Archives for category: methane hydrates

Tuesday 1 to Wednesday 2 July 2014

For the previous 2 days of the MAGIC campaign we have carried out work around Svalbard to look for methane hydrate emissions off the west coast of the archipelago and to test a new inertial navigation system at high latitudes.

On Tuesday we left Kiruna in Northern Sweden at 0900 UTC (which is another way of saying GMT), transiting at high level before descending to 100 ft above sea level to rendezvous with the Norwegian research ship, the RV Helmer Hanssen, currently carrying out a survey of the methane above seabed bubble plumes, and looking for elevated methane in the atmosphere. We flew past the ship twice before heading to Longyearbyen to refuel and prepare for the next sortie of the day.

The second sortie was a 1400 UTC take off heading out to 10°E then to 84°N at 27000 ft. Stratospheric air was encountered at these high latitudes. Following a leg at 84°N across to 20°E and a successful navigation equipment test we headed back to the 10°E line heading for lower altitudes to look for methane emissions above leads (wide cracks) in the Arctic sea ice pack. Our descents to 100 ft were very intermittent due to low cloud cover, but lead development was seen near 81.5°N, and these became more frequent as we flew south. The edge of the ice pack was close to 80.1°N and fragments of ice from the pack were observed to 79.9°N. Methane seemed to increase very slightly after reaching open water but changes were not much above instrument measurement precision.

Ice break-up 81°N (Photo: Dave Lowry)

Ice break-up 81°N (Photo: Dave Lowry)

Melting Ice

Melting ice rafts at 80.5°N (Photo: Dave Lowry)

Edge of sea ice at 80.1°N.(Photo: Dave Lowry)

Edge of sea ice at 80.1°N.(Photo: Dave Lowry)

After debrief we headed to the centre of Longyearbyen. The taxi drivers have plenty of great stories about the town, some not appropriate for print. We stayed in the Radisson hotel, which apparently was transported from Lillehammer after the 1994 winter Olympics. The cloud cover made the town quite gloomy, not helped by the remnants and scars of coal mining on the hillsides, although residential developments do add some colour.

MAGIC leader, John Pyle,  a long way from home.

MAGIC leader, John Pyle, a long way from home.

Midnight cloud and fjord at east edge of Longyearbyen (Photo: Dave Lowry)

Midnight cloud and fjord at east edge of Longyearbyen (Photo: Dave Lowry)

Longyearbyen residents invited to contribute to biomethane project? Only joking. (Photo: Dave Lowry)

Longyearbyen residents invited to contribute to biomethane project? Only joking. (Photo: Dave Lowry)

The first sortie for Wednesday was a 0900 UTC departure aimed at surveying the hydrate bubble line west of Prins Karls Forland where the water depth is approximately 400 m. This has been the focus of extensive acoustic and geophysical study by European groups over the past decade. Many methane bubble plumes have been observed rising from the sea bed, but these tend to dissolve or be oxidized as they rise in the water column and their breaching of the surface is still hotly debated, hence our current atmospheric surveys. The data from the profiles across this zone will now be analysed to see if there is elevated methane, although first impressions are that this is not a very big source in the context of global methane emissions. Frequent sightings of whales and seals were reported back from the flight deck, but from my seat under the wing these went mostly unobserved. A low level (1000 ft) return to Lonyearbyen allowed some great views of the coastal scenery including mountains, glaciers and wetlands.

Southern tip of Prins Karls Forland (Photo: Dave Lowry)

Southern tip of Prins Karls Forland (Photo: Dave Lowry)

Thawing Svalbard wetland (Photo: Dave Lowry)

Thawing Svalbard wetland (Photo: Dave Lowry)

Another hour was spent over the bubble zone after lunch and refuel before climbing to 25,000 ft for the return transit to Kiruna. Spectacular views of the Norwegian coast were a distraction from watching the methane displays until the start of the descent into Kiruna. A plume of long-range transport of emitted methane was observed and sampled between 20,000 and 18,000 ft, and the air mass history will be analysed to interpret the source of this. We landed in Kiruna at 1700 UTC. We had flown around 13 hours in the 2 days and I had collected close to 50 samples of air for subsequent analysis back at Royal Holloway, University of London. So lots of tired crew and scientists but a very rewarding and informative trip. Hope to see a little more of the midnight sun if I get another opportunity to go up there.

