Predicting the carbon cost of land-use change in Bangladesh’s Chittagong hill tracts

A new study warns that continuing forest loss and land-use change in Bangladesh’s Chittagong Hill Tracts could steadily reduce the region’s ability to store carbon, with measurable environmental and economic consequences by 2043.

The research, published in Carbon Research, analyzed three decades of satellite data and used predictive modeling to assess how land use and land cover changes have affected carbon storage and sequestration in the Chittagong Hill Tracts, one of Bangladesh’s most important forested and ecologically sensitive regions. The study found that deep forest cover has declined while built-up areas, agricultural land, and shrubs with scattered trees have expanded. As a result, total carbon storage is projected to fall from 75,674 Mg in 1993 to 70,221 Mg by 2043.

“The Chittagong Hill Tracts are not only a biodiversity-rich landscape, but also a vital natural carbon reservoir,” said corresponding author A. S. M. Maksud Kamal of the University of Dhaka. “Our results show that land-use decisions made today will shape the region’s carbon balance, climate resilience, and economic value for decades to come.”

The Chittagong Hill Tracts, located in southeastern Bangladesh, contain a large share of the country’s forest resources and support diverse communities, agriculture, and ecosystems. However, the region has faced growing pressure from population growth, infrastructure development, agricultural expansion, traditional shifting cultivation, hill cutting, tourism, and illegal logging. These pressures have contributed to the conversion of dense forest into farmland, settlements, and more fragmented vegetation.

To understand these changes, the research team used Landsat satellite images from 1993, 2003, 2013, and 2023 to classify eight land-use and land-cover types: rivers and khals, lakes and ponds, brackish water aquaculture, deep forest, agricultural land, shrubs with scattered trees, bare land, and built-up area. They then used the Land Change Modeler, Cellular Automata Markov Chain modeling, and a Multi-Layer Perceptron neural network to predict future land-cover patterns for 2033 and 2043. Carbon storage and sequestration were estimated using carbon density data from above-ground biomass, below-ground biomass, soil organic carbon, and dead organic matter.

The results reveal a clear warning signal. From 1993 to 2023, deep forest declined by 6.23%, while shrubs with scattered trees increased by 10.34% and built-up area increased by 1.10%. Model projections suggest that deep forest will continue to shrink, with further increases in built-up land, agricultural land, and scattered vegetation by 2043.

These land-cover shifts directly affect the carbon balance of the region. The study estimated total carbon storage at 75,674 Mg in 1993, 72,359 Mg in 2003, 72,586 Mg in 2013, 71,569 Mg in 2023, 70,718 Mg in 2033, and 70,221 Mg in 2043. Carbon sequestration was negative for most periods, except for a small gain of 227 Mg between 2003 and 2013, likely linked to stronger environmental protection efforts during that decade.

The economic implications are also significant. Using the social cost of carbon, the study found that the value of sequestered carbon ranged from a loss of 263,944 USD to a temporary gain of 18,074 USD. Future declines in sequestration could therefore translate into continued economic losses as well as ecological degradation.

The authors emphasize that the findings can help policymakers identify forest degradation hotspots, prioritize reforestation, strengthen forest conservation, and design sustainable land-management strategies. Protecting remaining deep forest and restoring degraded areas could help Bangladesh enhance carbon sequestration, reduce climate-related risks, and preserve the ecological value of the Chittagong Hill Tracts.

“Our study provides a practical evidence base for climate mitigation planning,” said Kamal. “Forest conservation and sustainable land management are not only environmental priorities, but also economic necessities.”

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Journal reference: Khandaker, M., Kamal, A.S.M.M., Hossain, M.J. et al. Land use transformation and carbon sequestration in the Chittagong Hill Tracts, Bangladesh: a spatiotemporal and predictive analysis with economic implications. Carbon Res. 5, 27 (2026).   

https://doi.org/10.1007/s44246-025-00251-3  

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About Carbon Research

The journal Carbon Research is an international multidisciplinary platform for communicating advances in fundamental and applied research on natural and engineered carbonaceous materials that are associated with ecological and environmental functions, energy generation, and global change. It is a fully Open Access (OA) journal and the Article Publishing Charges (APC) are waived until Dec 31, 2025. It is dedicated to serving as an innovative, efficient and professional platform for researchers in the field of carbon functions around the world to deliver findings from this rapidly expanding field of science. The journal is currently indexed by Scopus and Ei Compendex, and as of June 2025, the dynamic CiteScore value is 15.4.

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