Projections of surface air temperature required to sustain permafrost and importance of adaptation to climate change in the Daisetsu Mountains, Japan

Toshio Sone,Hiroyuki Oguma,Kazuyuki Saito,Tokuta Yokohata,Noriko N. Ishizaki,Go Iwahana,Masao Uchida,Takahiro Kubo

doi:10.1038/s41598-021-94222-4

Abstract

Permafrost is known to occur in high mountainous areas such as the Daisetsu Mountains in Japan, which are located at the southernmost limit of the permafrost distribution in the world. In this study, areas with climatic conditions suitable for sustaining permafrost in the Daisetsu Mountains are projected using bias-corrected and downscaled climate model outputs and statistical relationships between surface air temperatures and permafrost areas. Using freezing and thawing indices, the size of the area in the Daisetsu Mountains where climatic conditions were suitable for permafrost were estimated to be approximately 150 km2 in 2010. Under the RCP8.5 scenario, this area is projected to decrease to about 30 km2 by 2050 and it is projected to disappear by around 2070. Under the RCP2.6 scenario, the area is projected to decrease to approximately 20 km2 by 2100. The degradation of mountain permafrost could potentially affect the stability of trekking trails due to slope displacement, and it may also have deleterious effects on current alpine ecosystems. It is therefore important to accurately monitor changes in the mountain ecosystem environment and to implement measures to adapt to an environment that is projected to change significantly in the future.

Highlights

Permafrost is known to occur in high mountainous areas such as the Daisetsu Mountains in Japan, which are located at the southernmost limit of the permafrost distribution in the world
By applying the statistical method developed by Satio et al.[52] for estimating the permafrost distribution to outputs from bias-corrected and downscaled climate model with a 1 km resolution[54] for the area of interest, we investigated the climatic conditions required to sustain permafrost in the Daisetsu Mountains
Given that the actual distribution of permafrost is determined by complex interactions between environmental phenomena, such as topography and geology[28], the grid cells classified as permafrost in this study only indicate where the climatic conditions are suitable for the maintenance of permafrost

Summary

Introduction

Permafrost is known to occur in high mountainous areas such as the Daisetsu Mountains in Japan, which are located at the southernmost limit of the permafrost distribution in the world. Areas with climatic conditions suitable for sustaining permafrost in the Daisetsu Mountains are projected using bias-corrected and downscaled climate model outputs and statistical relationships between surface air temperatures and permafrost areas. Using freezing and thawing indices, the size of the area in the Daisetsu Mountains where climatic conditions were suitable for permafrost were estimated to be approximately 150 km[2] in 2010. Under the RCP2.6 scenario, the area is projected to decrease to approximately 20 km[2] by 2100. The thawing of permafrost can have a significant impact on the alpine ecosystem through changes in temperature, soil moisture and groundwater[20,21,22]. There is some concern that the thawing of permafrost will have a major impact on this mountain ecosystem

Objectives

Methods

Results

Conclusion