Earth’s climate has been edging towards a scene usually reserved for a post-apocalyptic movie. Some posit geoengineering as a radical fix to climate change. Others say the risks are too high and its proponents mad. Welcome to the debate where science fiction meets climate science.

If you visit a block of land near the West Australian dairy town of Harvey in a few years’ time, you will see a few pipes sticking out of the ground, a solar panel and an aerial for communications devices. There may be a hut and some room for parking.

These will be the only visible signs of the South West Hub project, designed to test the feasibility of pumping megatonnes of carbon dioxide into the vast Wonnerup sandstone layer, a kilometre-and-a-half deep beneath the Jarrah-Marri trees on the surface.

The gas will be liquefied in a nearby compressor building – an anonymous farm shed – and transported to the injection site via underground pipes.

Wonnerup is an example of carbon capture and storage, one of a suite of technologies known as geoengineering, or climate engineering.

Geoengineering is a mixed bag, but the idea involves large-scale interventions at the level of the whole planet, with the goal of fixing the climate. It’s tricky, dangerous, and largely considered “fringe science”.

The proposals come in two main flavours. One is carbon dioxide removal, which strips the gas from the atmosphere and slowly restores atmospheric balance. A mix of techniques would be needed: hundreds of factories like Wonnerup, billions of new trees and plants, plus contentious technologies such as artificially encouraging the growth of plankton.

The second is solar radiation management, intended to cool the Earth by stopping the sun's heat from reaching the planet’s surface. That can be achieved by pumping minute particles into the atmosphere, but carries the risk of killing billions of people.

Right now, we don’t have the tools or the knowledge to deploy these fixes. But some prominent climate scientists argue that as carbon emissions continue to rise, geoengineering will have to be employed to avoid catastrophic climate change.

Last December's meeting of world leaders in Paris produced a voluntary agreement to try to limit the global temperature increase to 1.5C over pre-industrial levels, and to not exceed 2C – the widely agreed level of devastating heat increase. But agreement and actual efforts didn’t seem to go hand in hand.

“The roar of devastating global storms has now drowned the false cheer from Paris,” a team of 11 climate scientists wrote in a January letter to The Independent, “and brutally brought into focus the extent of our failure to address climate change. The unfortunate truth is that things are going to get much worse.”

University of Cambridge Professor Peter Wadhams says: “Other things being equal, I’m not a great fan of geoengineering, but I think it absolutely necessary given the situation we’re in. It’s a sticking plaster solution. But you need it, because looking at the world, nobody’s instantly changing their pattern of life.”

Since then, temperatures have been soaring month after month, we’ve learned that the Great Barrier Reef is in extremely poor health and bleaching rapidly, while new quests continue to unearth more fossil fuels.

As we’re failing to keep the planet pleasant and habitable for future generations, could we instead fix the climate with technology? With geoengineering?

Debate about geoengineering in Australia is “almost being avoided”, according to Professor David Karoly, a noted atmospheric scientist at the University of Melbourne. He is a member of the Climate Change Authority, which advises the federal government, and was involved in preparing the 2007 IPCC report on global warming.

“There's very little discussion on it in terms of government circles, there's very little research on it, there's very little discussion of it in what might be called mainstream science,” Professor Karoly says.

Policymakers are including geoengineering in their plans, but many technologies are still unproven and potentially dangerous.

“You'll generally find among climate scientists that almost all are opposed to geoengineering,” says Professor Jim Falk, of the University of Melbourne's Sustainable Society Institute. “They're already pretty concerned about what we've done to the climate and don't want to start stuffing around doing other things we only half-understand on a grand scale.”

When the US National Academy of Science launched a report last year analysing geoengineering options, committee head Marcia McNutt, a geophysicist, was asked if any should be deployed. She replied “Gosh, I hope not”.

The report considered carbon dioxide removal and solar radiation management so risky it used the term “climate intervention” instead of geoengineering, arguing the term “engineering” implied a level of control that doesn't exist.