Dr Dave Lowry (Royal Holloway, University of London)

Tuesday 1 July

Sea ice north of Svalbard, where we were looking for evidence of methane release. (Photo: John Pyle)

Sea ice north of Svalbard, where we were looking for evidence of methane release. (Photo: John Pyle)

We made it to 84N and did some really good science en route. The second radar altimeter (without which extended flying below 100ft is impossible) was playing up on the ground in Kiruna so I was nervous that we would not be able to do any of the low level work that we’d planned. In the event, it righted itself en route and we were able to fly down to 50ft over the ocean off Svalbard, including flight round the Norwegian research vessel of our MOCA (one of the other projects working on this field campaign) colleagues.

The afternoon flight took us to 84N, a record for FAAM, with a low level return over ice, mixed ice and open ocean to Svalbard. We have got excellent methane data to investigate whether the ocean is a methane source at the edge of the sea ice. It was an exciting flight, if a little too much for Stéph (see photo).

Professor John Pyle, University of Cambridge

An exhausting day, getting up to 84N.

An exhausting day, getting up to 84N. (Photo: John Pyle)

The ARA flying over Spitsbergen in July 2012. (Photo credit: Michelle Cain.)

The ARA flying over Spitsbergen in July 2012. (Photo credit: Michelle Cain.)

Sunday 22nd September.

We’re off the west coast of Spitsbergen (Svalbard is the territory, Spitsbergen is the biggest island), looking for methane plumes coming from the methane hydrates on the seabed below. They’re here, a couple of hundred metres down – but do they break surface? Rebecca Fisher, today sitting by the window, and Mathias Lanoisellé, who was on last year’s flight, were both on the ship that found the plumes. So now we’re running along the track of the plumes, 150 feet above the waves. But today, as last year, we don’t find any methane that has escaped. It has all dissolved in the water, or been ‘eaten’ by methanotropic bacteria in the sea.

That’s comforting – this is a big gas release going on beneath us, and we know it’s there, but at least it isn’t hitting the atmosphere. The hydrates are being warmed by the West Spitsbergen Current, the top end of the Gulf Stream, which is pouring Gulf of Mexico heat into the Arctic Ocean.

Take off

We took off from Kiruna, sopping wet under low skies. The pilots’ mikes were offline on our headphones, but you could hear the quiet comment  when the BAe 146 rotated and lifted off, climbing up towards the hills towards the Norwegian border.  As we unbuckled the top two straps of the 4-way harness, far below in the murk we would have had the wetlands of Abisko park, where we’d been the previous day, off on our west side. James France and Dave Lowry, having volunteered to do the hard stuff while we fly, would be setting off for another wet day there. Meanwhile ten thousand feet up, we’re given good hot coffee and – surprise – superb chocolates (mystery gift: was it the pilots?).

We’re climbing from 10000 towards 25000 feet now, over the border hills between Sweden and Norway. There’s high methane air here. We don’t know where it comes from, but when she’s back in the office, Michelle will run a meteorological model backwards to find out where the methane came from.

There are three snakes writhing across the screen – one’s methane. Below it is CO2. If they both rise together, it’s likely to be industrial air. But if just methane rises, then the source will be natural wetland or maybe hydrate. Below is the water vapour trace, and in an inset is CO and Ozone. If there’s lots of CO, then the air mass may come from a distant giant forest fire – at 25000 ft this maybe was days or even weeks ago and perhaps far away as eastern Russia, or even North America.

