CO2 buried underground turns to rock in just two years
Here’s a delightful turn-up for the books. I hate writing about climate change, but that’s chiefly because it’s never good news, is it? Whether it’s the Earth’s temperature heating up yet again or a future President Trump administration jettisoning our extremely precarious climate change agreement, there’s never a good news story to give us hope that maybe we’re not quite as doomed as we thought.
Well, here’s something positive for a change: a climate change related news story which is objectively good news, and could change the way we think about tackling our impending disaster, with a couple of caveats I’ll mention later. An international team of researchers has discovered that they can pump CO2 underground and have it convert to rock in just two years. To put that into perspective, they were expecting the process to take eight to 12 years.
“Our results show that between 95 and 98 percent of the injected CO2 was mineralised over the period of less than two years, which is amazingly fast,” explained lead researcher Juerg Matter from the University of Southampton.
Here’s how they did it. Based at the world’s largest geothermal power plant (Hellisheidi in Iceland), the researchers mixed carbon dioxide with water, and injected it into the basalt below the plant. When the volcanic basalt 400-800 metres underground is exposed to carbon dioxide and water, the carbon solidifies into carbonate minerals – neatly preventing it from entering the atmosphere.
“Carbonate minerals do not leak out of the ground, thus our newly developed method results in permanent and environmentally friendly storage of CO2 emissions,” said Matter, explaining that basalt is one of the most common rock types on the planet, making this a genuinely plausible form of carbon capture.
But look, it wouldn’t be a climate change story if there wasn’t a “but”, so here’s the come down. Firstly, although basalt is abundant as far as rocks go on Earth, little of it is directly below land, let alone a power plant, as in Iceland. That’s not necessarily an insurmountable problem, because although although the idea of the world exporting all its CO2 to Iceland is very unlikely, there is the potential to pipe CO2 directly to the ocean floor, much of which is basalt. So not insurmountable, but an infrastructure headache.
The second is one of scale. This was a relatively small trial – something Matter himself acknowledges, as he explains the next step is to upscale the operation. But just how much upscaling this would require to make a real difference is mindboggling. At the moment, the process captures around 5,000 tonnes of CO2 per year, which sounds great, until you do some sums and realise that the European Union alone spat out 3,420,000,000 tonnes in 2014.
With those numbers dancing around your head, you quickly realise that this isn’t going to be a simple elixir to fixing the serious problem of climate change. As Stuart Haszeldine, professor of carbon capture and storage at the University of Edinburgh told The Guardian, “This needs to be used as well as the existing propositions, because the problem to be solved of thousands of million tonnes of CO2 emissions per year in the world is immense and no single remedy is anywhere near big enough or fast enough.”
So this is a genuinely exciting discovery, but we need more solutions, and fast. It’s still extremely hard to escape the likely truth that the only truly effective remedy is to dramatically reduce our emissions – significantly further than what we’ve already signed up to. Convincing people to change their lifestyles for this to happen is arguably an even bigger challenge than the scientific hurdles of trying to avoid that difficult conversation in the first place.