(CNN) Scientists have developed a way to suck planet-warming carbon pollution from the air, turn it into sodium bicarbonate, and store it in the oceans, according to a new paper.
The technique could be up to three times more efficient than current carbon capture technology, believe the authors of the study, published Wednesday in the journal Science Advances.
Dealing with the climate crisis means drastically reducing the consumption of fossil fuels, a source of pollution that warms the planet. But because humans have already pumped much of this pollution into the atmosphere and are unlikely to reduce emissions enough in the near term, scientists say we need to get it out of the air too. .
Nature is doing this – forests and oceans, for example, are valuable carbon sinks – but not fast enough to keep pace with the amounts produced by humans. So we turned to technology.
One method consists in capturing carbon pollution directly at the source, for example that of steel works or cement works.
But another way, which this study focuses on, is “direct air capture.” This involves sucking carbon pollution directly from the atmosphere and then storing it, often by injecting it into the ground.
The problem with direct air capture is that although carbon dioxide can be a very potent gas for heating the planet, its concentrations are very low – it makes up about 0.04% of the air. This means that it is difficult and expensive to remove it directly from the air.
It’s a “significant hurdle,” Arup SenGupta, a Lehigh University professor and study author, told CNN.
Even the largest facilities can only remove relatively small amounts and it costs several hundred dollars to remove each ton of carbon.
Climeworks’ direct air removal project in Iceland is the largest facility, according to the company, and can capture up to 4,000 tonnes of carbon dioxide per year. This is equivalent to the carbon pollution produced by less than 800 cars in a year.
The new technique shown in the study can help address these issues, SenGupta said.
The team used copper to modify the absorbent material used in direct air capture. The result is an absorbent “that can remove CO2 from the atmosphere at ultra-dilute concentration at a capacity that is two to three times greater than existing absorbents,” SenGupta said.
This material can be produced easily and cheaply and would help reduce direct air capture costs, he added.
Once the carbon dioxide is captured, it can then be converted into sodium bicarbonate (baking soda) using seawater and released into the ocean at a low concentration.
The oceans “are infinite sinks,” SenGupta said. “If you dump all the CO2 in the atmosphere, emitted every day – or every year – into the ocean, the increase in concentration would be very, very minor,” he said.
SenGupta’s idea is that direct air capture plants can be located offshore, giving them access to copious amounts of seawater for the process.
Stuart Haszeldine, professor of carbon capture and storage at the University of Edinburgh, who was not involved in the study, told CNN the chemistry was “new and elegant.”
The process is a modification of the one we already know, he said, “which is easier to understand, scale and develop than something totally new.”
But there may be regulatory hurdles to overcome. “The release of large tonnages of sodium bicarbonate into the ocean could be legally defined as ‘dumping,’ which is prohibited by international treaties,” Haszeldine said.
Others remain concerned about the negative impacts on the oceans, which are already under pressure from climate change, pollution and other human activities.
Peter Styring, professor of chemical engineering and chemistry at the University of Sheffield, told CNN: “Unless you have a full ecotoxic study, you don’t know what it’s going to do, even at small concentrations. .”
Direct air capture also remains expensive and inefficient, Styring said. “It’s a large-scale problem. Why would you capture from the atmosphere when you have so much coming out of power plants and industrial plants? It makes sense to go for the high concentrations first,” did he declare.
Some scientists have expressed concern that the focus on technology to eliminate carbon pollution could distract from policies aimed at reducing the burning of fossil fuels or giving polluters the right to continue polluting.
But given the scale of the climate crisis, governments and international bodies are scrambling to develop this technology.
More research will be needed to understand how the method works on a large scale, Haszeldine said. But it’s promising, he added, saying “the world needs a lot of this kind of discovery.”
SenGupta said the technology is ready to roll out of the lab and be tested. “Now is the time to move on and do something in maybe two or three different places in the world. Let other people get involved, find flaws, improve, and then move on. accordingly,” he said.