Above-ground carbon dynamics in different arid urban green spaces

Urban areas are proven sources of anthropogenic carbon dioxide (CO₂) emissions, but urban greenery offers an opportunity to mitigate climate change impacts. Satellite remote sensing is valuable tool in assessing current and historical carbon stock dynamics. In this study, we estimated above-ground carbon (AGC) stock within four land use types including parks and gardens, avenue plantations, open greenery and institutional greenery in selected locations in Muscat Governorate through field measurement and satellite applications. Five different estimated spectral vegetative indices (VIs) acquired from Landsat 8 OLI were employed to develop linear and non-linear regression models between the spectral vegetative indices and the AGC stocks. The model with the highest coefficient of determination was used to estimate the AGC of the entire selected locations in Muscat Governorate for the year 2014 and 2017. The study results showed that both normalized differential vegetation index (NDVI) and ratio vegetative index correlate strongly with AGC in Parks and gardens with NDVI showing moderate correlation with AGC in Avenue plantations. The AGC in CO₂ equivalence in Muscat Governorate, Oman, for 2014 and 2017 were estimated to be 5987 and 9591 tons, respectively, with an annual sequestration rate of 1201 tons. The social value of the current CO₂ equivalent storage for 2017 was US $ 537,127.00 (OMR 206,802.85). Background turf grass and impervious surfaces might have affected the AGC–VIs correlations within the land use types. Urban greening projects involving plantation of high biomass trees may enhance urban carbon sequestrations.