Tag Archives for air

Engineers have built machines to scrub CO₂ from the air. But will it halt climate change?



Climeworks

Deanna D’Alessandro, University of Sydney

On Wednesday this week, the concentration of carbon dioxide in the atmosphere was measured at at 415 parts per million (ppm). The level is the highest in human history, and is growing each year.

Amid all the focus on emissions reduction, the Intergovernmental Panel on Climate Change (IPCC) says it will not be enough to avoid dangerous levels of global warming. The world must actively remove historical CO₂ already in the atmosphere – a process often described as “negative emissions”.

CO₂ removal can be done in two ways. The first is by enhancing carbon storage in natural ecosystems, such as planting more forests or storing more carbon in soil. The second is by using direct air capture (DAC) technology that strips CO₂ from the ambient air, then either stores it underground or turns it into products.

US research published last week suggested global warming could be slowed with an emergency deployment of a fleet of “CO₂ scrubbers” using DAC technology. However a wartime level of funding from government and business would be needed. So is direct air capture worth the time and money?

Smoke stack with CO2 written in smoke
Direct air capture of CO2 will be needed to address climate change.
Shutterstock

What’s DAC all about?

Direct air capture refers to any mechanical system capturing CO₂ from the atmosphere. Plants operating today use a liquid solvent or solid sorbent to separate CO₂ from other gases.

Swiss company Climeworks operates 15 direct air capture machines across Europe, comprising the world’s first commercial DAC system. The operation is powered by renewable geothermal energy or energy produced by burning waste.

The machines use a fan to draw air into a “collector”, inside which a selective filter captures CO₂. Once the filter is full, the collector is closed and the CO₂ is sequestered underground.



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Canadian company Carbon Engineering uses giant fans to pull air into a tower-like structure. The air passes over a potassium hydroxide solution which chemically binds to the CO₂ molecules, and removes them from the air. The CO₂ is then concentrated, purified and compressed.

Captured CO₂ can be injected into the ground to extract oil, in some cases helping to counteract the emissions produced by burning the oil.

The proponents of the Climeworks and Carbon Engineering technology say their projects are set for large-scale investment and deployment in coming years. Globally, the potential market value of DAC technology could reach US$100bn by 2030, on some estimates.

Artist impression of a DAC facility to be built in Houston, Texas.
Artist impression of a DAC facility to be built in the US state of Texas. If built, it would be the largest of its kind in the world.
Carbon Engineering

Big challenges ahead

Direct air capture faces many hurdles and challenges before it can make a real dent in climate change.

DAC technology is currently expensive, relative to many alternative ways of capturing CO₂, but is expected to become cheaper as the technology scales up. The economic feasibility will be helped by the recent emergence of new carbon markets where negative emissions can be traded.

DAC machines process an enormous volume of air, and as such are very energy-intensive. In fact, research has suggested direct air capture machines could use a quarter of global energy in 2100. However new DAC methods being developed could cut the technology’s energy use.



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While the challenges to direct air capture are great, the technology uses less land and water than other negative emissions technologies such as planting forests or storing CO₂ in soils or oceans.

DAC technology is also increasingly gaining the backing of big business. Microsoft, for example, last year included the technology in its carbon negative plan.

Emissions rising from a coal plant.
Direct air capture is touted as a way to offset emissions from industry and elsewhere.
Shutterstock

Opportunities for Australia

Australia is uniquely positioned to be a world leader in direct air capture. It boasts large areas of land not suitable for growing crops. It has ample sunlight, meaning there is great potential to host DAC facilities powered by solar energy. Australia also has some of the world’s best sites in which to “sequester” or store carbon in underground reservoirs.

Direct air capture is a relatively new concept in Australia. Australian company Southern Green Gas, as well as the CSIRO, are developing solar-powered DAC technologies. The SGG project, with which I am involved, involves modular units potentially deployed in large numbers, including close to sites where captured CO₂ can be used in oil recovery or permanently stored.

