Scrubbing carbon dioxide from the air is imperative if humanity is to limit global warming, experts say, and a California startup says it can do just that, using limestone as a carbon-sucking sponge.

San Francisco-based Heirloom Carbon has become a hot name in the nascent capture technology sector, even sealing a deal with Microsoft to help the Windows-maker meet its zero-carbon ambitions.

Governments are embracing similar innovations to meet their climate goals as CO2 emissions remain too high to mitigate the greenhouse effect that causes the devastation of climate change.

Capturing CO2 directly out of the atmosphere is the “time machine” that will take us back to cleaner air, according to Heirloom cofounder and CEO Shashank Samala.

“If you actually want to reverse climate change and go back to where things were, carbon removal is the closest thing we have actually removing legacy emissions from the air,” he said.

Carbon capture will be a central topic of discussions at the COP28 climate talks, which take place in Dubai from November 30 to December 12.

Many see it as a necessity to get closer to a zero-emission world while others fear it is being hailed as an easy ticket to avoid making the sacrifices needed to slow climate change.

The UN Panel on Climate Change (IPCC), which steers the COP meetings, considers the deployment of carbon capture and storage systems to be unavoidable if we are to limit global warming to 1.5 degrees Celsius above pre-industrial levels.

Heirloom has set itself the goal of ridding the atmosphere of one billion tonnes of CO2 per year by 2035 — without incentivising companies to keep burning fossil fuels.