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.
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…
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