Herbivores change plant communities through grazing, altering the amount of CO₂ and plant-specific chemicals (termed VOCs) emitted. We tested this effect by excluding herbivores and studying the CO₂ and VOC emissions. Herbivores reduced CO₂ emissions from a meadow community and altered VOC composition; however, community type had the strongest effect on the amount of CO₂ and VOCs released. Herbivores can mediate greenhouse gas emissions, but the effect is marginal and community dependent.