As frozen soil, called permafrost, increasingly thaws over the years, scientists have put much effort into understanding how this may increase carbon emissions, which would exacerbate climate change. Our work supports the emerging view that these efforts should also include nitrous oxide (N₂O), a more potent greenhouse gas. Using a low-flying aircraft to study thousands of acres of Alaskan permafrost, we observed average N₂O emissions higher than typically assumed for regions such as this.