r/science • u/Wagamaga • Feb 13 '25

Chemistry Researchers have developed a reactor that pulls carbon dioxide directly from the air and converts it into sustainable fuel, using sunlight as the power source

https://www.cam.ac.uk/research/news/solar-powered-device-captures-carbon-dioxide-from-air-to-make-sustainable-fuel
4.3k Upvotes

97% Upvoted

255 comments sorted by

View all comments

Show parent comments

90

u/OnlyOneChainz Feb 13 '25

The difference is that you can place this machine anywhere there is sun. To offset the yearly human carbon emissions you'd need to roughly double the forested area of the world. It's just not an realistic option, you'd have to convert massive amounts of farmlands to forest. Theoretically, you could pop this thing down in the desert where no tree would ever grow.

95

u/D-F-B-81 Feb 13 '25

Rooftops of our big city buildings, to suck put as much from the areas that produce the most emissions would be a great place to put them.

And you already have knowledgeable maintenance crews that keep the other rooftop equipment in working order, so this could be a legitimate partial solution.

I hate how people often reject an idea because it doesn't solve the whole equation. These can play a significant role, along with other options in reducing carbon emissions.

9

u/beigechrist Feb 13 '25

This is a good thought, and who knows, maybe a lot of them could help offset the heat sink that cities have in summers.

7

u/noggin-scratcher Feb 14 '25

I would expect that "heat island" effect to be because of the materials used in city construction absorbing/retaining more heat, rather than because of any difference in local CO2 concentration.

0

u/beigechrist Feb 14 '25

It is. I’m just thinking aloud about any smaller effect by the device. Cheers

-3

u/alimanski Feb 13 '25

Unfortunately, the sheer weight of the ground and water needed for the tree makes it not feasible on many rooftops. It means the roof needs to be much stronger, meaning the entire building needs to support it, more concrete and steel, more energy and emissions, more maintenance, more costs...

14

u/Naritai Feb 14 '25

Yes, so let's put in these machines instead

22

u/TheColdWind Feb 13 '25

Check out the Sahel project in Africa. It didn’t work exactly as planned, but did work in very unexpected ways. Smithsonian magazine has an excellent article on it. It basically began as a 10 mile wide, 4300 mile long desert barrier, but wound up being a native land use project that turned vast swaths of African deserts green and allowed for more productive land use by native peoples. It was all done on a shoestring budget with local labor. Very interesting to learn about.

10

u/OnlyOneChainz Feb 13 '25

Yes I know, planting trees in the Sahel is extremely important and a fascinating project. The Chinese government did a similar thing, partly to stop sandstorms from the western deserts to reach the bigger cities to the East. (Chinese green wall). Forests do not only store carbon but have a wide array of benefits, if done correctly (focusing mainly on diverse, native species; proper management techniques etc.)

Agroforestry is another option to possible increase carbon storage in farming areas.

Planting forests can absolutely be part of the solution.

7

u/SirPseudonymous Feb 14 '25

The Chinese government did a similar thing

That project is actually ongoing. It was set up to be this huge 50 year long reforestation campaign and it's still nowhere near complete, although it's been moving faster than originally projected.

The only real problem is that while in some places it's been way more successful than expected and the forest gets wider every year, in other places it's basically just fighting to stand still and replanting the same stretches every year. Fortunately the whole project is also one big research testing ground to identify problems like that and find workable solutions to them, so hopefully they find some way around that.

There are some worries about the ground water cycle in some areas, too, with the trees sequestering water that would have otherwise gone into aquifers and losing enough of it to evaporation that it's gradually depleting said aquifers. But that's a comparatively small price to pay to stop the expansion of the desert.

3

u/TheColdWind Feb 13 '25

Was the Chinese project in the Gobi?

5

u/OnlyOneChainz Feb 13 '25

Yup. They had some initial troubles because they only used one specific poplar clone and some bug found that poplar quite delicious and had a feast but since then they have vastly ramped up the diversity and planted area and I think it has been quite the success.

1

u/TheColdWind Feb 13 '25

Even a dead tree becomes a biodiversity hotspot I think, attracts birds, they drop nutrients, attract insects, etc. I’m going to look into the project later. Tks

2

u/OnlyOneChainz Feb 13 '25

Yes, dead wood is awesome from an ecological standpoint but for carbon storage or wind protection it's obviously not ideal.

1

u/TheColdWind Feb 13 '25

Sure, of course, it’s on its way back to the atmosphere at that point.

13

u/lurkerer Feb 14 '25

We could easily reduce the amount of farmland we use by a huge amount:

In the hypothetical scenario in which the entire world adopted a vegan diet the researchers estimate that our total agricultural land use would shrink from 4.1 billion hectares to 1 billion hectares. A reduction of 75%. That’s equal to an area the size of North America and Brazil combined.

Vegan world -> Less pasture land and arable crop land needed.

Potential benefits:

Restoring ecosystems on just 15 percent of the world’s current farmland could spare 60 percent of the species expected to go extinct while simultaneously sequestering 299 gigatonnes of CO2 — nearly a third of the total atmospheric carbon increase since the Industrial Revolution, a new study has found.

