Gassco has just awarded [Aug 20, 2008] Sweden’s Marine Matteknikk AB “a contract to survey 636 km of seabed for potential pipelines to carry carbon dioxide to offshore burial sites.” (Source)

Let’s hope there’ll never be an earthquake on the Norwegian Continental shelf.

Continued …