But the IPCC has considered scenarios where such engineering would be necessary: its 2014 assessment report mentions bio-energy carbon capture and storage (known as BECCS), where plant fuel is burned and the resulting carbon dioxide buried.

And the Paris Agreement noted there would be need for a “balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases” in 2050-2100.

“A few years ago, these exotic Dr Strangelove options were discussed only as last-ditch contingencies,” wrote Kevin Anderson, deputy director of the UK's Tyndall Centre for Climate Change, of the Paris talks in Nature magazine.

“Now they are Plan A.”

The term “geoengineering” raises the spectre of a James Bond villain cackling in his lair and planning to make volcanoes erupt at the push of a button. And that’s quite fitting, given that one approach to solar radiation management consists of mimicking the fallout from such giant explosions.

Treating the problem like an outlandish movie script may be the only way of comprehending the scale of the challenge. To reduce atmospheric CO2 levels by 1ppm – approaching the volume needed to stabilise global temperature – requires the withdrawal of 18 gigatonnes of gas, the equivalent of 18,000 South West Hub plants running for a year.

Tim Flannery, the former Australian of the Year who helped raise the profile of climate change, is vocal in supporting some geoengineering approaches. He prefers the less-toxic term “Third Way technologies”, based on the Earth's natural processes.

Flannery says those which work at the gigatonne scale – the only ones which will dent the problem – may take decades to be developed.

“The only way you can get to a Paris-like outcome is by slamming hard on emissions,” he says, “reducing them as fast as humanly possible as well as investing now in these technologies that'll give you these gigatonne gains in 20 or 30 years time.”

”The question for most of these technologies is – we don't know if they work. But we need them to work.”

Flannery says solar-radiation management approaches should be treated with great caution, as they mask the problem: they will reduce the temperature, but not affect rising CO2 levels, leaving the oceans ever more acidic. That could see a catastrophic loss of reefs and oceanic life, devastating the aquatic food chain.

Ironically, one of the reasons the atmosphere isn't already at a 2C warming mark, says Professor Karoly, is due to the aerosols already in the atmosphere – an unintentional form of solar radiation management.

He says the current best estimate of stabilising the temperature at that level, with a 50 per cent likelihood, is for a carbon equivalent reading of 420-480ppm. The current figure is 481ppm, and rising at 3ppm per year.

Solar radiation management – deliberate and large scale – might buy time in an emergency, says Flannery. “There's a broad highway to hell that's easy to go down and it's really cheap, relatively. It's instantly effective, nations can do it unilaterally and it gives you a lower temperature.

“But there's a narrow, crooked, winding path to heaven which is the carbon reduction stuff. It's at a very early stage, but that actually does solve the problem.”

Once we capture carbon, it can actually be used productively. American researchers have produced carbon nanofibres from atmospheric carbon dioxide – initially only 10g per hour, but they are convinced it could scale.

There could be vast baths of molten chemicals across large swathes of the Sahara Desert, powered by solar radiation, forming layers of a valuable building material on submerged electrodes.

A research project at a California university has gone further, manufacturing a building material dubbed CO2NCRETE from captured carbon dioxide. A pilot plant at Australia’s University of Newcastle is investigating whether a similar process, combining excess CO2 from an Orica plant with minerals to form building materials, has commercial potential.

Flannery is interested in desktop studies on carbon-sucking seaweed and algae, as well as research reporting that carbon dioxide can be made to fall as snow over the Antarctic.
Picture this: the temperature plummeting well below freezing until a blizzard of dry ice cascades onto the barren plains below, each cuboctahedral flake representing a miniscule improvement in carbon levels, to be stored safely – somehow – from warming into a gas and re-entering the air.

“We're at very, very early days,” Flannery warns. “Various approaches have different favourable aspects to them, but I don't think any of them are anything like a silver bullet.”

