Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. Concrete is everywhere, and that’s a problem. Manufacturing the essential material accounts for around eight percent of annual global carbon dioxide emissions, making it one of the single biggest contributors to the climate crisis. Researchers are investigating all types of creative solutions to the issue, often by replacing ingredients with more eco-friendly alternatives. Recent propositions include adding coffee grounds, bacteria, and even recycled diapers into the mix.But engineers at Purdue University in Indiana think the answer can already be found in the natural world. According to a study recently published in the journal Chemistry of Materials, one solution may be swapping out the cement for shellfish. “Oysters generate a natural cement. They use this material for attaching to each other when building reef structures,” chemist and study co-author Jonathan Wilker explained in a recent university profile. Wilker has spent years examining the biological properties of oyster cement in hopes of recreating the sturdy adhesive for other applications. They have …