Climate change projections of terrestrial primary productivity over the Hindu Kush Himalayan forests

Increasing atmospheric carbon dioxide concentration [CO2] caused by anthropogenic activities has triggered a requirement to predict thefuture impact of [CO2] on forests. The Hindu Kush Himalayan (HKH) region comprises a vast territory including forests, grasslands,farmlands and wetland ecosystems. In this study, the impacts of climate change and land-use change on forest carbon fluxes and vegetationproductivity are assessed for HKH using the Lund–Potsdam–Jena General Ecosystem Simulator (LPJ-GUESS). LPJ-GUESS simulations were driven by anensemble of three climate models participating in the CMIP5 (Coupled Model Intercomparison Project phase 5) database. The modelled estimates ofvegetation carbon (VegC) and terrestrial primary productivity were compared with observation-based estimates. Furthermore, we also explored the netbiome productivity (NBP) and its components over HKH for the period 1851–2100 under the future climate scenarios RCP2.6 and RCP8.5. A reducedmodelled NBP (reduced C sink) is observed from 1986–2015 primarily due to land-use change. However, an increase in NBP is predicted under RCP2.6 andRCP8.5. The findings of the study have important implications for the management of the HKH region, in addition to informing strategic decision making and land-use planning, and clarifying policy concerns.