About 40km from Warrnambool in south-western Victoria is Australia's first demonstration site for storing carbon dioxide pollution deep underground. It doesn't look like much — a few water tanks, sheds and pipes in a paddock — yet plans to meet the internationally agreed climate change target are betting on the success of projects like this.
The company behind it, the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC), calls it 'the world's largest carbon capture and storage demonstration project', a $100 million project of 'global significance'.
CO2CRC was established more than a decade ago with federal funds, and the current chairman is former federal Minister for Resources and Energy Martin Ferguson. It researches carbon capture and storage (CCS) techniques to capture the pollution from power stations and sequester it deep beneath the earth so it won't overheat the planet.
For decades, environment groups maligned CCS as little more than an excuse for the fossil fuel industry to keep burning coal and gas. It was marketed as 'clean coal', but has never fulfilled its promise at commercial scale. Despite this, in recent years, CCS has become an unspoken assumption of the international agreement to limit warming to well below 2 degrees.
'Rather than requiring that nations reduce emissions in the short-to-medium term, the Paris agreement instead rests on the assumption that the world will successfully suck the carbon pollution it produces back from the atmosphere in the longer term,' climate scientist Kevin Anderson, from the Tyndall Centre in the UK, wrote in Nature soon after the 2015 Paris climate change conference. 'A few years ago, these exotic Dr Strangelove options were discussed only as last-ditch contingencies. Now they are Plan A.'
Specifically, much of the scenario modelling relies on something called bioenergy with carbon capture and sequestration (BECCS). It involves growing crops such as corn or switchgrass, which take up carbon dioxide from the atmosphere through the natural process of photosynthesis. They would then be burned in power stations to generate electricity, with the resulting emissions captured and stored underground.
This isn't a fringe strategy anymore. As Anderson writes, it is now a big part of the mainstream, politically preferred approach to address global warming.
In an article for Nature Geoscience, he reviewed the Intergovernmental Panel on Climate Change (IPCC) database of scenarios to meet the 2 degree target and concluded. 'In plain language, the complete set of 400 IPCC scenarios for a 50 per cent or better chance of 2°C assume either an ability to travel back in time or the successful and large-scale uptake of speculative negative emission technologies.'
"The US National Academy of Sciences calls for a 'rapid expansion and scale up' of demonstration projects. Environment groups would be wise to accept that advice."
It's the same story with scenarios to meet the more ambitious 1.5 degree target. 'All of the one and a half degree warming scenarios have assumed some form of carbon capture and storage or bioenergy with carbon capture and storage,' explains climate scientist David Karoly from the University of Melbourne.
Even key figures intimately involved with the UN climate change negotiations are critical of these assumptions. In a 2016 conference at Oxford University, Janos Pasztor, Senior Advisor to the UN Secretary-General on Climate Change, expressed his doubts: 'Sometimes I wonder if BECCS is just a fudge factor to make our models reach 1.5°C or 2°C, or whether it's a real prospect.'
Pasztor is now heading an initiative that's investigating the international governance of geoengineering — a catch-all term for technological solutions to global warming. It's yet another indication that, at least among the political and scientific elite, the debate is shifting beyond merely cutting emissions to a 'portfolio' of strategies, including geoengineering.
Why are we even contemplating such speculative solutions to global warming? There are a few theories. Anderson argues it's because what is really needed — deep and early cuts to emissions — is politically unpalatable and 'cannot be reconciled with the mantra of economic growth'. Other climate scientists have called it a 'pay later approach': we assume we'll be able to suck carbon dioxide out of the atmosphere later so we can justify emitting more now.
Then there's the argument that 2 degrees or even 1.5 degrees of warming might not be a safe level, considering we're already seeing devastating coral bleaching, more extreme heatwaves and thawing of the Arctic permafrost. If you take that view, then along with urgently cutting emissions, we'll also need to reduce the total stock of carbon dioxide already in the atmosphere. It's possible to do this by enhancing natural processes — such as replanting forests — but the uptake would be slow, and the storage capacity is limited.
BECCS is favoured because it could store much more carbon, much more quickly. But there's a long list of caveats. A 2015 report by the US National Academy of Sciences explains that bioenergy crops would directly compete with food crops for arable land. Forests might have to be cut down to plant them. While the fossil fuel industry has decades of experience storing carbon dioxide underground (ironically, they use it to force out more oil and gas from depleted reserves), it's at small scales compared with what would be required to make a difference to global temperatures. There are also concerns around leakage and increased risk of earthquakes if injecting carbon dioxide puts too much pressure in the underground reservoir.
For all of these reasons, any form of CCS should be viewed with great skepticism. It is not, and never can be, a substitute for dramatic cuts in greenhouse gas emissions.
But nor can it be dismissed out of hand. Carbon dioxide persists in the atmosphere for centuries or millennia; it's almost certain we'll need to draw down some of it over that timescale, and while CCS is still a nascent technology, it's more advanced than some other techniques to do the same job. The US National Academy of Sciences calls for a 'rapid expansion and scale up' of demonstration projects. Environment groups would be wise to accept that advice.
It seems crazy that we're gambling our future on pollution-sucking gadgets we haven't built yet and that might not work at scale. But that's the reality of where decades of political dithering and delay on climate change have brought us: to a paddock in south-western Victoria, pinning our hopes on a couple of pipes in the ground.
Greg Foyster is a Melbourne writer and the author of the book Changing Gears.