Heading for Zeppelin – or at least a few dozen miles west of Zeppelin

There’s a brief excitement – ozone is climbing. Is this a filament of stratospheric air, a down-hanging tendril from above? They saw one on the transit across from the UK a couple of days ago. The Polar Vortex brings the stratosphere down here: some of this polar stratospheric air rose long ago over the giant thunderstorms of the tropics, in what’s called the Brewer-Dobson circulation. But the ozone soon falls again – maybe it was just a little breath now mixing in with the ambient troposphere, left over from something that took place earlier.

We reach the point of descent, far north of Tromso, and then dive fast to begin a sharp sawtooth pattern – down low, then up, then down again, up, down, up, down, up down. We’re hunting – like a hound going to ground, then lifting to sniff upwards,  seeking out the easterly winds from Siberia. There’s some wind at a few thousand feet that’s rich in methane, and we sample it. Down low, the air is very uniform – some wiggles in the snake, but this is well-mixed polar air. This is very good news for the planet, as it means there are no huge point sources feeding blasts of methane into the winds: at least, not this day.

Then the sawtooth pattern ends. We have just enough fuel for a long run at low level over the west coast of Spitsbergen. This is where the methane plumes are, hundreds of them, in a line along the gas hydrate stability boundary 250 to 400m underwater. We watch the wiggles for a sign of methane emissions. The pilots are watching keenly also: “Two birds to the left… and to the right… less than we saw last time…(an engine ate birds once, which can be indigestible)…shower ahead…

Zeppelin Station, Spitsbergen, a few tems of miles east of our flight track.This mountain-crest station run by NILU (the Norwegian Air research Institute) continuously monitors methane.

Zeppelin Station, Spitsbergen, a few tens of miles east of our flight track. This mountain-crest station run by NILU (the Norwegian Air Research Institute) continuously monitors methane. (Photo credit: Euan Nisbet)

All’s quiet – the wiggles stay calm. Back up to 25000 ft and turn for home. We poor souls who have been on the west side of the aircraft listening to the comments about fantastic visibility finally get a glimpse of the astonishing landscape of Spitsbergen. Dave, Rebecca, James and I have all worked there, at Zeppelin Mountain: it’s marvellous to see the sharp teeth – the Spits-bergen – of the jewel of the North again.

–Professor Euan Nisbet, Royal Holloway University of London

Here, Prof. Euan Nisbet provides us with an explainer on methane hyrdates, which could potentially release methane into the atmosphere as the ocean warms, and how we are going to target our measurements to find out more about them. 

The MAMM team board the ARA after refuelling at Longyearbyen, Spitsbergen, during the MAMM field campaign in 2012.

The MAMM team board the ARA after refuelling at Longyearbyen, Spitsbergen, during the  field campaign in 2012. The ARA will soon be sniffing out the methane in the Arctic air. Photo credit: Michelle Cain.

Our flights across the Barents Sea (like the one being attempted today) are designed to assess the methane releases into the Arctic atmosphere. Using knowledge about the wind, the atmospheric research aircraft can ‘sniff’ methane sources thousands of miles upwind from its flight path (note: methane has no smell to humans, but our laser-based instrument is a very sensitive methane-sniffer). The “cavity ring-down spectroscopic” system operated by FAAM (Facility for Airborne Atmospheric Measurements) and the University of Manchester is so sensitive that it can sniff at a precision better than one molecule in every one billion molecules in air – as sensitive than the keenest hound.

There have been many news stories recently about the problem of methane release from the huge amount stored a few hundred metres under the surface in the Arctic, within the enormous deposits of a water-methane structure called methane hydrate. In the past few years, several papers in scientific journals have suggested that huge amounts of methane are already being released from hydrate, and in July this year an article in the prestigious journal Nature modelled the enormous impact this might have (Whiteman et al., Vast costs of Arctic change, Nature, 25th July 2013, 401-3).

