Greenland Sea hit by M5.3 Earthquake

An earthquake with a magnitude of 5.3 on the Richter scale hit the Greenland Sea near Svalbard on October 28, 2013.

[ Earthquake indicated by orange dot - click on image to enlarge ]

For a long time, huge sea surface temperature anomalies have shown up in the area where the earthquake hit. The image below compares the situation before and after the earthquake hit.

[ click on image to enlarge ]

These huge sea surface temperature anomalies were discussed before, in the September 19, 2013, post Is the North Pole now ice-free?

This post mentions that sea surface temperatures in some spots close to Svalbard are far higher than even in the waters closer to the Atlantic Ocean. In some of these spots, sea surface temperatures are well over 10°C (50°F).

The post continues: Where does this heat come from? These hot spots could be caused by undersea volcanic activity; this is the more dangerous as this area has seen methane bubbling up from destabilized hydrates before; the dangers of this situation have been discussed repeatedly, e.g. in the April 2011 post Runaway Global Warming.

Indeed, the big danger is large abrupt release of methane from destabilized hydrates. At the moment, the amount of methane entering the atmosphere over the Arctic Ocean is already huge, as illustrated by the image below that shows high methane readings over the past few days.

[ click on image to enlarge ]

We'll keep monitoring the situation.

Expedition to study methane gas bubbling out of the Arctic seafloor

The black rectangle on this map shows the general region
where Paull and his collaborators have been studying
methane releases in the Beaufort Sea. The smaller red
rectangle indicates the edge of the continental shelf and
continental slope where they will conduct research during t
heir current expedition. These areas are shown in greater
detail in the maps below. Base image: Google Maps

Chasing gas bubbles in the Beaufort Sea

In the remote, ice-shrouded Beaufort Sea, methane (the main component of natural gas) has been bubbling out of the seafloor for thousands of years. MBARI geologist Charlie Paull and his colleagues at the Geological Survey of Canada are trying to figure out where this gas is coming from, how fast it is bubbling out of the sediments, and how it affects the shape and stability of the seafloor. Although Paull has been studying this phenomenon for a decade, his research has taken on new urgency in recent years, as the area is being eyed for oil and gas exploration.

In late September 2012, Paull and his fellow researchers will spend two weeks in the Beaufort Sea on board the Canadian Coast Guard ship Sir Wilfred Laurier, collecting seafloor sediment, mapping the seafloor using sonar, installing an instrument that will "listen" for undersea gas releases, and using a brand new undersea robot to observe seafloor features and collect gas samples.

This will be Paull's third Beaufort Sea expedition. As in previous expeditions, he will be working closely with Scott Dallimore of Natural Resources Canada's Geological Survey of Canada and Humfrey Melling of Fisheries and Oceans Canada's Institute of Ocean Sciences.

Paull's work in the Arctic started in 2003, with an investigation into the enigmatic underwater hills called "pingo-like features" (PLFs) that rise out of the continental shelf of the Beaufort Sea. (Pingos are isolated conical hills found on land in some parts of the Arctic and subarctic.)

Over time, the focus of the team's research has moved farther offshore, into deeper water. Their second expedition in 2010 looked at diffuse gas venting along the seaward edge of the continental shelf. The 2012 expedition will focus on three large gas-venting structures on the continental slope, at depths of 290 to 790 meters (950 to 2,600 feet).

This idealized cross section of the continental shelf and
continental slope in the Beaufort Sea shows zones in the
seafloor where permafrost and methane hydrate are
likely to exist, as well as hypothetical locations of methane
seeps on the seafloor. Ocean depths not shown to scale.
Image: © 2012 MBARI

Frozen gas—a relict of previous ice ages

The Beaufort Sea, north of Canada's Yukon and Northwest Territories, is a hostile environment by any definition of the term. It is covered with ice for much of the year. Historically, only from mid-July to October has a narrow strip of open water appeared within about 50 to 100 kilometers (30 to 60 miles) of the coast. Even at this time of year, winds often howl at 40 knots and temperatures can drop well below freezing at night. Researchers must allow extra time for contingencies such dodging pack ice and having to shovel snow off the deck of the research vessel.

