Scenario-based modelling of carbon storage and sequestration using InVEST model in Kolkata, India, and its environs

Abstract

Assessment of urban carbon balance is imperative to address anthropogenic climate change. Biotic sequestration by urban vegetation and soil boosts terrestrial carbon storage and helps in maintaining the balance. However, unplanned urbanization in developing nations has caused an alarming loss of stored carbon. This study aims to quantify the spatio-temporal change in carbon storage for past, present, and future scenarios in Kolkata and its surroundings using the InVEST (Integrated Valuation of Ecosystem Services and Trade-offs) model. Four plausible future scenarios were simulated using a two-axis scenario analysis, based on two major drivers of urban sustainability: economic growth and restoration of UGS (urban green space). Each simulated scenario corresponds to the presumptive narrative of a 10% change in the LULC (land-use land-cover). The findings indicate a substantial loss of stored carbon (2.03 Tg) with a valuation of $ 410 million from 1992 to 2022. Notable reduction of carbon storage can be detected in the eastern and southern periphery, in a 10–15 km radius from the center of the city. This loss is mostly attributed to the emergence of key urban growth centers, characterized by large-scale infrastructural development. Compared to 2022, total carbon storage decreased by 10–15% in scenarios directed by economic development (least focus on UGS restoration), whereas it increased by 21% when UGS were restored. The methodology combines scenario analysis with carbon storage modelling, providing researchers and urban planners with valuable insights for proactive policy planning that support healthy urban livelihoods and ecosystems. It also helps in assessing the importance of urban vegetation and soil as natural carbon sinks.