To look for methane in the high Arctic, the aircraft flies high and low across the Arctic Ocean. The high flights can measure the methane in the middle of the troposphere (the main part of the atmosphere), while the low flights, close to the sea surface, measure the methane in the “boundary layer” (or near-surface), where surface sources mix up into the winds. By back-tracking the winds, we can sniff methane sources many thousands of miles away and determine where they have come from. For example, if there is an easterly wind, a flight north of Norway can measure methane released by sources far away in northern Russia. This is a sort of methane telescope — or, to use the Greek for nose, a “methane telerhino” — is used just in the way a fox sniffs a chicken coop upwind. Using even more sophisticated methods such as carbon isotopic analysis of the carbon atoms in methane by the Royal Holloway University team, we can tell what “type” of methane it is – for example, whether it is methane that has been emitted from microbes in wetlands or natural fossil gas. Using measurements of other gases from instruments such as a mass spectrometer, we can also say from where those gases originated with greater confidence as we know that certain processes should emit specific gases together (e.g. formic acid and methane in forest fires).

What is hydrate, and why might it be important?

Gas Hydrates (also known as clathrates) are ice-like materials made by gases such as methane and CO2, and water. Think of freezing Coca-Cola. They are stable under pressure and cold temperatures. There can be an enormous amount of gas stored in them, and when they are heated up they release this gas. They exist all round the world where methane gas seeps up into wet sediment in the right pressure and temperature conditions. They occur in the Amazon delta, in the Gulf of Mexico deep oilfields, and very widely in the tropics, stabilised under the pressure of a fairly thick sediment load. In the Arctic the cold temperatures help stabilise hydrate at much shallower depths. Offshore, the sea water a few hundred metres down is close to 0oC and methane hydrates are stable near the seabed under about 300 to 400m of water. Near-shore, in shallow salty water that can be as cold as -2oC, hydrate is stable under a few hundred metres of sediment or less. Onshore, in extremely cold areas where the mean annual temperature can be as low as -10oC, hydrates can be stable quite close to surface.

As hydrates warm, they can potentially release great quantities of methane. This is a powerful greenhouse gas – the warming can then feed the warming. Long ago, in the 1980s, Gordon MacDonald  and Euan Nisbet independently worried that there might be a link between warming hydrates and climate.  An old but more-or-less still valid figure from Nisbet’s 1989 paper (below) shows where the hydrates occur and how they respond to warming.

This figure is ancient, but still more-or-less relevant. The curves show the stability of the hydrates 0.5 to 100 years after a surface warming to +5C. From Nisbet, E. G. (1989).

This figure is ancient, but still more-or-less relevant. The curves show the stability of the hydrates 0.5 to 100 years after a surface warming to +5C. From Nisbet, E. G. (1989).

Nisbet, E. G. (1989), Some northern sources of atmospheric methane – production, history and future implications, Can. J. Earth Sci.26(8), 1603-1611.

MacDonald, G. J. (1990) Role of clathrates in past and future climate change. Climate Change

16, 247-82. See also text of MacDonald’s 1983 comment in http://www.killerinourmidst.com/MH and global climate.html.

Bubbles seen by ships – is the Arctic shelf degassing?

For some years, there has been an extremely interesting annual voyage across the east Siberian Arctic Shelf led by Nathalia Shakhova and Igor Semiletov of the Univ. of Alaska at Fairbanks. This is remarkable scientific work in a very important and little studied region. In 2010, Shakhova et al. reported major methane emissions from the eastern Siberian shelf and suggested the annual outgassing might be as much as 8 million tons, enough to be globally significant (the world emits somewhat over 500 million tons annually from all sources, human and natural). However, in the scientific discussion following the publication, the quantification of the emission was disputed. Much of this shelf is flooded peatland, which can also release methane when the permafrost melts.

Shakhova, et al. (2010) Extensive Methane Venting to the Atmosphere from Sediments of the East Siberian Arctic Shelf. Science 327, 1246

Methane emissions from seabed hydrates were also found off Spitsbergen by a major NERC study from the ship RRS James Clark Ross. About 250 plumes of gas bubbles were seen.   The plumes were discovered by ‘fish-finder’ sonar (more commonly used to search for cod than methane!). Bubble trains came from the edge of the gas hydrate stability zone, and some reached nearly to the surface. Rebecca Fisher and Mathias Lanoisellé from the Royal Holloway group were on the ship (they’ve now taken wings on the FAAM aircraft). The plumes were reported by  Westbrook et al (2009):

Westbrook et al.  (2009) Escape of methane gas from the seabed along the West Spitsbergen continental margin. Geophys. Res. Lett. 36, L15608.