Flannery's championing of unorthodox technologies – even as avenues for research – isn't shared by many high-profile climate change campaigners. David Karoly calls Flannery's interest “surprising”. He deems ideas such as dry ice snowfall in Antarctica as “rather technofix solutions”.

“How do you get sufficient CO2 out of the atmosphere and store it?” asks Professor Karoly. “It's probably the most inhospitable environment in the world and he's talking about – if you work out what this equates to, it's a mountain higher than Everest, the size of a soccer field every year.”

The Paris target of a 1.5C rise is “virtually impossible” without new technologies, he says, which “have not been proved either commercially viable or without major harm”.

“My concern is, the cure might be substantially worse than the disease.”

Clive Hamilton, professor of public ethics at Charles Sturt University, who wrote about geoengineering in his 2013 book Earthmasters, is more blunt.

“The schemes [Flannery] proposes are real pie-in-the-sky stuff, way out there,” he says. “He seems to have been sucked in by a kind of strange techno-promise that'll get us out of this.”

Australian geoengineering research lags far behind the world leaders in the US, UK and Germany. It’s limited to a handful of scientists in Sydney and Hobart, and our major achievement is helping to halt commercial oceanic geoengineering.

The federal government, via its Direct Action policy, focuses on carbon sequestration without the crazy technofix label. Instead it backs land-use practices such as planting new forests, and prioritises soil enhancement, mangrove protection and rainforest recovery.

“There was an enormous groundswell of support for these activities in Paris,” a spokesperson for the Department of the Environment says. “Other actions [in the geoengineering field] would have an enormously high safety bar to cross and are a long way from proof.”

Meanwhile, CSIRO looks set to embark on an expansion of its geoengineering research program, both at land and sea. In a recent memo to staff announcing 350 job cuts at the organisation, CSIRO head Larry Marshall nominated “climate interventions (geo-engineering)” as one area in which it would seek a “step change” in knowledge.

“CSIRO is currently working through the detail of our future climate adaptation and mitigation research, and will include research relevant aspects of onshore and offshore geo-engineering. The scale and scope of this research is still to be determined,” a CSIRO spokesperson told SBS.

Jim Falk categorises geoengineering proposals along various lines, including how big a project needs to be for credible deployment, how big an impact it would have, whether it is reversible, what governance is required, how much it would cost, and the risks involved.

“Then you can say different proposals have different footprints,” Falk says, “and depending on the footprint you can suggest what sort of barriers you would want for their regulations before you would allow an experiment to take place.”

Unlike attempts to reduce global carbon emissions – where everyone must do their part for action to be effective – what scares scientists about solar radiation management is the relative ease of one person launching a planet-wide experiment.

Spraying sulphate particles into the atmosphere from aircraft or balloons is known to reduce temperatures. It mimics what happens when volcanic ash blankets the atmosphere.

There would be spectacular sunsets as solar rays interact with the particles, with brilliant red eddies splashing the evening sky, similar to those in Edvard Munch's famous painting The Scream.

And it has been costed at just $US10 billion a year.

One test in August 2008 was conducted on land 500km southeast of Moscow by Yuri Izrael, Russian President Vladimir Putin's science advisor. He and his team rigged aerosol sprays on a helicopter and car chassis, measuring how solar radiation was retarded at heights up to 200 metres.

“China might decide to pump a load of sulphur into the atmosphere and not tell anyone about it,” says Rosemary Rayfuse, a Law professor at UNSW and a global authority on regulating geoengineering. “Or Australia could do it. Anybody could. That's the other problem – it's so easy to do.”

Billionaires Bill Gates and Richard Branson could step forward, says Anita Talberg, a PhD student in the governance of climate engineering at the University of Melbourne. Both support geoengineering and have funded research.

“They could just decide suddenly, 'I could do enough benefit for the poor and vulnerable in the world, I could just do it and save them from the climate crisis.'”

Such a move could be catastrophic, most immediately due to the risk of drought in the tropics, devastating the food security of billions of people. Those colourful sunsets are projected to see lower rainfall.

