The wind turbines of Scott Base

“Fuel is life in Antarctica,” Jonathan Leitch told me at Scott Base last month. Leitch is in charge of asset management at the permanent New Zealand station that sits near the end of Hut Point Peninsula on Ross Island. This volcanic island, dominated by Mt Erebus, is the most populated part of the frozen continent: Scott Base can sleep up to 85 people, and at the American McMurdo Station, just over the hill, the summer population can reach more than 1200.

For decades, it’s been fossil fuel that has provided the heat to keep people alive here at latitude 77° 51′, where temperatures hover around freezing point in summer and drop to minus 50°C in winter. It powers the aeroplanes, helicopters, Hägglunds and skidoos that take scientists and their gear into remote field camps.

It has powered the reverse-osmosis plants that turn seawater into drinking water, the waste water plants that treat the sewage, and the hitching rails that keep vehicles warm in the cold air. No wonder, then, that most of the freight (by weight) that is shipped to Ross Island is fuel for generators, space heaters and vehicles.

But things are changing. In a new project initiated by Antarctica New Zealand, up to 60% of Ross Island’s electrical energy is now provided by wind power. In early 2010, Meridian Energy installed three 330kW wind turbines – locally referred to as “the three sisters” – on Crater Hill behind Scott Base. Now they sit on the horizon between Scott Base and McMurdo, their gentle whirr adding to the soundscape of helicopters, monster trucks and the occasional seal roar.

“It’s been a huge success,” says Leitch. When the wind is blowing, the turbines provide all Scott Base’s electrical energy, with excess sent to McMurdo Station. When the wind stops, McMurdo’s generators provide electrical energy to Scott Base. “There’s been a change in thinking,” says Leitch. “Scott Base and McMurdo Station used to be run separately, but for generation and consumption of power we’re now one.” It’s no longer the New Zealand network and the United States network: it’s the Ross Island network.

Ross Island has the same issues with fossil fuel as New Zealand – it’s expensive, it has to be shipped from the northern hemisphere, and it releases CO2 into the atmosphere. But because of Antarctica’s remote location and pristine environment, these problems are compounded. In the heroic age, before the Antarctic Treaty protected the continent’s wildlife, explorers supplemented imported fuel by burning seal or penguin blubber. When Sir Edmund Hillary drove from Scott Base to the South Pole in 1958, he cooked food and heated his tent with paraffin and kerosene and powered his Massey Ferguson tractor with petrol.

These days, aviation fuel, which does not begin to congeal until minus 50°C, is used for Ross Island’s main generators and aircraft. Portable field generators and vehicles run on Mogas, a low octane unleaded petrol. By allowing Scott Base to shut down its main generators, the wind farm has so far resulted in collective United States and New Zealand fuel savings of more than 450,000 litres a year. But it’s not Ross Island’s first attempt at an alternative energy source.

In the summer of 1962, the Americans installed a 1.8MW nuclear power station, run on a mix of uranium-235 and uranium-238, at McMurdo. But the McMurdo reactor – dubbed “nukey-poo” by its New Zealand neighbours – was plagued with problems and in 1967 plans to add nuclear power stations at the American bases at Byrd Station and the South Pole were shelved. After a 1972 inspection revealed a crack in a water tank used to provide radiation shielding, the McMurdo reactor was decommissioned.

The dismantled reactor, along with more than 70 tonnes of soil contaminated with radioactive isotopes such as caesium-137, was removed and shipped back to the United States via Lyttelton.

That was Antarctica’s only foray into nuclear power, but Ross Island’s wind turbines are not the first on the continent. At Australia’s Mawson Station, in East Antarctica, two wind turbines supply up to 70% of the station’s electrical energy. Small wind turbines power some remote field stations. And in the Antarctic summer, solar power provides energy to some field camps and monitoring stations.

