‘A dream experiment': our Australian icebreaker is on a crucial mission to Antarctica
Onboard are more than 60 scientists and technicians, many on their first research cruise, gingerly gaining their sea legs as the ship navigates multimetre swells and swirling Southern Ocean lows.
After a week or so of travel, they'll push through the sea ice and arrive at their destination for the next 50 days: the remote Denman Glacier ice shelf system in East Antarctica, about 5,000 kilometres south of Australia.
As the planet warms, this is a newly emerging region of concern for Antarctica's contribution to sea-level rise, making this mission crucial for Australia's future and the welfare of the global community.
The 110-kilometre-long Denman Glacier is a vast river of ice draining the East Antarctic ice sheet. It sits on the seafloor in a canyon about 3.5 kilometres below the surface.
As the most northerly ice-shelf system outside the Antarctic peninsula, the Denman Glacier is already one of the fastest retreating glaciers in Australian Antarctic Territory.
If the Denman were to melt entirely, it could contribute about 1.5 metres to global sea level rise, let alone what could be unleashed from the inland ice sheet it holds back.
This voyage has been a long time coming. It's the culmination of about a decade of planning for a dream experiment to investigate the interactions between ice shelf and ocean, from both the marine and terrestrial sides.
Sign up for Guardian Australia's breaking news email
But its genesis began even earlier. Intergovernmental Panel on Climate Change (IPCC) reports in 2007 marked a turning point with the recognition that ice sheets are the problem for global sea-level rise, and that ice shelves are their 'soft underbelly'.
We realised Antarctica was on the move. In 2008, scientists showed that changes in glacier flow have a 'significant if not dominant impact' on the loss of mass from the Antarctic ice sheet.
In 2011, scientists tagged a seal that ended up swimming through a deep trough in the ocean bed near the Denman Glacier, measuring unusually warm water there.
In 2019, a new elevation map of the continental bedrock beneath the Antarctic ice sheet revealed the deepest valley on Earth beneath the Denman Glacier.
For months from the end of 2020, Australian oceanographers tracked a robotic float that travelled underneath the Denman Glacier ice shelf.
Before it disappeared under winter sea ice, the float sent back measurements showing warm water flooding through the deep valley into the ice shelf cavity, enough to rapidly melt the glacier from below.
So this voyage aims to discover not only how vulnerable the Denman Glacier is to the warming ocean, but also the likelihood of it making a larger and faster contribution to sea-level rise during the next few decades.
The Denman Marine Voyage under the Australian Antarctic Program brings together diverse groups of researchers to answer critical questions about the ocean, ice and climate. The onboard science teams – mostly from universities, with a significant number of early-career scientists and PhD students – will cover a broad range of biological, oceanographic, geological and atmospheric research.
As an oceanographer, perhaps what I'm most excited about is the prospect to be measuring the properties of seawater – from both underneath the glacier and over the continental shelf – all at the same time, in a region where few observations have been collected before.
In January, as part of the Denman Terrestrial Campaign from the land side, a string of moored sensors was lowered through a hole in the floating ice shelf and left hanging in a deep underwater canyon near the grounding line of a glacier.
Every day the mooring automatically sends researchers the temperature, salinity and current speed of the water. These data help us track the pathways for deep, warm, salty water to access ice shelves, where it can drive rapid melting.
And now, with the RSV Nuyina moving into position to take simultaneous measurements right in front of the glacier, we should have the vital link that connects the warm flows we detect just offshore in the ocean to what's under the ice shelves.
The only way to get information like this is to be there. With it, we can refine our projections and better understand the hazard that Antarctica presents to our coastlines from the global sea-level rise we can expect – or avoid – this century.
