Concrete is the most widely used material in the world, but it also has a huge carbon footprint. The production of portland cement, the main ingredient of concrete, releases a lot of carbon dioxide into the atmosphere. How can we make concrete more sustainable and climate-friendly? In this article, Wil Srubar, a professor of civil engineering at the University of Colorado Boulder, explores four innovative ways to clean up the concrete industry. He also shares his own research on using algae to produce limestone for cement, which could eliminate 60% of the emissions associated with cement manufacturing. Read on to learn more about the challenges and opportunities of decarbonizing concrete.