Mogas generators are still used in most short-term field camps, but Leitch says Antarctica New Zealand’s plan is to make the portable field units more energy-efficient. The new generation of huts will have better insulation, glass doors to capture the solar gain of the 24-hour summer sunshine, and either more efficient diesel generators or solar or wind power generators.

Fossil fuel still plays a big role in Antarctica. The fuel tanker is expected to arrive at McMurdo this month. An icebreaker will travel ahead of it, cutting a channel through the sea ice to let the tanker through to the ice pier at McMurdo. Once it arrives it will take two days to pump the fuel from the ship to the tanks at the base of Observation Hill above McMurdo.

But dependence on fossil fuel is changing. With some more turbines, along with new plant to store water and energy when the wind farm is operating at full capacity, and a switch to electrical boilers and cookers, wind could one day soon supply all the island’s electrical needs.

Rebecca Priestley travelled to Scott Base on Antarctica New Zealand’s media programme.

First published in the Listener, 7 January 2012.

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Ernest Shackleton’s 100-year-old whisky

When Ernest Shackleton was ordering provisions for his 1907 expedition to Antarctica, he made it clear that along with the requisite tins of herrings, mulligatawny soup, gooseberry jam and marmalade, he and his men required a supply of whisky. Not just any whisky, but a fine Highland malt. Twenty-five cases of it.

When Shackleton left Antarctica in 1909, after reaching 88° 23′ south – the closest anyone had been to the South Pole – he left some of that whisky behind. Now, thanks to an international team of conservators and chemists, we know what the whisky looked like and how it was made. And whisky-lovers willing to pay £100 (NZ$200) for a bottle of the replica whisky that went on sale last month will know just what it tasted like.

Shackleton’s whisky had been forgotten until 2006, when conservators from the Antarctic Heritage Trust (AHT) discovered the corners of five frozen crates beneath Shackleton’s hut at Cape Royds. After three seasons during which conservators painstakingly chipped away at a century of ice accumulation in the crawl space beneath the hut, three of the crates labelled “Mackinlay’s Rare Old Highland Whisky” were removed last year. One crate was flown to Canterbury Museum to be thawed and examined. According to AHT conservator Lizzie Meek, it looked more like a 40kg block of ice than a crate of whisky.

“Over the years, water had gotten into the crate and filled up every nook and cranny and the whole thing was a big iceblock,” says Meek. The first sign that there were bottles inside came when the crate went through airport security at Christchurch. “The bottles showed up on x-ray and we could clearly see liquid inside some of them.”

At Canterbury Museum, in a specially prepared cold room, the crate, which had spent 100 years at temperatures down to minus 40°C, was gradually brought up to 4°C to thaw. Once the ice, speckled with lumps of scoria, was gone, conservators recovered 11 bottles of whisky, carefully wrapped in tissue paper and protective straw. Meek describes them as being in “fantastic condition.”

The AHT decided that as well as preserving the whisky crates and bottles, it had an opportunity to find out more about what was inside them. The initial plan was for a small sample of liquid to be removed to find out more about historic whisky making, but when the current owner of Whyte & Mackay, the parent company of Mackinlay’s, got involved, the project took a grander turn. Three bottles of whisky were transported to Whyte & Mackay in Scotland for analysis by the distillery’s chemists. The bottles travelled in style, in a high-tech chilly bin filled with ice and gel packs, handcuffed to the arm of Whyte & Mackay master blender Richard Paterson, on the private jet of Whyte & Mackay owner Vijay Mallya.

In Scotland, chemists at Whyte & Mackay’s Invergordon distillery, with input from analysts at the Scotch Whisky Research Institute in Edinburgh, subjected the whisky to a battery of tests. Under sterile conditions, a sampling needle was passed through the cork of each bottle to remove a 100ml sample.