If DAC technology can overcome its hurdles, the benefits will extend beyond tackling climate change. It would create a new manufacturing sector and potentially re-employ workers displaced by the decline of fossil fuels.

Red sand and tussocks of grass
Australia has ample sunlight and plenty of non-arable land where DAC facilities could be built.
Shutterstock

Looking ahead

The urgency of removing CO₂ from the atmosphere seems like an enormous challenge. But not acting will bring far greater challenges: more climate and weather extremes, irreversible damage to biodiversity and ecosystems, species extinction and threats to health, food, water and economic growth.

DAC technology undoubtedly faces stiff headwinds. But with the right policy incentives and market drivers, it may be one of a suite of measures that start reversing climate change.



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The Conversation

Deanna D’Alessandro, Professor & ARC Future Fellow, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Air quality near busy Australian roads up to 10 times worse than official figures



FABRIZIO BENSCH/ Reuters

Hugh Forehead, University of Wollongong

Air quality on Australia’s roads matters. On any given day (when we’re not in lockdown) people meet, commute, exercise, shop and walk with children near busy streets. But to date, air quality monitoring at roadsides has been inadequate.

I and my colleagues wanted to change that. Using materials purchased from electronics and hardware stores for around A$150, we built our own air quality monitors.

Our newly published research reveals how our devices detected particulate pollution at busy intersections at levels ten times worse than background levels measured at official air monitoring stations.



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Our open-source design means citizen scientists can make their own devices to measure air quality, and make the data publicly available.

This would provide more valuable data about city traffic pollution, giving people the information they need to protect their health.

Air pollution can have serious health consequences.
Tim Wimborne/Reuters

Particulate matter: a tiny killer

Everyone is exposed to airborne particulate matter emitted by industry, transport and natural sources such as bushfires and dust storms.

Particulate matter from traffic is a mixture of toxic compounds, both solid and liquid. It’s a well-known health hazard, particularly for children, the elderly, pedestrians, cyclists and people working on or near roads.

Particulate matter smaller than 2.5 micrometres in diameter, referred to as PM2.5, is particularly harmful. To put this in context, a human hair is about 100 micrometres in width.

When inhaled, these fine particles can damage heart and brain function, circulation, breathing and the immune and endocrine systems. They have also been linked to cancer and low birth weight in newborns.

Do-it-yourself air monitoring

Highly reliable equipment to measure air quality has traditionally been expensive, and is not deployed widely.

Official air quality monitoring usually takes place open spaces or parks, to provide an averaged, background reading of pollution across a wide area. The monitoring stations are not typically placed at pollution sources, such as power stations or roads.

However there is growing evidence that people travelling outdoors near busy city roads are exposed to high levels of traffic emissions.

An air quality monitor built by the researchers and painted purple, attached to a light pole in Liverpool, Sydney.
Author supplied

Air quality monitors can be bought off the shelf at low cost, but their readings are not always reliable.

So I and other researchers at the University of Wollongong’s SMART Infrastructure Facility made our own monitors. They essentially consist of a sensor, weatherproof housing, a controller and a fan. Anyone with basic electronics knowledge and assembly skills can make and install one. The monitor connects to the internet (we used The Things Network) and the software required to run it and collect the data is available for free here.

The weatherproof housing cost about A$16 to make. It consists of PVC plumbing parts, a few screws and small pieces of fibreglass insect screen, which can be bought at any hardware store.

Sensors can be bought from electronics retailers for little as A$30, but many are not tested, calibrated or overseen by experts and can be inaccurate. We tested three, and chose the Novasense SDS011, which we bought for A$32.

A controller is needed to run the monitor and send data to the internet. We bought ours from an online retailer for under A$60. A fan, needed to circulate air through the housing, was bought from Jaycar for A$14.

Accounting for wiring and a few other parts, our monitors cost under A$150 each to make – ten times cheaper than mid-grade commercial detectors – and produce reasonably accurate results.

What we found

Following community meetings, we deployed our sensors at nine key locations and intersections around Liverpool in Western Sydney, a region which has traditionally suffered from poor air quality.

