Water scaling of ecosystem carbon cycle feedback to climate warming

Abstract

It has been well established by field experiments that warming stimulates either net ecosystem carbon uptake or release, leading to negative or positive carbon cycle–climate change feedback, respectively. This variation in carbon-climate feedback has been partially attributed to water availability. However, it remains unclear under what conditions water availability enhances or weakens carbon-climate feedback or even changes its direction. Combining a field experiment with a global synthesis, we show that warming stimulates net carbon uptake (negative feedback) under wet conditions, but depresses it (positive feedback) under very dry conditions. This switch in carbon-climate feedback direction arises mainly from scaling effects of warming-induced decreases in soil water content on net ecosystem productivity. This water scaling of warming effects offers generalizable mechanisms not only to help explain varying magnitudes and directions of observed carbon-climate feedback but also to improve model prediction of ecosystem carbon dynamics in response to climate change.

Multiple‐scale negative impacts of warming on ecosystem carbon use efficiency across the Tibetan Plateau grasslands

“…For our targeted alpine ecosystems, K. pygmaea and other shallow‐rooted species inherited low resistance to soil water stress induced by HW, and their growth would be suppressed easily by HW (N. Chen, Zhang, et al., 2019; Ganjurjav et al., 2016; N. Li et al., 2011). Warming effects scale with warming‐induced SM changes, and there normally exists a threshold for this process (Quan et al., 2019). When the aridity level threshold is exceeded, even by a small increment, it can lead to drastic changes in corresponding ecological processes (Berdugo et al., 2020).…”

“…In addition, the SWE CUEe (.46) was close to that of the SSWE (.42) under LW, but larger differences were exhibited under HW. CUEe component responses to LW differ from those to HW (N. Chen, Zhang, et al., 2019; Quan et al., 2019). The negative effects of HW on the influential factors (e.g.…”

“…For example, stronger negative effects of warming on GEP than on ER would decrease CUEe (N. Chen, Zhang, et al., 2019). More importantly, numerous studies have documented the nonlinear responses of GEP and ER to warming, and their sensitivities varied significantly under multiple‐level warming (N. Chen, Zhu, et al., 2019; Quan et al., 2019). This may lead to the nonlinear responses of the CUEe to warming.…”

Navigating transformation of biodiversity and climate

“…Two papers in this collection address the complexity of feedback processes. Quan et al ( 10 ) provides experimental evidence and meta-analyses on ecosystem carbon fluxes and their feedback to warming, whereas Pugnaire et al ( 11 ) review the evidence regarding plant-soil feedback (PSF) under pressures of climate, providing critical insights into the significant role of microbes within the plant-soil food web and how these interactions are reflected in the carbon cycle with measurable consequences for both climate and biodiversity.…”

Influence of Variations of Hydrothermal Conditions on Normalized Difference Vegetation Index in Typical Temperature Zones Along the East Coast of China

“…There is a bidirectional feedback mechanism between the climate and the terrestrial ecosystem: a variation of a hydrothermal condition causes a change in a temporal and spatial distribution pattern of the terrestrial ecosystem (Huang et al, 2016;Huang et al, 2019); and the change of the ecosystem patterns affects a regional carbon cycle and water cycle process, which in turn reacts on the regional climate (Sippel et al, 2018;Quan et al, 2019). Under the background of climate warming, temperature, precipitation, radiation, and other factors in different regions are obviously different, and the influence of the climate change on the vegetation in different regions varies.…”