After the liquid was analysed for variables such as microbiology, alcohol levels, pH and acidity, samples were sent to outside laboratories for further analysis. After the mass spectrometers and gas and liquid chromotographs had done their work – including radiocarbon-dating the whisky and measuring levels of ethyl esters, phenols, cations, anions, sugars and metals – it was up to a panel of 15 expert “noses” from the Scotch Whisky Research Institute to profile the whisky’s flavour. Using a fixed vocabulary, they scored the whisky as having a balance of “peaty, mature woody, sweet, dried fruit and spicy” aromas. (That’s not too bad for a scale that also includes such less desirable descriptors as “goat” and “stagnant drains”.)

The first thing the analysts noted, in a paper recently published in the Journal of the Institute of Brewing, was how well the whisky was preserved. Whisky ages in the cask, not in the bottle, and temperatures at Cape Royds had preserved the whisky in its 1907 state. Analysis revealed a well-preserved malt whisky of 47.3% alcohol by volume – high enough to stop the alcohol freezing – made with water from Loch Ness and using peat from the Orkney Isles.

When distilled, whisky is clear, like gin, with the colour coming over time from the wooden barrels in which the spirit is aged. Analysis of compounds formed from the breakdown of lignins from the cask maturation of the whisky, along with the levels of fructose and sucrose, revealed a whisky matured for five to 10 years in sherry casks made from American Oak.

Paterson then attempted to reconstruct Shackleton’s 1907 whisky as a blend of modern whiskies. The result, according to whisky expert and writer Dave Broom, who has tasted both the 100-year-old whisky and the replica, is “bang on”. A percentage of global sales from the replica whisky goes to the AHT, which stands to raise $500,000 for Antarctic conservation projects. The bottles that travelled to Scotland will be back in New Zealand soon, and will be returned to the crate, which will be resealed and returned to its place in Antarctica, at Shackleton’s hut. As for the other two crates found beneath the hut, the label on the side says they are brandy, and word is they are next in line for conservation.

First published in The Listener, 29 October 2011

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Antarctica 2014: a few words and some pictures (more to come)

The first time I visited Antarctica I was in the company of a poet (and essayist and novelist), Alice Miller. We were there at the Invitation of Antarctica New Zealand, on their media and artists’ programme, and were hosted and generally looked after by their then communications manager Matt Vance, who was our designated “on-ice escort”, a title that always made Alice and me giggle.

We did a fair bit of giggling those 12 days in Antarctica. And talking. And walking. Even a bit of crying one time. We bonded over the weirdness of Antarctica and the fact that we were even there. As a science writer, I spent much of each day in science mode – joining marine biologists or glaciologists in their daily field excursions, interviewing scientists about their work, visiting the Crary Lab at McMurdo Station, writing pages of notes about science and the frozen world I could see around me. But I also spent a lot of time with Alice, just being a writer.

As a writer it was easy to sit apart, to observe, to reflect. I wasn’t on holiday, but it didn’t feel like work either. No one was paying me to be in Antarctica. It was an experience, an incredible experience that I couldn’t help but write about. The sun shone every day – and all day – until the day we were due to fly home. It clouded over, meaning the plane scheduled to fly us home could not land, and we gained an unexpected four-day extension to our visit.

At the end of my visit I wrote that I loved this place, that I wanted to come back.

“I’m already thinking of ways to get back there. I could continue with my earth sciences study and turn my honours degree into a Masters! If that didn’t cut it I could do another PhD! I could offer my services as embedded journalist cum field assistant on a major science project!”.

I came to my senses (somewhat) once I got home and got on with my life in New Zealand, which included getting an academic position at Victoria University. Late last year I visited Antarctica to film some lectures for a new online course about Antarctica. I’m running a module on Antarctica science history, and my colleague Cliff Atkins is running a module on geology and paleoclimate. We were linked to event K001-B, a geology project in the Friis Hills led by Tim Naish from Victoria University’s Antarctica Research Centre and Richard Levy from GNS Science.

