Monitoring biodiversity and climate-induced environmental changes in refugee-affected regions is essential for comprehending ecological degradation and formulating sustainable management measures. The Rohingya settlement regions in southern coastal Bangladesh constitute one of the most ecologically vulnerable landscapes where accelerated land alteration, vegetation removal, and thermal irregularities have exacerbated since the onset of mass displacement in 2017. This study seeks to measure biodiversity loss and evaluate the impacts of climate change on geomorphosites through a multi-index remote sensing methodology. Satellite imagery from Landsat-8, Landsat-9, and Sentinel-2, spanning 2015 to 2025, was processed in ArcGIS to calculate NDVI, EVI, EHI, TDVI and LST values. Spatial and temporal analyses were conducted to delineate vegetation dynamics, ecosystem health, habitat degradation and fluctuations in surface temperature. Statistical analysis revealed a strong and significant negative correlation between NDVI and land surface temperature (LST) (r < −0.70, p < 0.01), indicating that vegetation loss has directly intensified surface warming across settlement zones. Similarly, the Ecological Health Index (EHI) exhibited a significant inverse relationship with LST (p < 0.05), confirming progressive ecosystem stress associated with land cover alteration. Linear regression analysis further demonstrated a consistent declining trend in NDVI and EHI with increasing LST, quantitatively establishing vegetation degradation as a primary driver of localized climate change impacts in the study area. This analysis indicates a significant deterioration in vegetative health and coverage, as evidenced by declining NDVI, EVI, EHI, and TDVI trend values, alongside an increase in LST within major settlement clusters. This suggests considerable vegetation depletion and biodiversity stress, while TDVI trends corroborate extensive soil and vegetation moisture loss. Land surface temperature (LST) rose markedly to between 2.5 and 3.5 degrees, indicating substantial warming attributable to deforestation and land cover alteration. These findings highlight the significant and enduring environmental effects of the settlement, offering essential data to inform sustainable rehabilitation programs, biodiversity conservation, and climate-resilient actions in this ecologically sensitive area.