On a remote plateau in southwest Iceland, surrounded by dark crags and swaths of green moss, a major new facility has opened with the bold promise of helping to reverse climate change by removing carbon dioxide from the air.
It is the world’s biggest such complex and, according to its operators, will capture 4,000 tonnes of the greenhouse gas per year in boxes the size of shipping containers. This will then be funnelled deep underground to transform – astonishingly – into harmless rock.
As world leaders meet in Glasgow for COP26, the United Nations’ climate summit, scientists are touting this cutting-edge yet costly technology as a key solution to the climate crisis.
Others warn its high price and voracious appetite for energy are obstacles to neutralising emissions on a global scale. Its fiercest critics brand it a naive and unproven tactic that offers the worst polluters a smokescreen.
But with plans under way for even larger “direct air capture” operations than the one in Iceland, proponents say this pioneering technology can help humanity to make the world carbon neutral and limit heating to the internationally agreed target of 1.5 degrees Celsius (2.7 degrees Fahrenheit).
“Direct air capture is absolutely essential for achieving net zero,” said Professor Stuart Haszeldine, an expert in CO2 storage and climate engineering at the University of Edinburgh.
“We have to have technological solutions to get ourselves out of this problem that technology has created. I’m all in favour of planting trees and rewilding, but none of those in themselves is enough. Direct air capture, together with using much less fossil fuel, is part of the remedy.”
A half hour’s drive outside of Iceland’s capital, Reykjavik, the carbon-capture plant in Iceland opened in September and uses human-sized fans to draw air into its ducts. There, CO2 builds up on a dense filter before being freed by 100C (212F) blasts of heat from renewable geothermal energy, supplied by the island’s volcanic underbelly.
The gas is then dissolved in water and pumped through pores and cracks of basalt rock as deep as 2,000 metres (6,600 feet) below ground. There, it cools, reacts with minerals and, within two years, changes from a climate-heating gas into risk-free rock.
Named “Orca” — almost identical to the Icelandic word for energy — the industrial facility was set up by Climeworks, a Swiss carbon capture company, and Carbfix, an Icelandic group that specialises in turning CO2 into stone.
Personnel at the plant insist that emissions reduction must go hand in hand with emissions removal.
“[This technology] does not give us an excuse for continuing with business as usual,” said Sandra Ó Snæbjörnsdóttir, a geologist who oversees CO2 storage there. “Firstly, we have to not emit CO2. We have to decarbonise.”
Rising concentrations of atmospheric CO2 are forcing up global temperatures and with them an increase in droughts, floods, and other extreme weather events, all while causing severe damage to ecosystems that underpin life on Earth.
Conversely, experts say it is not enough simply to reduce emissions of greenhouse gases. Substantial and sustained capture is crucial too — particularly as a recent UN paper found that governments plan to extract more than double the amount of fossil fuels needed to keep global temperatures to safe levels.
“There is no historical precedent for the scale of the necessary transitions,” said a landmark 2018 report by the Intergovernmental Panel on Climate Change. “Conceptually, it is possible that techniques to draw CO2 out of the atmosphere could contribute to limiting warming to 1.5°C.”
A mass rollout
The complex in Iceland showcases just one of several methods to remove CO2 from the air. All are at different stages of readiness. Some require initial lab research, others are on the brink of large-scale deployment.
One technique is more familiar: planting trees, the original “carbon capture hubs”. They absorb atmospheric CO2 while boosting wildlife habitats — critical to stemming biodiversity loss and protecting against flooding.
But trees take time to grow and, when trying to lock away carbon indefinitely, they remain vulnerable to logging, land clearance or wildfires fuelled by a deteriorating climate. Scientists worry too about the huge land and water requirements for this tree-planting tactic.
Experts say nature-based solutions are important but not enough in themselves. Yet the current scale of carbon dioxide emissions dwarfs our man-made tools to remove them. Even as human activities release tens of billions of tonnes of CO2 into the atmosphere yearly, the new plant in Iceland is able to capture just 4,000 tonnes — a tiny fraction of this planet-heating gas.
Experts argue for a mass rollout of these facilities with far greater CO2-capturing capacity.
“You’re going to need something like 10,000 of these around the world,” said Haszeldine. “That sounds like a big number but that’s just the same as the number of big power plants around the world. So it’s the sort of thing that has been done already.”
These are already on the horizon. Canadian company Carbon Engineering has earmarked Scotland and the US state of Texas for two huge complexes and says each one will be able to remove up to a million tonnes of CO2 every year — the equivalent of 40 million trees apiece.
“These facilities will demonstrate that large-scale [direct air capture] technology is a feasible, affordable and available tool that is ready to help bring global emissions down to net zero, and eventually net negative,” said Steve Oldham, head of Carbon Engineering.
‘Stop fossil fuel projects’
Oldham’s optimism is not shared by all.
Gyorgy Dallos, a climate campaigner at Greenpeace International, argues that presenting carbon capture technology as a solution “is at best naive and at worst dangerously cynical” — describing it as “expensive, undeveloped and unproven to work at scale”.
“It serves as a smokescreen to distract from a continuing rise in emissions,” he said. “The real solution is immediate emissions reduction which means, among other things, an immediate stop to new fossil fuel projects.”
Carbon capture technology certainly faces challenges — not least the price. Costing upwards of $600 per tonne, the bill for removing billions of tonnes of carbon dioxide would be eye-watering.
However, prices are likely to get cheaper as the technology improves and expands — just as once-costly solar panels have plummeted in price. Experts predict that the cost will drop to below $200 per tonne within 20 years. Meanwhile, costs can be offset by selling the harvested CO2 to agricultural, beverage or energy companies, whether to grow food, add fizz to drinks, or combine with hydrogen to make fuel.
Another issue is that CO2 makes up only about 0.04 percent of the air so requires large amounts of energy to extract it from vast volumes of air. Green and reliable power sources are key.
Iceland’s high concentration of volcanoes made the island nation an obvious choice thanks to its cheap and bountiful supply of geothermal energy, in addition to the right kind of rocks for CO2’s mineral storage. Those conditions open the door to further air capture hubs in areas as diverse as Hawaii, the East African Rift, parts of Russia and Southeast Asian nations.
But the process needs substantial quantities of water as well as the presence of porous basalt rock — widely available on continental margins but scarce elsewhere.
The clock is ticking and some environmental groups remain deeply sceptical of the technology. In a report this year, Friends of the Earth dismissed Direct Air Capture as “futuristic, unproven and dangerous”, adding the technique is “unlikely to ever work at scale” and warning investment in it “could even lead to greater fossil fuel extraction”.
But from the lava field in Iceland, as air is sieved of CO2 in an audacious bid to cool the planet, the path out of the climate crisis appears different.
“We don’t have any silver bullets,” said Snæbjörnsdóttir. “But we do have a portfolio of solutions that, combined, can probably help us with the task ahead.”