A friend told me recently that I often exhibit signs of FOMO: fear of missing out. I do. I sometimes get so scared of missing out on stuff that I do too much, or try to do too much, and get over-stimulated and flustered. In Antarctica, without my poet friend to empathise with every moment of weirdness I experienced, I had to remind myself to take time out: after the first two days of rushing around I found I could replenish myself by stealing away to my room, for some introvert time to think and reflect and remember why I’m here.

I felt quite discombobulated for the first couple of days: I’d left family in Wellington, including a seven year old son who begged me not to go to Antarctica, then I’d spent the day before my flight south caring for my dying father in Christchurch. So to get on a Hercules and fly seven and a half hours to Antarctica felt surreal in quite an uncomfortable way. Things got better when I threw myself into my work.

I have different things to say about this trip, things that require a bit more thinking than my first wide-eyed visit to Antarctica. I’ve already written a few pieces for The Listener, which I’ve posted here, here and here, but while I’m working on a longer more personal story, here are some pictures of Antarctica.

The compulsory we-just-arrived-in-Antarctica-and-can't-stop-smiling photo. Check out our fancy ride.

The compulsory we-just-arrived-in-Antarctica-and-can’t-stop-smiling photo. Check out our fancy ride.

IMG_7154 PigIMG_7158 Offload hereIMG_7184 Visitor parkingIMG_7164 Taxi of science2

Richard Levy with Erebus and pen #1.

Richard Levy with Erebus and pen #1.

Richard Levy with Erebus and pen #2. Seriously, he spent the day like this.

Richard Levy with Erebus and pen #2. Seriously, he spent the day like this, supervising the many helicopter trips it took to take the K001 team and all the gear into the Friis Hills campsite. 


In helicopter from Scott Base to Friis Hill we got a great view of the Royal Society Range: peaks are about 4000 metres high.

In helicopter from Scott Base to Friis Hill we got a great view of the Royal Society Range: peaks are about 4000 metres high.

The distinctive layer cake look of the Beacon Supergroup, sandstones and dolerites.

The distinctive layer cake look of the Beacon Supergroup, sandstones and dolerites.

My tent!

My tent!

Campsite after snowfall (not a common event in the Dry Valleys region).

Campsite after snowfall (not a common event in the Dry Valleys region).

The Polar Haven, where we cooked and ate. That's Nick Golledge cleaning his teeth outside.

The Polar Haven, where we cooked and ate. That’s Nick Golledge cleaning his teeth outside.

I film Cliff talking to Nick Golledge about glaciers. Thanks to Adam Lewis for taking the photo!

I film Cliff talking to Nick Golledge about glaciers. Thanks to Adam Lewis for taking the photo!

Armoured surface. I love this. All the fine stuff has been blown away by the winds.

Armoured surface. I love this. All the fine stuff has been blown away by the winds.

The wind does these crazy things to the rocks.

The wind does these crazy things to the rocks.

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A different kind of cold

They say for every 10°C drop in temperature, it’s a “different kind of cold”. The -20°C I experienced camping at Friis Hills in Antarctica was certainly new for me, but the geologists I was with seemed unconcerned: their minds were on another Antarctica. They were there to investigate times in our planet’s history when the continent was a lot warmer than it is today.

The approach to Friis Hills. Our campsite was on top of that plateau.

The approach to Friis Hills. Our campsite was on top of that plateau.

Friis Hills is a 1300m-high, ice-free plateau in the Dry Valleys region of the Transantarctic Mountains, about 100km from Scott Base. The views – steep-sided mountains, enormous glaciers, a glimpse of the polar plateau – are awesome, but we weren’t there for the scenery. Our field party, led by Professor Tim Naish from Victoria University’s Antarctic Research Centre and Richard Levy from GNS Science, was focused on the sediments and glacial deposits beneath our boots.

View of where the Taylor Glacier meets the Ferrar Glacier.

View of where the Taylor Glacier meets the Ferrar Glacier.

