"There's not much left in the coffers, so it's high time we change course and get to grips with our carbon economy, reduce our consumption and bring things in balance!”

These words are spoken by Lars Ditlev Mørck Ottosen, professor and CORC group leader, who compares the carbon balance with our economy: if we’ve used up our credit, then it’s time to pay up. And one way we can do that is by removing a significant amount of the CO₂ we’ve emitted into the atmosphere.

He was on stage at the Tech Tent at Engineer the Future together with Ulrich Bang, deputy director of the Danish Chamber of Commerce and responsible for climate, energy and the environment, and moderator Lotte Folke Kaarsholm, managing editor of the Opinion section of the Danish newspaper Politiken. Under the heading “Are giant CO₂ vacuum cleaners a part of our future?” , the debate centred on the fact that we’ve exceeded our credit limit. Fixing this will require very drastic emission reductions. However, we’re well past the point of this being enough. We must therefore also look at other ways of reducing the huge amounts of CO₂ we have emitted into the atmosphere, which is currently heating our planet at an alarming rate.

"In the short term, we must first and foremost reduce our emissions. It’s much cheaper than paying the expensive interest rates on our credit limit. This is why priority number one is to do everything we can to reduce emissions and reduce over-consumption as quickly as possible," says Lars Ditlev Mørck Ottosen.

Unfortunately, we have reached a point where we cannot hope to stay below the 1.5 degrees limit set by the Paris Agreement with reductions alone; we must develop methods to pull CO₂ out of the atmosphere.

And according to Lars Ditlev Mørck Ottosen, we must do what we can to stay under the limit to avoid some of the most serious repercussions:

“Exceeding the limit would be the dumbest pay-day loan of all!”

Lars Ditlev Mørck Ottosen stresses that CO₂ capture with Direct Air Capture and other technologies to pull CO₂ out of the atmosphere might distract us from reducing emissions.

"The debate about CO₂ capture can be dangerous, as it can become a pretext for inaction that pulls attention away from the fact that we have to reduce our emissions. I’d prefer avoiding CO₂ capture completely because it’s not easy nor proactive. But unfortunately, it doesn't look like we can avoid it,” he says.

Vacuum cleaner with Direct Air Capture?

It wasn’t that long ago that CO₂ capture was considered pure science fiction and a bit of an oddity because many believed the technology would take too long to develop compared with the speed of temperature increases and climate change.

But is it possible to capture CO₂ directly from the atmosphere, and can it help solve the biggest crisis of our age?

"It's not impossible, and an increasing number of start-ups are looking at Direct Air Capture technologies. But it’s an enormous task, on the same scale as the transition of other parts of our energy system. Maturing the technology also requires more research and investment in test facilities, so we can make sure the technology is ready to be put into use once it’s really needed,” says Lars Ditlev Mørck Ottosen.

Illustration of the principle of CO2 capture from the atmosphere

Imagine building a vacuum cleaner to capture CO2. The inside of the vacuum cleaner bag must be clad with a material that is particularly good at binding CO2, thus ensuring that the CO2 ‘sticks’ to the material. You then use energy to suck in atmospheric air with CO2 until the bag is full, which can take a long time when the concentration is relatively low. The CO2 then gets stuck inside the bag, and in order to get rid of it again, more energy needs to be used. An engine is needed to suck in the CO2 and a huge amount of energy is necessary when emptying the bag to release the CO2.

“As researchers, we’re interested in how we can make things better, more efficient and scalable. There’s considerable research potential in this, but the development, industrialisation and production of the technology will require enormous effort. It’ll also require huge amounts of energy," explains Lars Ditlev Mørck Ottosen.

It has potential, but is not a quick fix

Even though CO₂ levels in the atmosphere are at an all time high, the numbers are still relatively low, i.e. only a little more than 0.041 per cent. This makes it difficult to pull CO₂ directly out of the atmosphere. So even though it sounds easy, it's not.

