(CNN) Scientists have found a way to suck the carbon pollution that’s heating the planet out of the air, turn it into sodium bicarbonate, and store it in the oceans, according to a new publication.
The technique could be up to three times more efficient than current carbon capture technology, say the authors of the study, published Wednesday in the journal Science Advances.
Tackling the climate crisis means drastically reducing the burning of fossil fuels, unleashing pollution on the planet. However, because humans have already pumped so much of this pollution into the atmosphere and are unlikely to reduce emissions enough in the near future, scientists say we need to remove it from the air, too.
Nature is doing this – forests and oceans, for example, are valuable carbon sinks – but not fast enough to keep up with human production. So we turned to technology.
One method is to capture the CO2 pollution directly at the source, for example in steel or cement works.
But another avenue this study focuses on is “direct air capture”. It involves sucking carbon pollution straight out of the atmosphere and then storing it, often by injecting it into the ground.
The problem with direct air capture is that while carbon dioxide can be a very effective gas for heating the planet, its concentrations are very small — it makes up about 0.04% of the air. That means it’s difficult and expensive to remove directly from the air.
It’s a “significant hurdle,” Arup SenGupta, a Lehigh University professor and study author, told CNN.
Even the largest plants 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 company’s largest facility, capable of capturing up to 4,000 tons of carbon dioxide per year. That corresponds to the CO2 pollution caused by less than 800 cars over the course of a year.
The new technique presented in the study can help address these issues, SenGupta said.
The team used copper to modify the absorbent material used in direct air sensing. The result is an absorbent “that can remove CO2 from the atmosphere at an ultra-dilute concentration with a capacity two to three times greater than existing absorbents,” SenGupta said.
This material is easy and inexpensive to produce and would help reduce the cost of direct air capture, he added.
Once the carbon dioxide is captured, it can be converted with seawater into sodium bicarbonate – baking soda – and released into the ocean in small concentrations.
The oceans “are infinite things,” said SenGupta. “If you dumped all the CO2 from the atmosphere that’s emitted every day — or every year — into the ocean, the increase in concentration would be very, very small,” he said.
SenGupta’s idea is that direct air capture facilities can be built offshore, giving them access to abundant seawater for the process.
Stuart Haszeldine, Professor of Carbon Capture and Storage at the University of Edinburgh, who was Not involved in the study, CNN said the chemistry was “novel and elegant.”
The process is a modification of an already known process, he said, “which is easier to understand, extend and develop than something entirely new.”
But there may be regulatory hurdles to overcome. “Disposing of large quantities of sodium bicarbonate at sea could be legally defined as ‘dumping’, which is prohibited by international treaties,” Haszeldine said.
Others remain concerned about the negative impact on oceans, already stressed by climate change, pollution and other human activities.
Peter Styring, a professor of chemical engineering and chemistry at the University of Sheffield, told CNN: “Unless you have a full ecotoxicity study, you don’t know what it’s going to do, even at low concentrations.”
Direct air capture also remains expensive and inefficient, Styring said. “That is a big problem. Why capture from the atmosphere when there is so much escaping from power plants and industrial plants? It just makes sense to go for the high levels first,” he said.
Some scientists have expressed concern that a focus on technology to eliminate carbon pollution might distract from policies to reduce fossil fuel burning or give polluters permission to continue polluting.
However, given the scale of the climate crisis, there is a lot of pressure from governments and international bodies to scale up this technology.
More research is needed to understand how the method works on a large scale, Haszeldine said. But it shows promise, he added, saying, “The world needs a lot of these kinds of discoveries.”
SenGupta said the technology is ready to be taken out of the lab and tested. “This is the time to go forward and do something in maybe two or three different places around the world. Let other people step in, find bugs, fix them, and then act accordingly,” he said.