Prof Nathan Bindoff leads the Australian Antarctic Program Partnership, based in the Institute for Marine and Antarctic Studies at the University of Tasmania
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Time Out
2 days ago
- Time Out
Superman
Even those cinemagoers who have grumbled about the preponderance of superhero origin stories – and I'm guilty there – might feel a touch of remorse watching writer-director James Gunn's puckish and political (but wildly overstuffed) blockbuster skip merrily past all the basics of DC's most righteous figure. The Guardians of the Galaxy man, probably mindful of the many Super-movies that have come before his, races through Kal-El's origins in a handful of captions over the opening frames: an Antarctic vista into which a battered and vulnerable Superman (David Corenswet) is hurled after his first defeat in battle over the skies of Metropolis. In those few sentences, establishing the existence of metahumans on Earth and the arrival of Superman from the planet Krypton 30 years prior, this DC reboot skips jauntily past the entire plot of Richard Donner's 1978 classic. So, there's no orientation, none of the scene-setting Smallville stuff with Jonathan and Martha Kent (though they do get a touching later scene). We're not getting those early flirtations with girlfriend Lois Lane (the impressive Rachel Brosnahan) either, or even Clark Kent learning how to use The Daily Planet 's nifty-looking CMS. In fact, we're not getting much of Clark Kent at the most in medias res -iest bit of storytelling imaginable, a gambit that feels more and more misguided as the movie slips deeper into generic superhero terrain in a packed but muddled second half. A giant chasm is carving its way towards Metropolis? Superman is being washed towards a black hole on some kind of quantum waterway? After a while you genuinely start craving a scene where it's just Clark and Lois enjoying a quiet date night. That's surely closer to the heart of this franchise than this torrent of identikit dust-ups. Sparky superdog Krypto will not be for everyone Instead, his umpteenth attempt to get DC's superhero universe airborne throws in team-ups with Green Lantern (Nathan Fillion), Hawkgirl (Isabela Merced), and someone called Mister Terrific (House 's Edi Gathegi, getting the coolest stuff to do here), plus a pair of superbads with shades of Zod's sidekicks, and a bunch of super robots, not to mention the odd giant monster and more than a few falling skyscrapers. The story cedes the floor to the villain: Lex Luthor, played by Nicholas Hoult as an alpha tech man-baby with a pathological need to do away with his Kryptonite foe. He has Supes dancing to his tune throughout, turning the US government and the public against him, and using portals to ship his adversaries to his own interdimensional prison. Ya- awn. On the upside, there's Superman himself. David Corenswet, talented-spotted by Gunn playing Pearl 's creepy projectionist, makes the best Man of Steel since Christopher Reeve, a lovely balance of sweetness, strength and self-doubt bubbling beneath the surface. Like a walking Athena poster, he's born to cradle a baby in his bulging arms. This being a James Gunn movie, he gets a green alien one with a funny face. Its fate makes a cute interlude in one of the (very) many VFX-drenched action sequences. And I enjoyed sparky superdog Krypto! A mundane-looking white pooch, he's a sidekick whose lack of proper training and licky nature makes him a menace to foes and friends alike. Admittedly, he won't be for everyone. Best of all, Gunn never shies away from the political optics of this immigrant hero and his zeitgeisty nemesis, a billionaire megalomaniac adept at manipulating talk shows and social media discourse alike. Luthor even gets his own troll farm staffed by rabid typing monkeys trying to make the hashtag 'Supershit' stick online. (Fox News went with 'Superwoke' instead.) A Superman movie that starts with this immigrant saving an unarmed, possibly Palestinian-coded populace from a neighbouring despot is more than honouring the spirit of Jerry Siegel and Joe Shuster's creation. For Gunn, who has injected superhero movies with a winningly irreverence since his R-rated indie Super, ridding the DCEU of its bombast and self-seriousness is a step in right direction. Whether, like his alien hero, he can arrest the march of time and reinvigorate this tired genre is another matter. In cinemas worldwide Fri Jul 11.