Lars Ditlev Mørck Ottosen does not think it is a good idea to use the limited amount of renewable energy currently available for technologies like Direct Air Capture. Regardless of which solution we imagine might be able to capture CO₂ from the atmosphere in the quantities necessary, it will require a huge amount of energy because of large volume of CO₂ needed to be captured.

"To give an idea of the magnitude we’re dealing with, to capture just 15 per cent of current global emissions, we’d have to use all the renewable solar, wind and water energy that we have at our disposal. That’s not a quick fix!” he stresses.

According to the researcher, reducing CO₂ levels in the atmosphere will take decades, and will be achieved by a slow stabilisation and reduction of CO₂ in the atmosphere via technological solutions and via society significantly reducing the amount of greenhouse gases it emits.

Carbon as a business case

The two debaters both believe we need to begin thinking of CO₂ as a valuable resource.

"CO₂ is a very useful molecule, it’s present in everything around us. Our plants feed on it and our world is built around it. Carbon economy and CO₂ are vital to us and our economy. The only problem with CO₂ is that we have too much of it in the atmosphere," says Lars Ditlev Mørck Ottosen.

We can do two things with the CO₂ we capture; we can store it, so it is no longer harmful, or we can use it as a circular product, e.g. a green fuel, that contributes to phasing out fossil sources. With this kind of thinking, CO₂ - including the CO₂ captured from the atmosphere – will become a high-value commodity.

Accelerating technologies such as Direct Air Capture and developing business models to manage CO₂ will require both regulation and political support. It will also require making the prospect attractive to business and industry. 

Ulrich Bang, deputy director of climate, energy and the environment at the Danish Chamber of Commerce, believes political regulation in the form of a green tax is needed if sustainable business models for CO₂ as a commodity are to be developed.

"There needs to be a price on CO₂. We should pay for the CO₂ we emit in the same way we pay taxes to have our wastewater and garbage taken care of. This is foundational for the innovation and development of business models. As things stand, it’s completely free in many places to emit CO₂ and pollute, and there’s no business model. Which is why putting a price on CO₂ is crucial," he explains.

Ulrich Bang mentions a specific example, a bio-based t-shirt made of sap from grass:

"A t-shirt like this could have used polyester from oil. Instead, it’s made of sap from grass, which saves two kilos CO₂ compared to traditional production methods. Recirculating CO₂ brings a lot of commercial opportunities into play," he explains.

Grass jersey presented at Folkemødet designed by Danish fashion designer Henrik Vibskov and fabric produced by the Danish company Pond Biomaterials.

What are the biggest barriers?

The Danish Chamber of Commerce finds that many companies are very committed to creating green solutions, including solutions based on CO₂. However, it also requires a certain amount of regulation on the part of public authorities.

"The climate challenges are solved by companies inventing innovative solutions that make the world a better place. And that they can make a profit on. But regulation is also needed so we can ensure the right framework conditions," explains Ulrich Bang.

Even though many believe that CO₂ capture on an industrial scale is necessary to meet the targets set by the Paris Agreement, we have not yet discovered any viable and scalable solutions. So what are the biggest barriers standing in our way?

"Firstly, it’s important that there’s research support at the universities. Basic research is actually important. And, of course, companies have to be brought into play as well," says Ulrich Bang.

He sees great potential in capturing and using CO₂, but warns that we should avoid falling into the trap of thinking that it’s the only option for doing this:

"There won't just be one single technology that wins the race, we should focus on many different technologies. It was the same case back when the wind turbine industry was in its infancy; multiple options were being considered simultaneously. There exist many exciting and innovative solutions, and we have to dare to believe in the power of innovation. And we must dare to not choose the first and most familiar technologies," he concludes.

Finally, Lars Ditlev Mørck Ottosen stresses that our main priority should be reducing our emissions, but that there’s also a need for more investment in developing technologies to capture CO₂ from the atmosphere:

“It’s about taking charge of our carbon economy and of where the CO₂ we use comes from. And we need to start testing technologies such as Direct Air Capture on a larger scale than today, so we can learn more and develop the technology. This requires a certain degree of investment readiness."