A massive answer staring us in the face, and yet... But hey, people don't want to go vegan. Consider that it would take all of half a year for R&D into lab-grown meat to scale if real meat wasn't allowed. The change to diets would be temporary in exchange for saving the world.

38

u/Zvenigora Feb 13 '25

 Now you just need to make about a trillion of them, and then keep them all maintained and in working order.

38

u/Kain222 Feb 13 '25

I mean, with Climate Change, you can't let perfect be the enemy of good.

Sure, this thing won't slow stuff down on its own, but we should take every single win we can get.

16

u/OnlyOneChainz Feb 13 '25

It depends, since it's technology it could possibly made way more efficient than a tree. I agree this is probably not going to happen though.

14

u/[deleted] Feb 13 '25

[removed] — view removed comment

9

u/twystoffer Feb 13 '25

Given the flow rate and efficiency, more like 100+ trees.

However, this particular experiment was only designed to test the feasibility of solar powered carbon exchange using this particular method.

With some slight tweaks and maybe an introduction of another power source (wind or tidal), you could potentially ramp that up even further.

The biggest issue is that it creates syngas, which breaks down into CO and H if not used, and CO2 if it IS used.

But...

Considering that syngas is a precursor to fertilizer, it might be worth it...

6

u/-Ch4s3- Feb 13 '25

Carbon neutral synthetic gas seems pretty great if it’s commercially viable. If you’re just cycling CO2 out of the air, through combustion, and back into the air then you could replace a lot of things that still couldn’t be battery powered. Synthetic gas for marine fuel could be a huge benefit to overall carbon reduction insofar as it would cut a lot of net emissions.

2

u/twystoffer Feb 13 '25

That's exactly what ethanol is. We have an pretty decent abundance of carbon neutral fuels, but not nearly enough carbon extraction.

2

u/-Ch4s3- Feb 14 '25

Corn ethanol is not in any way carbon neutral. I think something like 40 gallons of diesel go into 1 gallon of corn ethanol production.

-6

u/JBstard Feb 13 '25

I don't think you're going to beat mother nature in efficiency stakes

7

u/Hei2 Feb 13 '25

Mother nature doesn't really care about efficiency; it cares about what works. There are plenty of examples of inefficient design in biology (think the recurrent laryngeal nerve in giraffes, or the optic disc in human eyes).

10

u/irisheye37 Feb 13 '25

Nature has far more variables than the efficiency of a single task.

4

u/Fr00stee Feb 13 '25 edited Feb 13 '25

since corporations only do things if they can make money, some chemical/oil corp would love to be able to put these things everywhere and keep using the output to power gas engines. The only feasible way I see to get these corps to do something that would fix the planet.

2

u/KnottShore Feb 13 '25

The probable case for a chemical/oil corp is to buy an exclusive license and kill the technology.

2

u/Fr00stee Feb 13 '25

there researchers can just patent it then give the ability to use it for free

2

u/bielgio Feb 13 '25

Won't get funding or subsides required

Pay attention, we either have a monopoly or the government to have innovation at scale, right now the richest country in the world has no government

1

u/Fr00stee Feb 13 '25

this is from the UK so idk

1

u/Naritai Feb 14 '25

sure it will, we don't need this kind of doomerism

1

u/klingma Feb 14 '25

Okay? What's the problem though? 

Our issue is that climate change is causing havoc across the Earth and if we can't motivate people to do something about it out of the goodness of their hearts but we can with money, we still accomplish the same end goal, right? 

We don't criticize dogs who follow commands because they want a treat, why would we criticize someone who wants to do something about climate change but also make money? In scenario one the dog sits and in scenario two we get progress fighting climate change. 

0

u/Fr00stee Feb 14 '25 edited Feb 14 '25

there is no problem? I was just saying that it might be a viable solution since companies don't really want to do anything about climate change using current technologies

-2

u/Opie67 Feb 13 '25

Why is it the people that panic and cry about climate change the most are viciously against any real potential solutions

1

u/ThrowbackPie Feb 14 '25

We aren't. But we are very frustrated that our solution is to keep destroying the natural world and replacing it with machines.

2

u/eagee Feb 13 '25

Um, have you never been to the mojave and sonoran deserts? There's a lotta space there with endless supplies of sunshine.

4

u/polypolip Feb 13 '25

You could turn most of the farmlands into forests if humanity stopped breeding cows.

1

u/Naritai Feb 14 '25

Any plan that involves "If everyone would just..." is a stupid plan

4

u/noggin-scratcher Feb 14 '25

If you need 100% participation then sure, such plans are implausible.

But often a statistic like "if everyone would X, then Y" remains true of "if 10% of people would X, then 10% of Y" and the stronger statement is an illustration of the upper limit of potential.

1

u/AlkaliPineapple Feb 14 '25

Or we could just... Strike the source and lower carbon emissions? I have no doubt that the production of these things would release more carbon dioxide than it absorbs