Ecosystem carbon dioxide emissions are known to be higher in warmer climates, leading to concerns that global warming could accelerate emissions and intensify the greenhouse effect, thereby worsening climate change.
This acceleration only occurs in environments where there is sufficient moisture, according to a study published in Nature Ecology & Evolution by researchers from Stockholm University.
“All organisms need water to live and both plants and soil microorganisms lower their metabolism in dry conditions. As a result, ecosystems release less carbon dioxide when soils are dry,” explained Stefano Manzoni, an associate professor at the Department of Physical Geography, Stockholm University, and co-author of the study.
While most research has focused on temperature’s role in increasing metabolic rates and emissions, this new study emphasizes the critical role of water in this process. It reveals for the first time that there are specific precipitation thresholds necessary to keep soil moist enough to sustain the positive feedback loop from increased ecosystem metabolism.
Once precipitation falls below these thresholds, warming alone will not further increase metabolic rates or exacerbate climate change. These thresholds vary globally, with warmer regions requiring more precipitation to maintain adequate moisture in ecosystems. Therefore, the water cycle plays a crucial role in determining carbon dioxide emissions.
This discovery has significant implications, as many regions may fall short of the necessary precipitation thresholds, making them less responsive to warming because water becomes the most limiting factor.
“To refine our understanding of where and when water becomes limiting, as well as the net impact on carbon dioxide emissions, we need to focus our research efforts on hydroclimate and future water cycle changes,” concluded co-author Jerker Jarsjö, a professor at the Department of Physical Geography, Stockholm University.
Journal Reference:
Zhang, Q., Yi, C., Destouni, G. et al. ‘Water limitation regulates positive feedback of increased ecosystem respiration’, Nature Ecology & Evolution (2024). DOI: 10.1038/s41559-024-02501-w
Article Source:
Press Release/Material by Stockholm University
Featured image: Respiration from dry ecosystems is less sensitive to temperature Credit: wirestock | Freepik