The sky will bleach white during the day, while ozone depletes in the tropics - where most of the world's population live. As the temperature falls, levels of UV radiation will rise, leading to an upsurge in skin cancers.

Professor Andy Pitman, of the Climate Change Research Centre in Sydney, is a member of the World Climate Research Program.

The only role he sees for sulphate injection is alongside steep cuts in carbon emissions. “If people are talking about it as a substitute for that, the technical term you'd use is 'cloud cuckoo land'.”

But he hopes it's never necessary.

“God, I hope not. We have a well-studied problem called global warming – we're not sure of every detail – that would breach every ethics experiment on the planet if you proposed it as an experiment.

“All those problems relate to solar radiation management and I'd suggest any country that tried it at any significant level would find itself in every court in the world.”

There are smaller-scale approaches, he says, without the “ethical problems”. One is painting roofs white to reflect sun, a backyard approach anyone can try, and which would help cool interiors during hot summer days.

Another is genetically modified crops with a higher reflectivity, with variations as simple as leaves that are hairier or have a waxier coating.

Harvard University's Professor David Keith is leading more research into solar radiation management, arguing in a 2015 paper that the technique could be used in a “temporary, moderate and responsive scenario”.

“Even if we make deep emissions cuts, it might be that the benefits of solar geoengineering outweigh the risks,” he tells SBS. “Or maybe not. To know, we have to decide to learn more.”

The belief in a technical solution – that because we have to find something, we will – has psychological roots in an effect known as 'optimism bias', says Melbourne psychologist Dr Susie Burke, who has expertise on issues relating to the environment, climate change and natural disasters.

“It's intrinsic to humans to be optimistically biased,” she says, “and it's great because it gets us out of bed in the morning and gives us a healthy motivation. But with respect to climate change, it means we end up minimising our personal risk and even risks that pertain to us – and believing the worst problems will happen to other people, somewhere else or into the future.”

She adds, “With the general population who are struggling to make significant changes to their lifestyle, deep down there is a belief that someone, somewhere will come up with something to solve the problem.”

Even talking about geoengineering carries the risk of “moral hazard”, that a solution to rocketing carbon emissions means they can continue unabated. That scenario troubles many.

“There's a moral hazard in not discussing these things as well,” says Tim Flannery, “because we know we're going to need them.”

The worst-case scenario – international agreements fail to stop emissions from rising – would force the use of extreme measures. Clive Hamilton thinks sulphate injection is the most likely use of geoengineering, though not yet.

“If we have a series of years where there are catastrophic droughts, heatwaves and hurricanes which cause massive impacts in several countries – also tipping points, so permafrost is now irreversibly melting – what kind of political and geostrategic environment are we going to be facing?” he asks.

“I think in that kind of scenario – which is not just possible but fairly likely – certain scientists promising they can rapidly reduce the earth's temperature within a year or two are going to start looking increasingly attractive to some nations.”

Andy Pitman says that could lead to war: “You can imagine a situation – and it's not too far-fetched – where country X starts a major campaign around sulphur injections into the atmosphere, country Y's rainfall dramatically declines and is going into serious long-term famine, and that instigated a military response.”

And if carbon emissions continued to rise, the sulphate injection would have to be continuous. Otherwise, the particles would drop out of the atmosphere, leading to a sudden, highly disruptive jump in temperature.

If a war, say, or a pandemic was responsible for the break in sulphate injection, the compounding effects could be existential. Talking of human extinction in such a scenario is not too far-fetched.

The possibilities are less apocalyptic for some form of carbon capture and storage. Clive Hamilton identifies land being used by the likes of BECCS – bio-energy carbon capture and storage – to capture carbon as one of the main changes in geoengineering in the last few years.

Plants and trees would be grown for fuel, and the resulting carbon emissions from power generation would be stored away. There’s an example of this in Illinois at an ethanol production plant.

