How To Build A Climate-Friendly Skyscraper: Start Petri-Dish Small.

Prometheus Materials has a solution for replacing one of the biggest contributors of greenhouse gasses, financial backing from Microsoft and an aggressive plan to scale up quickly.

_{By Amy Feldman, Forbes Staff}

We love concrete. We use it everywhere — skyscrapers, data centers, roofs, sidewalks, homes. The problem is, concrete doesn’t love us. Its key ingredient, cement, is the source of 8% of the world’s emissions of carbon dioxide, a gas that’s catastrophically warming the planet. But how do we replace a material that’s so inexpensive, so durable and so popular?

Prometheus Materials has an intriguing answer. The University of Colorado spinout is turning algae into cement using a process that’s similar to how coral and seashells naturally form. “Climate change is potentially an existential problem, and we’re finding that nature may have provided us with the keys to a solution,” says Loren Burnett, the company’s cofounder and CEO.