Time Out
4 days ago
- Time Out
Double trouble! Two meteor showers are set to light up Australia's skies just days apart
If there's one thing that'll get Aussies braving the winter chill, it's the allure of a rare celestial event. From magical meteor showers to unexpected auroras, we've had our fair share of cosmic wonders this year – and now, there's a doubleheader set to grace our night skies at the end of this month. In an extremely rare alignment last year, the Delta Aquarids and the Alpha Capricornids meteor showers peaked on the very same night. This year, the double celestial act will happen just days apart – with the Delta Aquarids lighting up the skies on July 28 and the Alpha Capricornids following on July 30. Here's when and how to see the shooting star shows. When to see the Delta Aquariids and Alpha Capricornids in Australia? Late July is set to deliver a cosmic double act, with two meteor showers lighting up Australian skies just days apart. The Delta Aquariids will peak first on Monday, July 28, with the Alpha Capricornids shower reaching their brightest on Wednesday, July 30. According to Associate Professor Devika Kamath from Macquarie University's School of Mathematical and Physical Sciences, the best viewing window is between midnight and 4am (AEST) from July 28 to 31, when both showers are active and the moon is mercifully out of the way. What can you expect to see on the night? At its absolute peak on July 28, the Delta Aquariids could produce up to a whopping 20 shooting stars per hour (given the sky is totally dark and clear). Although fainter, the Alpha Capricornids meteor shower is famous for producing impressively bright fireballs, and you can expect to see two to five meteors per hour – even in areas with light pollution. How to see the double meteor shower in Australia? To witness this cosmic spectacle, it helps to have a little bit of astronomical know-how. The Southern Delta Aquariids appear to radiate from the constellation Aquarius, while the Alpha Capricornids originate from Capricornus. You can use a stargazing app like Stellarium or an online sky chart to find these constellations in your local sky. These tools can help you pinpoint the meteor radiants and plan the perfect viewing spot. Professor Kamath adds, 'In the early evening, the radiants (the points where meteors appear to originate) rise in the northeast. By midnight, they're high in the northern sky, and by pre-dawn, they drift toward the northwest. Scanning this arc will maximise your chances of catching long, dramatic trails.' 🔮
The Guardian
7 days ago
- The Guardian
How to reduce your food footprint: if it's better for you, it's better for the planet
Food production globally accounts for nearly 30% of greenhouse gas emissions, with the average Australian diet contributing more than 3kg of Co2 per person per day. And what's worse, we waste about 35% of the food we bring home. If we keep this up, it has been estimated the already unsustainable environmental cost of the food system will nearly double by 2050. Calculating the precise impact your individual food choices have on the environment isn't simple, but research suggests the actions we can take to bring that impact down are – and they aren't just better for the environment, they're better for our health too. A 2021 CSIRO study found that sticking to its healthy eating guidelines while choosing lower-carbon options could reduce the climate impact of our diets by as much as 42%. Another released last year, which conducted life-cycle assessments on more than 60 thousand products available on Australian shelves, found that switching to lower-emission options within similar categories could bring our food footprints down by an impressive 71%. Prof Simone Pettigrew, program director of food policy at the George Institute for Global Health and an author of the latter study, says: 'There's four biggies that sit at the top of the list for being the least sustainable: traditional red meats, dairy products, and then to a lesser extent – but perhaps more upsettingly – coffee and chocolate.' Consumers, she says, can make a 'massive, massive difference' to the sustainability of their entire food basket simply by limiting or switching out those items. In practical terms this might look like choosing poultry, seafood or kangaroo instead of lamb or pork, switching dairy milk for plant-based options, drinking just one less coffee a day or choosing sweet treats with low or no cocoa content. Even if we can do that some of the time, the difference can be significant, according to Pettigrew. When it comes to carbohydrates and fresh produce, Pettigrew says a solid rule of thumb is the better it is for you, the better it probably is for the planet. Choosing fresh fruits and vegetables to snack on rather than processed biscuits or bars, for example, will dramatically reduce your diet's carbon footprint. And while there are production and processing differences between more nutritionally similar items such as pasta and rice, Pettigrew says overall they are largely comparable in terms of sustainability. 'Anything that is plant based is going to be much less environmentally costly than anything animal based. 'We understand it's hard for consumers to make really big changes in one hit, but it is relatively easy to make small incremental ones.' If you already eat a healthy, plant-rich diet, limit your ultra-processed food intake and are keeping your coffee and chocolate habits in check, you've made a great start. Beyond that, Dr Lilly Lim-Camacho, principal research scientist with CSIRO Agriculture and Food, says one of the most helpful things consumers can do to maximise these gains is to 'shop with intent'. Food waste accounts for more than a third of all household waste, so only purchasing what you need combined with small efforts such as 'learning how to use up leftover veggies in the crisper' and resisting impulse buying will not only make your diet significantly more sustainable, but healthier and more economical too. She urges people to also keep in mind that wasting unhealthy food is doubly bad. 'Not only do discretionary foods create more emissions, our bodies don't actually need them.' Those emissions are essentially being wasted regardless of whether you consume the food or not, she suggests. If you'd like to take things a step further, apps such as ecoSwitch, developed by the George Institute, get into the nitty gritty of comparing the carbon ratings associated with more specific items. This can help if you want to know, for example, which brand of tinned tomatoes or tofu is best. The George Institute study found that opting for near identical but lower-impact options alone could bring your food footprint down by 26%. Neither Pettigrew nor Lim-Camacho want to take the fun out of food or expect consumers to forgo the odd burger or chocolate ice-cream, but agree that by prioritising our health we will naturally make better choices for the planet, and vice versa. 'It's a win-win,' says Pettigrew. 'There is always going to be an environmental cost to our food. But it's important for people to know that you actually can make an enormous difference if you want to.'
