The biogeophysical impacts of land cover changes in Northern Hemisphere permafrost regions

Abstract

The permafrost zone in the Northern Hemisphere has experienced substantial land cover changes (LCCs) in recent decades, resulting in significant impacts on climate and ecosystems by regulating land–atmosphere interactions, energy, water fluxes, and carbon exchange. However, the response of LCCs to climate change is highly variable, especially in terms of biogeophysical effects in high latitude regions. The goal of this study therefore is to quantify the biogeophysical effects of LCCs in Northern Hemisphere permafrost regions. We combine land cover and climate data and separate natural and biogeophysical impacts of LCCs to estimate the contribution on the surface and shallow soil temperatures. From 2001 to 2020, approximately 26 % of the permafrost zone experienced LCCs. LCCs caused a decrease in albedo (−0.15 ± 1.03 %) and an increase in snow depth (2.04 ± 31.96 cm), evapotranspiration (2.19 ± 11.37 mm), and surface heat flux (0.09 ± 1.36 W/m2), resulting in an increase in temperatures: 0.03 ± 0.42 K (surface temperature), 0.07 ± 0.46 K (0–10 cm soil temperature), 0.07 ± 0.45 K (10–100 cm soil temperature), and 0.06 ± 0.43 K (100–200 cm soil temperature), which could increase the risk of permafrost degradation. Seasonally, LCCs exacerbate the temperature difference between winter and summer. Albedo dominates surface temperature changes, with about 87.5 % of surface temperature changes coinciding with albedo changes. Soil temperatures are regulated by snowpack and surface heat fluxes, in addition to albedo.