Spatiotemporal Carbon Valuation in the Eco-Sensitive Areas of the Western Ghats:An InVEST-PLUS Assessment (1992–2020) with 2030 Projections

Abstract India’s Nationally Determined Contribution commits to creating an additional 2.5–3 billion tonnes of carbon sinks by 2030. This study examines carbon storage and sequestration in the Western Ghats (WG) from 1992 to 2020, comparing Ecologically Sensitive Areas (ESAs) and non-ESAs using the Gadgil and Kasturirangan committee reports. Utilising the Carbon Storage and Sequestration module of the “Integrated Valuation of Ecosystem Services and Trade-off” (InVEST) model, we integrated ESA land-cover maps with Forest Survey of India data to estimate biophysical and monetary values of carbon sequestration. A ±10% sensitivity analysis confirms these estimations are highly robust against baseline variations. Findings reveal a net forest increase in the ESA, driven by Karnataka’s gains of 2,042 km² (1992–2015) and 1,134 km² (2016–2020). However, this coincided with significant evergreen forest losses in Kerala (132 km²) and Tamil Nadu (558 km²) during 1992–2015. Conversely, non-ESAs of Maharashtra, Gujarat, and Karnataka saw net forest losses before recovering during 2016–2020. The ESA gained sequestration benefits worth $1,135 (at 7% Social Discount Rate (SDR)) –$1,225 million (at 3% SDR) (1992–2015) and $1,080 million (2016–2020). While non-ESAs initially lost $109.9 million (at 7% SDR) –$115.69 million (at 3% SDR), they received $984.13 million during the latter period. The 2030 PLUS-InVEST simulation projects an additional economic value of $1.38–$1.61 billion under the business-as-usual scenario. The ESAs recorded higher CSn per km² and economic benefits than the non-ESAs during the study periods. These findings highlight the higher observed carbon sequestration per km² in the ESA regions and provide an economic basis for state-specific conservation strategies to support national climate targets.