Abstract
Abstract. We use a soil carbon (C) model (RothC), driven by a range of climate models for a range of climate scenarios to examine the impacts of future climate on global soil organic carbon (SOC) stocks. The results suggest an overall global increase in SOC stocks by 2100 under all scenarios, but with a different extent of increase among the climate model and emissions scenarios. The impacts of projected land use changes are also simulated, but have relatively minor impacts at the global scale. Whether soils gain or lose SOC depends upon the balance between C inputs and decomposition. Changes in net primary production (NPP) change C inputs to the soil, whilst decomposition usually increases under warmer temperatures, but can also be slowed by decreased soil moisture. Underlying the global trend of increasing SOC under future climate is a complex pattern of regional SOC change. SOC losses are projected to occur in northern latitudes where higher SOC decomposition rates due to higher temperatures are not balanced by increased NPP, whereas in tropical regions, NPP increases override losses due to higher SOC decomposition. The spatial heterogeneity in the response of SOC to changing climate shows how delicately balanced the competing gain and loss processes are, with subtle changes in temperature, moisture, soil type and land use, interacting to determine whether SOC increases or decreases in the future. Our results suggest that we should stop looking for a single answer regarding whether SOC stocks will increase or decrease under future climate, since there is no single answer. Instead, we should focus on improving our prediction of the factors that determine the size and direction of change, and the land management practices that can be implemented to protect and enhance SOC stocks.
Highlights
Soils contain the largest pool of the terrestrial carbon (C)
In the past, human-induced land use change has caused a significant loss of soil organic carbon (SOC) with global estimates ranging between 40–537 Pg C (Lal, 2003)
Our study suggests that SOC stocks in 2100 show a slightly higher variability, due to using predictions from different atmosphere-ocean global circulation model (AOGCM) interpreting one emission scenario, rather than using one AOGCM interpreting a range of SRES scenarios
Summary
Soils contain the largest pool of the terrestrial carbon (C). In the past, human-induced land use change has caused a significant loss of soil organic carbon (SOC) with global estimates ranging between 40–537 Pg C (Lal, 2003). Due to its large size and long residence time, SOC can act as a large sink of atmospheric C (Post et al, 1982; Smith, 2004; Lal, 2004). It has been shown that the temperature sensitivity of the global SOC pool has a significant effect on the development of the future climate (Cox et al, 2000;Dufresne et al, 2002; Friedlingstein et al, 2003). P. Gottschalk et al.: Global SOC projections using RothC
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.