We do not understand the short- and long-term temperature response of soil denitrifiers, which produce and consume N₂O. Boreal forest soils from a long-term climate gradient were incubated in short-term warming experiments. We found stronger N₂O consumption at depth, inconsistent microbial gene abundance and function, and consistent higher N₂O emissions from warmer-climate soils at warmer temperatures. Consideration of our results in models will contribute to improved climate projections.