Our monitors have been in place since March 2018, placed close to pedestrian height on structures such as light poles, shade awnings or walls.



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They have detected roadside measurements of PM2.5 at values of up to 280 micrograms per cubic metre in morning peak traffic. This is more than ten times the readings at the nearest official monitoring station. The severity of the pollution and how long it lasts depends on how bad the traffic is.

These findings are comparable to other studies of busy roads.

Pollution from vehicle emissions can have serious health consequences.
Dean Lewins/AAP

Breathing easier

Our experience of roadside air quality can be improved in a number of ways.

Obviously, exposure to air pollution is worst at peak traffic times, so plan your travel to avoid these times, if possible.

Pollution levels drop quickly with distance from busy roads and can be at near background levels just one block away. So try to detour along quieter back streets or through parks.

Barriers, such as dense roadside vegetation, can shield pedestrians from pollution. Children in prams are more exposed to traffic pollution than adults, as they are closer to the level of vehicle exhaust pipes. Pram covers can reduce infants’ exposure by up to 39%.

Of course, the best way to reduce air pollution from traffic is to have fewer vehicles on our roads, and cleaner fuel and engines.

In the meantime, we hope our low-cost technology will prompt citizen scientists to develop their own sensors, producing the data we need to breathe easy in city streets.



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The Conversation

Hugh Forehead, Research Fellow, University of Wollongong

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Feeling flight shame? Try quitting air travel and catch a sail boat



Regina Maris, the ship activists will sail to a climate conference in Chile.
Sail to the COP

Christiaan De Beukelaer, University of Melbourne

If you’ve caught a long haul flight recently, you generated more carbon emissions than a person living in some developing countries emits in an entire year.

If that fact doesn’t ruffle you, consider this: worldwide, 7.8 billion passengers are expected to travel in 2036 – a near doubling of current numbers. If business as usual continues, one analysis says the aviation sector alone could emit one-quarter of the world’s remaining carbon budget – the amount of carbon dioxide emissions allowed if global temperature rise is to stay below 1.5℃.

The world urgently needs a transport system that allows people to travel around the planet without destroying it.

A group of European climate activists are sending this message to world leaders by sailing, rather than flying, to a United Nations climate conference in Chile in December.

The Sail to the COP initiative follows Greta Thunberg’s high-profile sea voyage to attend last month’s United Nations climate summit in New York. The activists are not arguing global yacht travel is the new normal – in fact therein lies the problem. We need to find viable alternatives to fossil-fuelled air travel, and fast.

Greta Thunberg onboard the racing boat Malizia II in the Atlantic Ocean on her journey to New York last month.
AAP



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Why aviation emissions matter

A study conducted for the European Parliament has warned that if action to reduce flight emissions is further postponed, international aviation may be responsible for 22% of global carbon emissions by 2050 – up from about 2.5% now. This increasing share would occur because aviation emissions are set to grow, while other sectors will emit less.

In Australia, aviation underpins many aspects of business, trade and tourism.

The below image from global flight tracking service Flightradar24 shows the number of planes over Australia at the time of writing.

A screen shot from Flightradar24 showing the flights over Australia at the time of writing.
Flightradar24

Federal government figures show the civil aviation sector, domestic and international, contributed 22 million tonnes of carbon dioxide-equivalent emissions in 2016.

The number of passenger movements from all Australian airports is set to increase by 3.7% a year by 2030-31, to almost 280 million.

To change, start with a jet fuel tax

While airlines are taking some action to cut carbon emissions, such as introducing newer and more fuel efficient aircraft, the measures are not enough to offset the expected growth in passenger numbers. And major technological leaps such as electric aircraft are decades away from commercial reality.

Emissions from international flights cannot easily be attributed to any single country, and no country wants to count them as their own. This means that international civil aviation is not regulated under the Paris Agreement. Instead, responsibility has been delegated to the International Civil Aviation Organisation (ICAO).



