image: The left graph illustrates the temporal variations in CH₄ and N₂O emissions from China's natural terrestrial ecosystems over the past four decades. The net GWP remains relatively stable, driven by increasing CH₄ uptake and N₂O emissions. The right map shows the spatial distribution of cumulative global warming potential (GWP) from CH₄ and N₂O emissions in China's natural terrestrial ecosystems from 1980 to 2020. Significant sources are observed in Northeast and South China, while weak sources and sinks are found in North China and the Tibetan Plateau.
Credit: ©Science China Press
China's natural terrestrial ecosystems (NTEs), including forests, grasslands, shrubs and wetlands, play a crucial role in the global methane (CH₄) and nitrous oxide (N₂O) budgets. These ecosystems are both sources and sinks of these potent greenhouse gases, which have a significant impact on global warming. A new study, led by Dr. Tingting Li from the Chinese Academy of Sciences, provides a comprehensive review of CH₄ and N₂O emissions and uptake in China's NTEs over the past four decades.
The study, published in National Science Review, reveals that China's NTEs were significant sources of CH₄ and N₂O emissions between 1980 and 2020, with an accumulated global warming potential (GWP) of 5.55 Pg CO₂-equivalent. The research team used a multi-model approach to estimate CH₄ emissions from natural wetlands, CH₄ uptake from forests, grasslands, and shrublands, and N₂O emissions from these ecosystems. The findings show that while CH₄ uptake by forests, grasslands and shrublands nearly offsets CH₄ emissions from wetlands, the net warming effect is primarily driven by N₂O emissions.
The study also highlights the impact of climate change and land-use changes on greenhouse gas emissions. Rising temperatures and increased precipitation have enhanced CH₄ emissions from wetlands, while atmospheric nitrogen deposition has driven increases in N₂O emissions. Human activities, such as wetland conversion and forest expansion, have also significantly influenced the spatiotemporal patterns of greenhouse gas emissions.
Dr. Li and her team emphasize the need for integrated planning in ecosystem restoration projects to minimize non-CO₂ emissions. They recommend prioritizing grassland restoration in regions like Inner Mongolia and the Tibetan Plateau, where it can enhance CH₄ uptake and contribute to biodiversity conservation. Wetland restoration should focus on areas with low CH₄ fluxes, such as coastal wetlands, to balance greenhouse gas emissions with ecosystem services like water purification and flood control.
This study provides a clearer understanding of the spatiotemporal patterns of CH₄ and N₂O emissions in China's NTEs and offers valuable insights for policymakers aiming to mitigate greenhouse gas emissions while promoting sustainable land use practices.
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See the article:
Methane and nitrous oxide budget for Chinese natural terrestrial ecosystems
https://doi.org/10.1093/nsr/nwaf094
Journal
National Science Review