Given the difficulty and cost of avoiding the emission of greenhouse gases, there has long been interest in an alternative approach—pulling it back out of the air.

Back in 2009, in an article by Lisa Zyga, we heard about “synthetic trees” that could trap carbon dioxide from the air 1,000 times faster than a real tree. At the time, however, it wasn’t cheap. The early models would have cost $30,000 to build and each unit would only capture the emissions of one ton of carbon dioxide per day—the emissions from roughly 20 cars. And the technology has been slow to evolve.

In 2013, Scientific American author David Biello profiled another kind of carbon-capture technology that would capture carbon dioxide from the air, but again, at levels far too low to be taken seriously as a remedy to climate change. The technology could sequester 700 kilograms of carbon dioxide per day, which, as the article observes, is about as much as 13 people exhale over 24 hours. You’d need a heck of a lot of such units to make a dent in atmospheric concentrations of carbon dioxide.

But things seem to be heating up in the air capture space. In 2018, an article in Science observed, “Cost plunges for capturing carbon dioxide from the air.” The 2018 article estimated the cost of air capture could soon drop to $100 per ton captured—that’s a cost comparable to many regulatory measures that are aimed at preventing emissions—taking valuable economic activity with them.

Now, some serious money is flowing into the air-capture sphere. Chevron Corporation and Occidental Petroleum Corporation are investing in an air capture facility in Squamish, British Columbia. The privately owned facility, Carbon Engineering Ltd., has some heavy-hitting shareholders such as Murray Edwards and the ultimate tech whale, Bill Gates. A commercial scale plant of this technology, would:

…scrub 1 megaton of CO2 from the atmosphere per year and occupy 30 acres of land. Oldham said the facility would be the equivalent of planting 40 million trees

Now that’s a lot of people’s exhalations. And, the carbon dioxide captured would have a market value, for use in enhanced oil recovery, and as an additive to jet fuel. I have long championed increased funding for fundamental R&D in the air-capture space, so I have to agree with Gates on this one:

“To stop the planet from getting substantially warmer, we need breakthroughs in how we make things, grow food, and move people and goods—not just how we power our homes and cars,” Gates said in a blog in October.

This surely is a bright spot in the way we think about reducing carbon dioxide concentrations in societies such as Canada, which need vast quantities of energy to maintain our quality of life. To paraphrase Blood Sweat & Tears—what goes up, can come down.