A geospatial approach to assess climate change impact on soil organic carbon in a semi-arid region

Abstract

The changes in the atmosphere and climate influence soils by disturbing the functioning of hydrologic and biogeochemical cycles, specifically that of Carbon (C). The impact of the climatic change on soil organic carbon (SOC) stocks over a semi-arid region of India (Medak district, Telangana) was assessed using remote sensing-based indices and geostatistical modeling. The global soil organic carbon (GSOC) stocks (0–30 cm depth) at 1 km spatial resolution and a set of environmental variables like Normalized difference vegetation index (NDVI), Net primary productivity (NPP), slope, elevation and various climate parameters such as rainfall, temperature, etc., were used to estimate the SOC stocks in current and future (2050 and 2070) climate change projections using regression kriging (RK) technique. The results of the study indicate that among the environmental covariates rainfall was the predominant factor that controls the SOC stocks in the study region. The current SOC stock in the study area was estimated as 25.4 Tg in top 0–30 cm depth. The future (2050 and 2070) SOC stocks were predicted using climate parameters of three Global Circulation Models (GCMs); namely CCSM4, HadGEM2-AO, and HadGEM2-ES. Results show a reduction in SOC stocks in 2050 and 2070 due to the projected climate change in the study region. The projected decrease in total SOC stocks varies from 1.12 to 4.93 and 0.45 to 4.49 Tg by 2050 and 2070 respectively. The uncertainty associated with the prediction of the current stock of SOC was 8.44%. The uncertainties associated with the SOC prediction in various future climate change scenarios for the year 2050 and 2070 were in the range of 8.83–10.48% and 8.15–10.26% respectively.