Adam Lewis, a glacial geomorph­ologist from North Dakota State University, had already spent five field seasons at Friis Hills. On his first visit, he and his colleague found “fossil tundra everywhere we looked”. The leaves, insects, pollen and seeds hinted at a climate with summer air temperatures some 20°C warmer than today. Lewis and his students have since identified a sequence of glacial moraines interspersed with life-supporting water bodies – ponds, marshes and small lakes – created by glacial meltwaters. It’s clear that the landscape was created by a series of advancing and retreating glaciers, but what’s remarkable about the Friis Hills landscape, and what makes it so interesting to geologists, is that it was created 14-20 million years ago and preserved intact since then. After this time, the climate changed: air temperatures became colder, rain stopped falling and the water became locked up in glacial ice – plants could no longer grow here. At least that’s what the geomorphologists believe.

And then ... we found these tiny fossils in the sediments from the drill site. I'm going to call them beech leaves, cos scientists are arguing about the Latin name these days.

And then … we found these tiny and perfect southern beech leaves in the sediments from the drill site.

Sedimentologists such as Naish and Levy have found evidence of a warm period three to five million years ago. Ross Sea sediment cores from the Andrill project revealed that “the ocean warmed up, there was no Ross Ice Shelf, the West Antarctic Ice Sheet collapsed and the ocean was too warm to support sea ice”, says Naish. It’s puzzling that at the same time as the ocean was warming, the mountains seem to have remained cold and frozen. These contradictory pieces of paleoclimate evidence are part of a 30-year debate over what happened to the massive East Antarctic Ice Sheet three to five million years ago: did it collapse or remain intact? Sediments that preserve information about land-based climate from three to five million years ago are rare – but there are 14-20 million-year-old deposits in both marine sediments and Friis Hills. “That these deposits are so well preserved at Friis Hills implies that much of the high interior East Antarctic Ice Sheet survived the global warmth of the Pliocene, unlike the West Antarctic Ice sheet, which was attacked by warming oceans,” says Levy. The team working at Friis Hills last December took sediment cores and did acoustic surveys across old lake beds to get a more detailed picture of what was going on. Correlating this land-based evidence with existing drill-core evidence – and determining the likely temperature gradient from mountain to sea – will help reveal what happened to the East Antarctic Ice Sheet over past periods of global warming.

Warren Dickinson setting up the drill. Drilling in permafrost is no easy task.

Warren Dickinson setting up the drill. Drilling in permafrost is no easy task.

Andrew Gorman monitoring the seismic line.

Andrew Gorman monitoring the seismic line.

Richard Levy and Nick Golledge manning the hammer seismic line.

Richard Levy and Nick Golledge manning the hammer seismic line.

The greenhouse gases we’re pumping into the atmosphere have raised atmospheric CO2 levels to 400 parts per million. The last time CO2 levels were this high was three to five million years ago. Naish says we have a good understanding of what was happening in the oceans at that time, but understanding what was happening on land is “important for getting to the nub of the controversy over how warm Antarctica was three to five million years ago”.

Geographically appropriate reading: At the Mountains of Madness,

Geographically appropriate reading: At the Mountains of Madness,

K001 at Friis Hills: Andrew Gorman, Richard Levy, Christoph Kraus, Nick Golledge, Tim Naish, Adam Lewis, Rebecca Priestley, Warren Dickinson and Cliff Atkins.

K001 at Friis Hills: Andrew Gorman, Richard Levy, Christoph Kraus, Nick Golledge, Tim Naish, Adam Lewis, Rebecca Priestley, Warren Dickinson and Cliff Atkins.

This story was originally published in The Listener.

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Scott’s Hut: revisited

Few people conjuring up the “most comfortable dwelling place imaginable” are likely to picture a wooden shelter on an island off the coldest continent on Earth. But that’s how Antarctic explorer Robert Falcon Scott described the hut at Cape Evans that was the base for his 1910-13 Terra Nova expedition.