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The Sail to the COP initiative is calling for several actions. First, they say jet fuel should be taxed. At present it isn’t – meaning airlines are not paying for their environmental damage. This also puts more sustainable transport alternatives, which do pay tax, at a disadvantage.

Research suggests a global carbon tax on jet fuel would be the most efficient way to achieve climate goals.

But instead, in 2016 ICAO established a global scheme for carbon offsetting in international aviation. Under the plan, airlines will have to pay for emissions reduction in other sectors to offset any increase in their own emissions after 2020.



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Critics say the strategy will not have a significant impact – pointing out, for example, that the aviation industry is aiming to only stabilise its emissions, not reduce them.

In contrast, the international shipping sector has pledged to halve its emissions by 2050, based on 2008 levels. Some small shipping companies are even using zero-emissions sail propulsion as a sustainable means of cargo transport.

Sail to the COP is also seeking to promote other sustainable ways of travelling such as train, boat, bus or bike. It says aviation taxes are key to this, because it would encourage growth in other transport modes and make it easier for people to to make a sustainable transport choice.

A growing number of people around the world are already making better choices.
In Thunberg’s native Sweden for example, the term “flygskam” – or flight shame – is used to describe the the feeling of being ashamed to take a flight due to its environmental impact. The movement has reportedly led to a rising number of Swedes catching a train for domestic trips.

Can we sail beyond nostalgia?

Many will dismiss the prospect of a revival in sea travel as romantic but unrealistic. And to some extent they are right. Sailing vessels cannot meet current demand in terms of speed or capacity. But perhaps excessive travel consumption is part of the problem.

The late sociologist John Urry has outlined a number of possible futures in a world of oil scarcity.

One is a shift to a low-carbon, and low-travel, society, in which we would “live smaller, live closer, and drive less”. Urry argues we may be less rich, but not necessarily less happy.

Meantime, the challenges for passenger ocean travel remain many. Not least, it can be slow and uncomfortable – Thunberg likened it to “camping on a rollercoaster”.



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But one Sail to the COP organiser, Jeppe Bijker, thinks it’s an option worth exploring. He developed the Sailscanner tool where users can check if sailing ships are taking their desired route, or request one.

A trip from the Netherlands to Uruguay takes 69 days, at an average speed of 5km/hour.

Some ships might require you to help out with sailing. Other passengers may be required to work look-out shifts. Of course, some passengers may become seasick.

But the site also lists the advantages. You can travel to faraway places without creating a huge carbon footprint. You have time to relax. And out on the open water, you experience the magnitude of the Earth and seas.The Conversation

Christiaan De Beukelaer, Senior Lecturer, University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The air above Antarctica is suddenly getting warmer – here’s what it means for Australia



Antarctic winds have a huge effect on weather in other places.
NASA Goddard Space Flight Center/Flickr, CC BY-SA

Harry Hendon, Australian Bureau of Meteorology; Andrew B. Watkins, Australian Bureau of Meteorology; Eun-Pa Lim, Australian Bureau of Meteorology, and Griffith Young, Australian Bureau of Meteorology

Record warm temperatures above Antarctica over the coming weeks are likely to bring above-average spring temperatures and below-average rainfall across large parts of New South Wales and southern Queensland.

The warming began in the last week of August, when temperatures in the stratosphere high above the South Pole began rapidly heating in a phenomenon called “sudden stratospheric warming”.



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In the coming weeks the warming is forecast to intensify, and its effects will extend downward to Earth’s surface, affecting much of eastern Australia over the coming months.

The Bureau of Meteorology is predicting the strongest Antarctic warming on record, likely to exceed the previous record of September 2002.

(Left) Observation of September 2002 stratospheric warming compared to (right) 2019 forecast for September.
The forecast for 2019 was provided by the Australian Bureau of Meteorology and was initialised on August 30, 2019.

What’s going on?

Every winter, westerly winds – often up to 200km per hour – develop in the stratosphere high above the South Pole and circle the polar region. The winds develop as a result of the difference in temperature over the pole (where there is no sunlight) and the Southern Ocean (where the sun still shines).