But there are questions over BECCS, not least that “no such economic process [is] available at this point and there may never be”, says Jim Falk.

The sheer amount of land needed is staggering, too. In a February 2016 paper in Nature,environmental scientist Philip Williamson estimated that one-third of the world's arable land (430-580 million hectares of crops) would need planting for BECCS use to limit the temperature rise to 2C by 2100. This would accelerate deforestation and, given “not unrealistic” assumptions, see carbon emissions actually increase.

Oliver Munnion, of the UK-based BioFuelwatch website, argues that BECCS is more dangerous than solar radiation management. “It's the most outrageous,” he says. “It's also the favoured approach amongst policy-makers, scientists and industry.

“The idea that we'd harm proven carbon sinks – forests and soils – to create an unproven and untested carbon sink underground is the antithesis of what climate policy should be geared towards.”

The problem facing geoengineering advocates is that most dangerous schemes are possible, but need to be used as a last resort, while the most promising schemes aren't possible at scale. Even if they were, the numbers quickly turn ugly.

In the Nature article, Philip Williamson estimated that growing seaweed as a carbon pool would use nine per cent of the world's oceans, with unknown environmental impacts.

Utilising the simple solar-radiation management tool of laying a reflective rock on the ground to reduce carbon levels by 12 per cent would need 1-5 kg/sqm of rock to be applied to 15-45 per cent of the earth's surface, at a total cost of US$60-600 trillion.

That means an area of land at least the size of the old Soviet Union would have to be set aside and the global economy bankrupted.

The further you look, the more improbable geoengineering concepts become. A presentation to the 2016 American Meteorological Conference on Atmospheric Science called for lasers in the sky to microwave and neutralise methane clouds (another greenhouse gas).

UNSW Law professor Rosemary Rayfuse recalls one UK project looking at increasing the reflectivity of the oceans by making white foam, which had to persist for at least three months: “They were proposing to cover the oceans in meringue, which I thought was rather funny!”

David Karoly calls the idea of hanging mirrors in space to reflect sunlight “just stupid”, calculating the need for one million square kilometres of alfoil. Flannery agrees: “Anything that masks the problem, and lets people think they've solved it, is a danger.”

Cutting carbon emissions drastically, and now, would start to solve the problem. But that isn't happening. Campaigners such as Tim Flannery are crossing their fingers that carbon-scrubbing technology we need to take us on “the narrow winding path to heaven” is developed in time.

If neither happens, we'll be heading down the “broad highway to hell” of having to rely on solar radiation management, where the devil we don't know is better than a climate gone rogue.

The effects of pumping simulated volcanic fallout into the atmosphere could dwarf the biggest eruptions in history. Start preparing for vivid red sunsets – and an uncertain future.

One geoengineering approach, ocean fertilisation, could see carbon parks in the ocean, dedicated areas where ships would moor for a season, seed the water to stimulate plankton growth, and move on.

Each site, according to research by Sydney's Ocean Nourishment Corporation, could sequester 5-8MT of carbon per year and also increase fish stocks.

Iron was used in the biggest geoengineering experiment to date in 2012, when 110 tons of orange ferrous powder were dumped off the islands of Haida Gwaii, on Canada's west coast.

A 35,000sqkm bloom of algae formed, boosting salmon numbers for local First Nations fishermen, who had paid US$2.5m to fund the project. A NASA satellite image shows dense algal concentrations in yellows and browns along the coast and spreading out to sea.

But Andy Pitman singles out iron fertilisation as the most “bizarrely stupid” scheme he's come across. “We don't know what the consequences would be,” he says. “We do know we'd have to keep putting iron into the ocean indefinitely and the problem with all these schemes is they don't stop ocean acidification.”

Ocean Nourishment Corporation wants to use nitrogen instead of iron and has modelled a deep-water location 150km off Dampier, WA, for testing – but for now these tests can't proceed, as two international agreements restrain the use of geoengineering at sea.