The hut is nestled below a small volcanic hill on a long stretch of black sand. I’ve been there twice, when it looked like a building site in 2011, and again on a sunny day last December. On my second visit, seals lay on the sea ice in front of the newly restored structure and sun glinted off the ice cliffs of the nearby Barne Glacier.

The New Zealand Antarctic Heritage Trust recently announced the completion of 10 years of intensive work to save three historic buildings on Ross Island. As well as the hut at Cape Evans, it has been working on the Discovery Hut from Scott’s 1901-04 expedition, at Hut Point, and the hut at Cape Royds, built for Ernest Shackleton’s 1907-09 Nimrod expedition.

On my first Cape Evans hut visit, many of the artefacts had been removed while carpenters repaired the walls, floors and roof. This time, the hut contents had been returned, and Lizzie Meek, a specialist paper conservator and the trust’s programme manager for artefacts, showed me around. In Scott’s “zone of command” was the table – now home to a stuffed emperor penguin and a 1908 edition of the Illustrated London News – where Edward Wilson made his enduring biological illustrations. In a dark corner nearby, Edward Atkinson had incubated his moulds and parasites. My favourite space, though, was the small workbench and array of test tubes, sample jars and Bunsen burner stands of biologist Edward Nelson, lit by sunshine through a murky window. This was where the young scientist preserved marine specimens – fish, krill, starfish and more – as part of his search for new species and an understanding of the Antarctic food chain.

Inside Scott's newly restored hut at Cape Evans.

Inside Scott’s newly restored hut at Cape Evans.

Trust executive director Nigel Watson describes the three restored huts as “fantastic remnants of humans’ first contact with the continent”. The genesis of the conservation project, he says, “was the fact that we were in great danger of losing them”. When the on-site work began in 2004, snow and ice were building up around, under and sometimes inside the huts, damaging the structures and threatening their contents.

“We now have three buildings that are structurally sound and watertight with a very different feel – they are drier and lighter and the humidity is reduced. It’s a much better environment for the collection.”

As well as heritage carpenters, the trust team has included specialists in textile, paper and metal conservation: in total, 62 experts from 11 countries have visited Antarctica to work on the project, often spending months on-site, sleeping in tents and popping 25km back to Scott Base for the occasional shower. “It became known as the most exciting conservation project in the world,” says Watson, “so it attracted top heritage conservation talent.”

Some of the most exciting discoveries were three intact crates of “Mackinlay’s Rare Old Highland Malt Whisky” found encased in ice beneath Shackleton’s hut, a notebook that belonged to surgeon, zoologist and photographer George Murray Levick found buried in dirt at Cape Evans and a small box of 22 cellulose nitrate negatives found in Herbert Ponting’s darkroom in the Terra Nova hut.

But most of the 18,202 items catalogued and conserved are more mundane: food, tools, clothing and other personal items that were not precious enough to be taken home on the return voyages.

The trust’s conservation treatments involved “removal of degradation products followed by chemical treatment to either slow, or in some cases reverse, the deterioration”, said Meek when we spoke again last week. Metal items would go through corrosion removal, followed by a chemical stabilisation treatment, then application of an oxygen and moisture barrier to prevent further corrosion. Treatment of paper items often involved washing “to dissolve harmful acids and salts and to help the fibres to reknit, often resulting in the paper having a stronger cohesion”.

As a result of the project, the trust has become the world leader in cold-climate heritage conservation. Next summer, its skills will be applied to a new challenge. The Ross Island huts are the “jewels in the crown”, says Watson, but there are other historic buildings needing attention. With logistics support from Antarctica New Zealand, programme managers Al Fastier and Meek will be part of a small team heading to Cape Adare, an exposed site more than 700km north of Scott Base. The two Cape Adare huts, remnants of an 1898-1900 British expedition led by Carsten Borchgrevink, “are not only the first buildings on the continent”, says Watson, but also “the only example of humanity’s first buildings on any continent on Earth”.

Inside Scott's hut.

Inside Scott’s hut.