As the sun shifts southward during spring, the polar region starts to warm. This warming causes the stratospheric vortex and associated westerly winds to gradually weaken over the period of a few months.

However, in some years this breakdown can happen faster than usual. Waves of air from the lower atmosphere (from large weather systems or flow over mountains) warm the stratosphere above the South Pole, and weaken or “mix” the high-speed westerly winds.

Very rarely, if the waves are strong enough they can rapidly break down the polar vortex, actually reversing the direction of the winds so they become easterly. This is the technical definition of “sudden stratospheric warming.”

Although we have seen plenty of weak or moderate variations in the polar vortex over the past 60 years, the only other true sudden stratospheric warming event in the Southern Hemisphere was in September 2002.

In contrast, their northern counterpart occurs every other year or so during late winter of the Northern Hemisphere because of stronger and more variable tropospheric wave activity.

What can Australia expect?

Impacts from this stratospheric warming are likely to reach Earth’s surface in the next month and possibly extend through to January.

Apart from warming the Antarctic region, the most notable effect will be a shift of the Southern Ocean westerly winds towards the Equator.

For regions directly in the path of the strongest westerlies, which includes western Tasmania, New Zealand’s South Island, and Patagonia in South America, this generally results in more storminess and rainfall, and colder temperatures.

But for subtropical Australia, which largely sits north of the main belt of westerlies, the shift results in reduced rainfall, clearer skies, and warmer temperatures.

Past stratospheric warming events and associated wind changes have had their strongest effects in NSW and southern Queensland, where springtime temperatures increased, rainfall decreased and heatwaves and fire risk rose.

The influence of the stratospheric warming has been captured by the Bureau’s climate outlooks, along with the influence of other major climate drivers such as the current positive Indian Ocean Dipole, leading to a hot and dry outlook for spring.

Anomalous Australian climate conditions during the nine most significant polar vortex weakening years (1979, 1988, 2000, 2002, 2004, 2005, 2012, 2013, 2016) on both maximum and minimum temperatures, and rainfall for October-November, as compared to all other years between 1979-2016.
Bureau of Meteorology

Effects on the ozone hole and Antarctic sea ice

One positive note of sudden stratospheric warming is the reduction – or even absence altogether – of the spring Antarctic ozone hole. This is for two reasons.

First, the rapid rise of temperatures in the upper atmosphere means the super cold polar stratospheric ice clouds, which are vital for the chemical process that destroys ozone, may not even form.

Secondly, the disrupted winds carry more ozone-rich air from the tropics to the polar region, helping repair the ozone hole.

We also expect an enhanced decline in Antarctic sea ice between October and January, particularly in the eastern Ross Sea and western Amundsen Sea, as more warm water moves towards the poles due to the weaker westerly winds.



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Thanks to improvements in modelling and the Bureau’s new supercomputer, these types of events can be forecast better than ever before. Compared to 2002, when we didn’t know much about the event until after it had happened, this time we’ve had almost three weeks’ notice that a very strong warming event was coming. We also know much more about the process that has been set in train, that will affect our weather over the next one to four months.The Conversation

Harry Hendon, Senior Principal Research Scientist, Australian Bureau of Meteorology; Andrew B. Watkins, Manager of Long-range Forecast Services, Australian Bureau of Meteorology; Eun-Pa Lim, Senior research scientist, Australian Bureau of Meteorology, and Griffith Young, Senior IT Officer, Australian Bureau of Meteorology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Why our carbon emission policies don’t work on air travel



File 20180703 116129 1xj9a0q.jpg?ixlib=rb 1.1
The Gillard government’s carbon price had no effect on the aviation industry.
Shutterstock

Francis Markham, Australian National University; Arianne C. Reis, Western Sydney University; James Higham, and Martin Young, Southern Cross University

The federal government’s National Energy Guarantee aims to reduce greenhouse gas emissions in the electricity industry by 26% of 2005 levels. But for Australia to meet its Paris climate change commitments, this 26% reduction will need to be replicated economy-wide.