Average annual air temperatures along the coast of the Beaufort Sea are well below freezing. Thus deeper soils remain permanently frozen throughout the year, forming what is called permafrost. Around the Beaufort Sea, permafrost extends more than 600 meters (about 2,000 feet) below the ground.

Permafrost also exists in the sediments underlying the continental shelf of Beaufort Sea. This permafrost is a relict of the last ice age, when sea level was as much as 120 meters lower than today. At that time, areas that are now covered with seawater were exposed to the frigid Arctic air.

As sea-level rose over the last 10,000 years, it flooded the continental shelf with seawater. Although the water in the Beaufort Sea is cold—about minus 1.5 degrees Centigrade—it is still much warmer than the air, which averages minus 15 degrees C. Thus, as the ocean rose, it is gradually warmed up the permafrost beneath the continental shelf, causing it to melt.

Quite a bit of methane, the main component of "natural gas," is trapped within the permafrost. As the permafrost melts, it releases this methane, which may seep up through the sediments and into the overlying ocean water.

The deeper sediments of the Beaufort Sea also contain abundant layers of methane hydrate—an ice-like mixture of water and natural gas. As the seafloor has warmed, these hydrates have also begun to decompose, releasing additional methane gas into the surrounding sediment.

These maps show the area to be studied during the
current expedition. The lower map shows the continental
shelf and continental slope of the Beaufort Sea. The
upper image shows detailed seafloor bathymetry of a
portion of the continental slope that will be studied
during the current cruise, as well as the three seafloor
mounds that the researchers will explore using their
new ROV. Lower image modified from Google Maps.
Upper image: Natural Resources Canada.

A tantalizing glimpse

A 2010 expedition by Paull and his colleagues provided a tantalizing glimpse of how much methane is present on the continental shelf of the Beaufort Sea. Using a remotely operated vehicle (ROV) with video camera to explore the shelf edge, they found white mats of methane-loving bacteria almost everywhere. They also videotaped what turned out to be methane bubbles emerging from many of these mats. Based on these observations, as well as the contents of sediment cores collected by the Geological Survey of Canada, the researchers concluded that the shelf edge is an area of "widespread diffuse venting" and that "methane permeates the shelf edge sediments in this region."

During 2010, the research team also conducted ROV dives on a shallow underwater mound called Kopanoar PLF. At the top of this mound they discovered "vigorous and continuous gas venting" that released clouds of bubbles and sediment into the water. In one ROV dive, the researchers saw something no one had ever seen before—a plume of gas bubbles that moved rapidly along the sea floor, apparently following a crack in the sediment that was in the process of being forced open by the pressure of the gas coming up from below.

The researchers also studied several deeper PLFs during the 2010 expedition. They dropped core tubes into the tops of these mounds. When the cores were lifted back onto the ship, the sediments inside fizzed and bubbled for up to an hour. The sediment was chock full of methane hydrates. Paull said, "We knew that there was a lot of gas venting going on down there, and now we have good reasons to believe that methane hydrates are present within the surface sediments. But our ROV couldn't dive deep enough, so we weren't able to go down and see what these areas actually looked like." That's one reason the team is heading back to the Arctic in 2012.

MBARI researchers tested this new mini-ROV
in the institute's test tank before sending it out
to face the challenges of the Arctic Ocean.
Image: Todd Walsh © 2012 MBARI

Heading back for more

For the 2012 expedition, the team will continue its strategy of following the topography to study areas of gas venting in the Beaufort Sea. They plan to focus on three circular, flat-topped mounds on the continental slope. The researchers believe that these pingo-like features form at the tops of "chimneys" or conduits where methane is seeping up from sediments hundreds of meters below the seafloor.

During his previous cruises, Paull used a small ROV that could dive only about 120 meters below the surface. However, the mounds on the continental slope are in about 300 to 800 meters of water. So MBARI engineers Dale Graves and Alana Sherman designed and built an entirely new ROV just for this expedition. The new ROV is small, portable, agile, relatively inexpensive, and can dive to 1,000 meters. It can also be launched and operated by just two people (for the 2012 expedition, those two people will be Graves and Sherman).

