Protection of Permafrost Soils from Thawing by Increasing Herbivore Density

Christian Beer,Johan Olofsson,Sergey Zimov,Nikita Zimov,Philipp Porada

doi:10.1038/s41598-020-60938-y

Abstract

Climate change will cause a substantial future greenhouse gas release from warming and thawing permafrost-affected soils to the atmosphere enabling a positive feedback mechanism. Increasing the population density of big herbivores in northern high-latitude ecosystems will increase snow density and hence decrease the insulation strength of snow during winter. As a consequence, theoretically 80% of current permafrost-affected soils (<10 m) is projected to remain until 2100 even when assuming a strong warming using the Representative Concentration Pathway 8.5. Importantly, permafrost temperature is estimated to remain below −4 °C on average after increasing herbivore population density. Such ecosystem management practices would be therefore theoretically an important additional climate change mitigation strategy. Our results also highlight the importance of new field experiments and observations, and the integration of fauna dynamics into complex Earth System models, in order to reliably project future ecosystem functions and climate.

Highlights

Human societies currently emit more than 10 Gt carbon (Gt C) every year into the atmosphere in form of carbon dioxide[1] which is a long-lived greenhouse gas (GHG)
The JSBACH model agrees with a conservative global-scale increase in permafrost temperature of 0.7 °C during 1980-2010 (Supplementary Information Fig. S6)
Mean annual ground temperature will be above the freezing point in many contemporary permafrost regions, which translates into an enormous loss of gelisol extent in line with other model results[8,9]

Summary

Introduction

Human societies currently emit more than 10 Gt carbon (Gt C) every year into the atmosphere in form of carbon dioxide[1] which is a long-lived greenhouse gas (GHG). In order to address these questions, here we use snow depth and soil temperature observations in concert with the land surface model JSBACH that is state-of-the-art in terms of process representations for cold regions[20,21]. In addition to the control model experiment (CNTL), a modified version of JSBACH (PlPark experiment) has been run during 2020–2100 In this experiment, the snow compaction rate and the maximum snow density were set at higher values, emulating the effect of winter grazing activities of herbivores, based on observations from Northern Sweden and the Kolyma river lowland in Siberia (methods sections)

Methods

Results

Conclusion