The three-year restoration effort will involve building repairs and the removal, conservation and return of about 1100 objects. Compared with the relatively sheltered hut sites on Ross Island, Cape Adare is “a very remote and challenging place to work in”, says Watson. “It’s set among the world’s biggest Adélie penguin colony on an exposed spit of land and these little wooden buildings are just perched there, defying the elements.”

Meek looks forward to the challenge. “But I’m also looking forward to going back to the Ross Island huts and seeing them with fresh eyes. After so many years of working on them, to be able to step inside and look around to see what we have accomplished will be amazing.”

If you can find your way to Antarctica, you’ll need a permit to visit any of the Ross Island huts, which are each in an Antarctic Specially Protected Area. But there’s an easier way to see them: the trust has partnered with Google to offer Street View walkthroughs of each of the dwellings, available via Google Earth or through the trust’s website at

This story was first published in The Listener at

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Breathless in Antarctica

Camping in Antarctica last December, I noticed that even though it was extremely cold, -10°C to -20°C, our exhalations didn’t make visible clouds. When the helicopter landed to pick us up, though, our breath appeared as dense white clouds. Why was this?

Adam Lewis and Tim Naish before heading off for Friis Hills: Adam demonstrating the visible breath around helicopters phenomenon.

Adam Lewis and Tim Naish before heading off for Friis Hills: Adam demonstrating the visible breath around helicopters phenomenon.

Adam Lewis, a glacial geologist from North Dakota State University, initially made this observation while we were walking in the Friis Hills, a 1300m-high plateau about 50km up the Taylor Valley in the Dry Valleys region of Antarctica. Part of a group of geologists led by Tim Naish from Victoria University’s Antarctic Research Centre and Richard Levy from GNS Science, we speculated as to what extent the lack of visible breath had to do with the dryness of the air and the lack of cloud condensation nuclei.

The clouds we expect to see when someone exhales on a cold day are made from tiny droplets of liquid water. These out-breaths create a visible cloud for the same reason clouds form in the sky. Air – which is primarily composed of nitrogen and oxygen – also contains a small amount of gaseous water, and the warmer the air, the more water gas it’s capable of holding. When air cools, it can hold less water gas, and some of the gas will condense out of the air and start to form droplets of liquid water. In sufficient quantities, these droplets can form a visible cloud. Droplets of liquid water tend to form around condensation nuclei, tiny particles of sea salt, dust, clay or soot.

We started talking about the invisible breath issue when Adam Lewis took us for a walk over the Friis Hills.

We started talking about the invisible breath issue when Adam Lewis took us for a walk over the Friis Hills.

Back in Wellington, I asked MetService’s Erick Brenstrum why our ­Antarctic breath-clouds were different from those we experience in New Zealand.

“When you breathe out, you’re breathing warm air with high water content,” he explained. In the Friis Hills, the warm, moist breath coming from our lungs would have mixed with the surrounding air, which had a temperature of about -10°C and perhaps only 10% humidity (compared with the 60-90% humidity typical of New Zealand). As warm air from our lungs mixes with the cold air outside, “it cools, and wants to make a cloud. But if the air it’s mixing with is incredibly dry, the water gas is never going to reach a concentration where it forms a liquid and makes a cloud. So if you’re in an incredibly dry environment, even when you breathe out high-humidity air, you don’t get a cloud.”

So what difference did the proximity of the helicopter make? “When you burn fuel in an engine, one of the by-products is water gas. So it could be that locally, under and around the helicopter, you’re suddenly getting a large quantity of water gas. So when you breathe out moist air, you’re able to reach 100% humidity and you get a little cloud.”

Condensation nuclei play a part too. “It’s highly likely that pollutants from the burning of the fuel would act as condensation nuclei. It’s also likely there would be some on the ground, thrown up by rotor action.”

That said, a definitive answer to this question would demand controlled testing and repeatable results. Perhaps a good reason to return to Antarctica?

This story was originally published in The Listener


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