In sectors such as aviation this is going to be very costly, if not impossible. Our modelling of the carbon price introduced by the Gillard government shows it had no detectable effect on kilometres flown and hence carbon emitted, despite being levied at A$23-$24 per tonne.

If Australia is to meet its Paris climate commitments, the National Energy Guarantee target will need to be raised or radical measures will be required, such as putting a hard cap on emissions in sectors such as aviation.



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Our analysis of domestic aviation found no correlation between the Gillard government’s carbon price and domestic air travel, even when adjusting statistically for other factors that influence the amount Australians fly.

This is despite the carbon price being very effective at reducing emissions in the energy sector.

To reduce aviation emissions, a carbon price must either make flying less carbon intensive, or make people fly less.

In theory, a carbon tax should improve carbon efficiency by increasing the costs of polluting technologies and systems, relative to less polluting alternatives. If this is not possible, a carbon price might reduce emissions by making air travel more expensive, thereby encouraging people to either travel less or use alternative modes of transport.

Why the carbon price failed to reduce domestic aviation

The cost of air travel has fallen dramatically over the last 25 years. As the chart below shows, economy air fares in Australia in 2018 are just 55% of the average cost in 1992 (after adjusting for inflation).

Given this dramatic reduction in fares, many consumers would not have noticed a small increase in prices due to the carbon tax. Qantas, for example, increased domestic fares by between A$1.82 and A$6.86.

The carbon price may have just been too small to reduce consumer demand – even when passed on to consumers in full.

Consumer demand may have actually been increased by the Clean Energy Future policy, which included household compensation.



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The cost of jet fuel, which accounts for between 30 and 40% of total airline expenses, has fluctuated dramatically over the last decade.

As the chart below shows, oil were around USD$80-$100 per barrel during the period of the carbon price, but had fallen to around USD$50 per barrel just a year later.

Airlines manage these large fluctuations by absorbing the cost or passing them on through levies. Fare segmentation and dynamic pricing also make ticket prices difficult to predict and understand.

Compared to the volatility in the cost of fuel, the carbon price was negligible.

https://datawrapper.dwcdn.net/QssWQ/1/

The carbon price was also unlikely to have been fully passed through to consumers as Virgin and Qantas were engaged in heavy competition at the time, also known as the “capacity wars”.

This saw airlines running flights at well below profitable passenger loads in order to gain market share. It also meant the airlines stopped passing on the carbon price to customers.



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A carbon price could incentivise airlines to reduce emissions by improving their management systems or changing plane technology. But such an incentive already existed in 2012-2014, in the form of high fuel prices.

A carbon price would only provide an additional incentive over and above high fuel prices if there is an alternative, non-taxed form of energy to switch to. This is the case for electricity generators, who can switch to solar or wind power.

But more efficient aeroplane materials, engines and biofuels are more myth than reality.

What would meeting Australia’s Paris commitment require?

Given the failure of the carbon price to reduce domestic air travel, there are two possibilities to reduce aviation emissions by 26% on 2005 levels.

The first is to insist on reducing emissions across all industry sectors. In the case of aviation, the modest A$23-$24 per tonne carbon price did not work.

Hard caps on emissions will be needed. Given the difficulty of technological change, this will require that people fly less.

The second option is to put off reducing aviation emissions and take advantage of more viable sources of emissions reduction elsewhere.

By increasing the National Energy Guarantee target to well above 26%, the emission reductions in the energy sector could offset a lack of progress in aviation. This is the most economically efficient way to reduce economy-wide emissions, but does little to reduce carbon pollution from aviation specifically.

The ConversationAirline emissions are likely to remain a difficult problem, but one that needs to be tackled if we’re to stay within habitable climate limits.

Francis Markham, Research Fellow, College of Arts and Social Sciences, Australian National University; Arianne C. Reis, Senior lecturer, Western Sydney University; James Higham, Professor of Tourism, and Martin Young, Associate Professor, School of Business and Tourism, Southern Cross University

This article was originally published on The Conversation. Read the original article.