Urban Development Impacts on Ecosystem Services: Modeling and Valuation of Carbon Storage in the Tehran Metropolis

The rapid growth of urbanization in Iranian metropolises, especially Tehran, has caused significant changes in land use and cover, and consequently, a decrease in ecosystem services, including carbon storage. This study aimed to model and value changes in carbon storage in Tehran's ecological metabolism over three decades (1994–2024). Multi-temporal Landsat satellite images, advanced processing in Google Earth Engine, and the Random Forest algorithm were used for land use/cover classification. In addition, 66 urban soil samples were collected and analyzed to estimate soil organic carbon. The InVEST model was used to simulate changes in four main carbon pools (aboveground biomass, belowground biomass, soil, and dead organic matter). In addition, using economic valuation frameworks and global market reference rates, losses and benefits from carbon changes were calculated in the form of monetary indices. The results showed that over the study period, the area of ​​green spaces decreased from 14.19% in 1994 to 11.87% in 2024. These changes, along with the conversion of wasteland to construction, led to a significant reduction in carbon storage. Specifically, about 280,000 tonnes of carbon (equivalent to $7.62 million) were lost between 1994 and 2004, and more than 151,000 tonnes of carbon (equivalent to $4.11 million) between 2014 and 2024. Field-based models revealed several localized zones of carbon decline along with areas that could feasibly be restored. The results suggest that rapid urban growth and the steady loss of vegetation cover have greatly weakened the city’s capacity to retain carbon, and in turn, reduced its economic and ecological value. These observations highlight the importance of incorporating ecosystem service valuation into broader planning practices, ensuring that urban development does not undermine environmental integrity and contributes to climate resilience in large cities.