Billions of tons of cement is used each year, which adds billions of tons of planet-warming emissions to the atmosphere.
Photographer: Asim Hafeez/BloombergBoston-based startup Sublime Systems has raised $40 million to develop a new technology to produce low-carbon cement.
The cement industry contributes as much as 8% to global emissions of planet-warming carbon dioxide. Meeting global climate goals under the Paris Agreement would require reducing that to zero within decades.