Arthur T Knackerbracket has processed the following story:
Microsoft has struck a deal with Heirloom Carbon, a startup that has developed a process for using limestone to capture carbon to fight climate change. The technique could contribute to Microsoft's ongoing attempt to become carbon-negative.
Limestone naturally absorbs carbon over many years, but Heirloom's method accelerates the process. The company uses a kiln powered by renewable energy to heat crushed limestone to around 1,650 degrees Fahrenheit, which separates it into carbon dioxide and calcium oxide. Adding water to the calcium oxide allows it to absorb sufficient amounts of carbon within days, after which Heirloom re-inserts it into the kiln to restart the cycle.
Although the technology is proven, the maximum scale at which it remains cost-effective is unclear. Another issue facing all carbon capture methods is storing the substance.
[...] Regardless of the limestone method's effectiveness, it will likely need to complement other carbon capture technologies that Microsoft is employing to become carbon-negative by 2030. A few years ago, the company also said that by 2050, it wants to remove all of the carbon it has ever emitted since its 1975 founding.