Amazingly, the new mini-ROV went from initial design to final field tests in only 15 months. But the vehicle's simple yet elegant design reflects Graves' decades of experience designing ROVs and underwater control systems. "It was a fun project for me," Graves said. "A dream come true. We designed it from scratch with a budget of just $75,000, not including labor. We mostly reused parts from MBARI's older ROVs, and built the rest in house. MBARI's electrical and mechanical technicians and machinists worked on it in between their other projects."

In addition to a state-of-the-art high-definition video camera, the ROV carries a special system for collecting methane gas bubbles. This is not as easy as it sounds, because the methane gas has a tendency to turn back into solid methane hydrate, which blocks the flow of any additional methane gas into the system. The new ROV's gas collection system includes a built-in heater to melt the hydrates and keep the gas flowing.

In addition to collecting samples of gas, the ROV will be used to look for communities of tubeworms or clams that typically grow around seafloor methane seeps. Paull said, "Nobody has ever found a living chemosynthetic biological community in the Arctic proper. But I think we have a good chance of finding them at the tops of these structures."

Dale Graves tests the control system for MBARI's new
mini-ROV in the lab before the Arctic expedition.
The entire system fits in just three small shipping cartons.
Image: Todd Walsh © 2012 MBARI

Addressing the big questions

Although the researchers have begun to understand where the gas in the Beaufort Sea is coming from, many other questions remain. One of the big questions the researchers are trying to answer is whether the three gas chimney structures on the continental slope are related to the gas venting systems in shallower water, on the continental shelf. As Paull put it, "Are they independent gas-venting structures that just happen to be together, or are they all part of the same system?"

Another important question is how all this methane gas affects the stability of the seafloor. When methane hydrates warm up and release methane gas, the gas takes up much more space than the solid hydrate, putting pressure on the surrounding sediments. Similarly, the decomposition of either methane hydrate or permafrost can reduce the mechanical strength of the surrounding sediment. Either process could make the seafloor more susceptible to submarine landslides.

Undersea landslides are common along the continental slope of the Beaufort Sea, but researchers do not yet know when or how they form. However, decomposing methane hydrates are believed to have triggered major landslides in other deep-sea areas. Such landslides could potentially destabilize oil platforms, pipelines, or other equipment on the seafloor, and have the potential to generate tsunamis.

If there is time during the 2012 cruise, the researchers hope to perform ROV dives on one or more underwater-landslides. In Fall 2013, when the team returns to the Beaufort Sea for a fourth time, these features will become the primary focus. During that expedition, the team also hopes to use one of MBARI's autonomous underwater vehicles (AUVs) to make very detailed maps of the shelf edge, the underwater landslides, and areas where methane is bubbling out of the seafloor.

Oil and gas companies have known for decades that deep oil and natural gas deposits exist in the sediments below the continental slope of the Beaufort Sea. With the warming of the Arctic and the retreat of sea ice, these hydrocarbons have become more accessible. However, it remains to be seen whether they can be extracted safely, economically, and without excessive environmental damage. Thus, the team's research will not only provide new insights into previously unknown geological processes, but will also provide important information for decision-makers involved in oil and gas permitting.

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For more information on this article, please contact MBARI.

Related links:

• Charlie Paull's web site describing first-hand observations of methane bubbling out of seafloor during the Arctic 2010 expedition (includes video clips).
• Article describing the origin of seafloor mounds in the Beaufort Sea.
• Article on Paull's initial research regarding pingos and pingo-like-features on the seafloor.
• Charlie Paull's web site
• Web site of the Geological Survey of Canada

Source: Monterey Bay Aquarium Research Institute news release

AMEG Position Statement

DECLARATION OF EMERGENCY

Position Statement - Arctic Methane Emergency Group (AMEG) 

We declare there now exists an extremely high international security risk* from abrupt and runaway global warming being triggered by the end-summer collapse of Arctic sea ice towards a fraction of the current record and release of huge quantities of methane gas from the seabed. Such global warming would lead at first to worldwide crop failures but ultimately and inexorably to the collapse of civilization as we know it. This colossal threat demands an immediate emergency scale response to cool the Arctic and save the sea ice. The latest available data indicates that a sea ice collapse is more than likely by 2015 and even possible this summer (2012). Thus some measures to counter the threat have to be ready within a few months.

