Decadal warming and increased precipitation interactively affect N2O emissions based on a long-term field experiment and a meta-analysis

Abstract

Global warming and altered precipitation affect nitrous oxide (N2O) emissions from terrestrial ecosystems; however, the interactive effects of these global change factors on N2O emissions remain unclear. Here, we use data from a decade-long field experiment in an alpine meadow on the Qinghai-Tibetan Plateau and a global meta-analysis to examine how warming (W) and increased precipitation (P) interactively drive N2O emissions. Our field experiment showed that W and P enhanced N2O emissions by 36.2% and 23.9%, respectively. However, P dampened the W effect on N2O emissions, suggesting an antagonistic interaction between the two global change factors. The N2O emissions were jointly regulated by edaphic properties (such as soil moisture content, temperature and pH) and denitrifying microbial communities, with soil denitrifiers (particularly nirS abundance and community composition) driving N2O fluxes, underscoring the microbial mechanisms regulating N2O emissions under climate change. The meta-analysis, synthesizing 75 observations, revealed that N2O emissions were enhanced by W (+4.5%), P (+18.6%) and WP (+9.4%). Our findings indicate that W and P exhibit positive feedbacks to climate change and the interactive effects of W and P call for more multi-factor experiments to provide data for improving Earth system models to better assess climate change effects on future greenhouse gas fluxes. Read the free Plain Language Summary for this article on the Journal blog.