The emissions were in response to seawater warmth, but this was off W. Spitsbergen where the water is at the northerly end of the Gulf Stream, where the warmth is brought north from the Gulf of Mexico.

Is Godzilla about to arise? Is there a methane monster?

In the 25th July issue of Nature this year, Whiteman et al. suggested a monster methane release is about to occur in the Arctic. They modelled a release of 50 Giga-tons of methane from Arctic hydrate, at 5 Gt a year over 10 years from 2015 to 2025. One Giga-ton is 1000 million tons, or 1015 grams.  To put this in context, the total amount of methane in the world’s air now is about 5 Gt, and the annual input is about 0.5 Gt, so this would double the methane in the air within the first year.  They based this number on a  ‘single stage blowout’ scenario from another paper by Shakhova et al, (2010). The Whiteman et al. paper had immediate press interest, from newspapers as prestigious the Guardian and the New York Times to a wide range of  blogs.

Contrary voices were also heard, in particular from researchers on methane and hydrates (including the present author). They were widely sceptical of such large releases. Responses were both published later in Nature, and also a posted comment that is accessible by scrolling far down the page on:

http://www.nature.com/nature/journal/v499/n7459/full/499401a.html

The full text is on:

http://equianos.com/wordpress/wp-content/uploads/Response-to-Whiteman_et-al-Comment.pdf

There’s clearly a great deal of methane hydrate in the Arctic, and much of it is likely to be destabilised by Arctic warming. But is it going to come out as a great sudden burst in a few years? Or is it going to dribble out as a chronic release, as suggested in 2008 by David Archer, a recognised hydrate expert?  Remember also that the northern wetland methane emissions respond very fast to warming. There’s much evidence that at the end of the last glaciation it was not primarily the hydrates but the wetland response that drove the very rapid increase in methane.

Archer, et al (2008) Ocean methane hydrates as a slow tipping point in the global carbon cycle, Proc. Natl. Acad. Sci.  106, 20596–20601

Nisbet, E.G. and Chappellaz, J., (2009) Shifting gear, quickly. Science 324, 477-8

The scepticism of Arctic researchers about the 50 Gt blowout scenario was initially dismissed by an influential Guardian blog as “narrow arguments of scientists out of touch with cutting edge developments in the Arctic.” http://www.theguardian.com/environment/earth-insight/2013/aug/05/7-facts-need-to-know-arctic-methane-time-bomb

However, later the comment was modified:

http://planet3.org/2013/09/05/nafeez-ahmed-responds/#comment-40721

The answers to these puzzles is what we’re trying to find out….

MAMM Flights to the High Arctic

Our MAMM flights are designed to measure the Arctic winds. If the 8 million ton per year methane emission inferred by Shakhova et al (2010) is already happening, this outpouring will produce an excess of methane in the polar air above the regional temperate background. If the winds are suitable, we should be able to detect that as we fly north in the polar air.

The ARA flying over Spitsbergen for MAMM in 2012.

The ARA flying over Spitsbergen for MAMM in 2012.

Of course it all depends on what the winds bring us, but we can go searching. This is what Michelle Cain and colleagues at the UK Met Office do – they use a weather model to predict where the air will come from. In the same way that the modellers predict how clouds of volcanic ash will travel to disrupt airline flights, so they can work out where the air is coming from. That means we can move the aircraft flight path, and go up and down in altitude, to seek out air masses that have come from the Siberian shelf, or from the vast Russian and Siberian wetlands.

And that is exactly what the flight today on the ARA is aiming to do. Follow this blog to find out how it went.

–Prof. Euan Nisbet, Royal Holloway University of London