The immediacy of this risk is underlined by the discovery of vast areas of continental shelf already in a critical condition as a result of the warming of the Arctic Ocean seabed. Increasingly large quantities of methane are being emitted from the seabed. Moreover there is the possibility of methane held as hydrates or under thawing permafrost being suddenly released in very large quantities due to some disturbance such as an earthquake. The quantities of methane in the continental shelf are so vast that a release of only one or two percent of the methane could lead to the release of the remaining methane in an unstoppable chain reaction. Global warming would spiral upward way beyond the 2 degrees which many scientists consider the safety limit.

However we do not take a defeatist attitude towards this extremely dangerous situation. The present challenge to overcome almost impossible odds is reminiscent of World War 2. There exist the talent, technology and engineering skills to fight against these odds and win, given determination, focus and collaboration.

Governments must adopt a plan of action to cool the Arctic, halt the retreat of the Arctic sea ice and slow the release of methane. A variety of means of cooling the Arctic are available, some of which may be classed as geoengineering.

Governments must also take rapid measures to reduce short-lived climate forcers, such as methane and black carbon (commonly known as soot), especially where emitted at high northern latitudes.

Governments must furthermore put in place the necessary monitoring procedures for assessing the situation, allowing accurate modelling and determining the effectiveness and safety of the measures taken.

But intervention on a large scale has to be accepted in order to avert the ultimate catastrophe of runaway global warming. No amount of adaptation or insulation could make that survivable. We demand for all nations to pull together in battle against these threats. We consider it a moral duty: to fight against destruction of the climate system in order to protect the lives of all citizens.

Note that AMEG considers that the cooling of the Arctic should be seen one of many efforts to bring the atmosphere and oceans back towards their pre-industrial state, especially since such efforts reduce both immediate and longer-term risks arising from Arctic warming, sea ice retreat and methane release. AMEG is fully supportive of these efforts.

Source: http://AMEG.me

Abrupt release of methane in the Arctic in late 2011?

Was over 2 Megaton of methane released abruptly from hydrates in the Arctic in late 2011? Satellite images show high levels of methane at various locations in the Arctic over a period of 13 days (November 26, 2011, to December 8, 2011).

Methane was observed at various locations in the Arctic at levels of about 2000 parts per billion. Global levels are about 1820 parts per billion.

What could have caused these high levels in the Arctic?

There are no natural gas pipes at the North Pole that could be leaking, there are no drilling activities taking place, and there are no cows or termites. Since it was winter at the time, there were no algae blooms.

The best way to explain these high levels of methane at the North Pole is that was venting from hydrates at the North Pole and carried by the wind into North America.

Global wind circulation patterns - NSIDC image

In which direction would methane flow?

Polar easterlies are the prevailing wind patterns in the Arctic. When methane emerges at surface levels in the Arctic, these winds will drive it down to 60 degrees North latitude, where it will be further dispersed by the Polar Jet Stream (or Polar front).

How fast can methane be carried by the wind?

In the Arctic, winds have average speeds of 600 to 1032 kilometers per day on the Atlantic side in winter, while maximum wind speeds in the Atlantic region can approach 4320 kilometers per day in winter (Rajmund Przybylak, 2003: The Climate of the Arctic).

By comparison, the distance between Murmansk and Svalbard is about 1000 km (621 miles), as illustrated on the above map.

The animation below shows daily satellite pictures of methane descending down the Arctic, from the North Pole into North America over a period of 13 days (November 26, 2011, to December 8, 2011). Distances traveled daily appear to match average wind speeds for the respective area at this time of the year.

Note: This is a 2.17 MB file; it may take some time for the animation to fully load.

In conclusion, the animation suggests that methane is venting from hydrates in the Arctic at levels up to 2000 parts per billion. These high levels can cover areas as large as Greenland. Total surface of Earth is 510,072,000 square kilometers, and Greenland has a surface of 2,166,086 square kilometers, one 235th that of Earth.

The total methane burden on Earth is about 5 Gt, corresponding with a level of 1820 parts per billion. Thus the burden over an area the size of Greenland would be one 235th of 5 Gigaton, or 21 Megaton. A level of 2000 parts per billion is about ten percent higher than the world's average level of 1820 parts per billion. Thus, the methane that shows up in the animation could result from abrupt release of some 2.1 Megaton of methane from hydrates in the Arctic.