When it comes to greenhouse gases, carbon dioxide tends to steal the spotlight—but new research in the journal Proceedings of the National Academy of Sciences (PNAS) reveals how scientists have developed a new, predictive tool to estimate nitrous oxide (N2O) emissions from rivers and streams around the world. N2O, a greenhouse gas with 300 times the warming potential of carbon dioxide, persists for over a century in the Earth’s atmosphere and is known to cause significant damage to the Earth’s ozone layer. Rivers and streams can be sources of N2O because they are hotspots for denitrification, a process whereby microbes convert dissolved nitrogen into nitrogenous gas.