By Chris Davey
The 2019 BBC documentary Climate Change: The Facts was strong on action needed to curb emissions, but also included a section on drawing down carbon dioxide, CO2, from the atmosphere. Chris Stark, then Chief Executive of the Climate Change Committee, pointed out that we already have the means of drawing down carbon from the air: trees.
Reforestation and afforestation: more trees equals good, fewer trees equals bad. Forests are biodiverse, which of course is good for wild creatures, and indirectly for us. Then there is the aesthetic aspect of forests, and indeed “forest bathing”, with compounds coming off the leaves and doing us good as we breathe in. But it is estimated that the sum total of forest needed to absorb our current emissions would cover half the planet. Of course, it’s not only trees that sequester carbon – the soil does too, and the sea; and especially wetlands if properly managed. But this does highlight the enormity of what we have to do.
Back to the documentary, that section went on to show direct air capture (DAC) of CO2 by the Orca project in Iceland, which draws in air, separates the carbon dioxide, compresses/dissolves it in water, and sends it down to the basalt rock below where it forms stable carbonates. These then appear as white specks in the natural cavities in the rock – a sample of which is shown in the documentary. Narrator David Attenborough points out that this was a small project that would need to be replicated at scale to have any significant effect on the CO2 currently in the atmosphere.
Recently, in May 2025, there was a three-part series on BBC1, in the mode of “Simon Reeve visits an interesting place” (he’s “done”Cornwall) and this was Reeve covering Scandinavia in three hours, which he acknowledged merely scratched the surface, as it included Iceland, bringing the total number of countries visited to five. (Many interesting features of modern Scandinavia were revealed, including the rise of gang crime in Stockholm – yes Stockholm! But all that is out of scope here.)
In Iceland, he visited a DAC installation called Mammoth, which draws air in, separates the CO2 and sends it down the basalt rock below. A sample of the rock with white flecks of carbonate was shown. This is a development of the previous Orca project, and is, as the name suggests, much larger – about ten times larger – but the principle is the same, and Reeve also pointed out that this was a limited-scale project that would need to be replicated at scale to have any significant effect on the CO2 currently in the atmosphere.
It has been estimated that the Orca project would draw down about three seconds worth of annual carbon dioxide at the rate we’ve been putting it into the atmosphere. So if that is so, I guess it follows that the new “mammoth” version will do about half a minute’s worth of emissions. The tech is enticing, and it is mentioned that the air coming out of Mammoth is probably the cleanest on the planet – Reeve fills his lungs. Whether the plant takes out other pollutants is unclear. Given that the CO2 is stored in stable solid form, that seems a sustainable process which should ensure that it won’t leak back into the air. The main problem is the scale, or lack of it. But there are other issues to address.
Firstly, this is of course a high-tech solution, and we just love tech. Once we crack this at scale, it means we can emit as much as we want, because we can suck it all back. Maybe. Worth mentioning here that these projects in Iceland use the country’s geothermal energy to run them, and it is only using that renewable energy that makes such tech at all viable. Not much point in using fossil fuels and emitting carbon in order to draw some down.
The second point is the kicking-the-can-down-the-road issue. DAC works, but at its current scale it’s been compared to “bailing out the Titanic with a teaspoon”, so we are relying on future generations (are you listening, future generations?) to sort it out properly and fix our greenhouse effect problem. Our current policies on “net zero” depend on this.
The can-kicking is the thing that bothers me most. Roman Krznaric expresses it something like this: we have stopped colonising countries, mostly in the Global South, in order to build our comfortable lifestyles here in the Global North; now we are in effect colonising the future. If we don’t act more decisively on climate now, we are condemning our descendants to either solving the problem, or facing the consequences.
DAC may have a role in the future, but in the meantime we have to rely on our trees, soil, oceans and wetlands to soak up the carbon we are emitting, even though we have emitted, and are still emitting, too much for them to cope with. So once again, the real immediate need is just to #StopBurningStuff.
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Sources used include:
The Climate Book; Greta Thunberg (Penguin Randomhouse)
The Good Ancestor; Roman Krznaric
The Race Is On film, narrated by James Dyke
Climate Change: the Facts; BBC
Simon Reeve’s Scandinavia; BBC
