Assessing the impacts of vegetation cover loss on surface temperature, urban heat island and carbon emission in Penang city, Malaysia

Abstract

Rapid urbanization, human demands with dynamic hydrology, and land resources impact the carbon cycle and ecosystem resilience at the city level. The expansion of urban areas is continuously replacing the vegetative cover (VC), which accelerates carbon emissions (CE), raises land surface temperature (LST), and contributes to global warming. This study aimed to assess the CE dynamics in Penang City, Malaysia, resulting from land use and land cover (LULC) changes during 1996–2021 and to identify the impacts of CE dynamics on LST change and urban heat island (UHI) effects. In this regard, remote sensing and geospatial methods were applied to monitor the LULC changes and used the biomass carbon stock assessment techniques to quantify carbon storage. The findings of the study illustrate a 17% decrease in forest cover and an excessive increase in urban areas (22%), average LST (8 °C) and UHI (38%) in the last 25 years. The carbon stock (CS) concentration reveals a 24% decrease in high CS areas with more than 1% yearly decline from 1996 to 2021. In addition, due to the massive VC loss, carbon attracted the sun rays, which led to lower CS in built-up and no VC areas. The strong positive correlations between CE and LST and CE and UHI (R2 > 0.7961) at a significant level (p-value < 0.001) suggest that CE is highly responsible for the LST increase and UHI effects. This study proposes effective strategies, including afforestation, reforestation and urban greening practices through rooftop gardening, which can significantly improve the CS capacity and reduce climate change and global warming impacts in the fastest-growing cities.