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Environmental degradation can be predicted and managed in a sustainable manner by the perodic analysis of the Land Use/Land Cover (LULC) change pattern, which not only helps to revitalize the environment but also helps to improve future land-use policies. With the Rohingya influx in 2017, the Kutupalong Mega Camp area in Bangladesh is at a severe risk of environmental degradation as the area is experiencing remarkable LULC change. The aim of this research is to illustrate the LULC change in the Kutupalong Mega Camp before and after the refugee influx, as well as its impact on the surrounding environment because of this change. The spatial and temporal variation of the LULC is analyzed from the classified multi-temporal Landsat images for years-2015, 2018, and 2021. The study reveals gradual decrease in forest cover of the area, which is replaced by the increasing human settlements. The study found an inverse relation between the refugee influx and the vegetation cover, where a positive relation to the bare land and settlement exists. The area experienced about ten times increase in human settlements during 2015–2021, which resulted deforestation of surrounding forest cover. Between 2015 to 2021, 74 % of forest cover of the studied area has been cleaned up for newer settlements, with an increase of wetland to meet the needs of increasing refugee population which has made the scenario worse. We also noticed an increase of Land Surface Temperature (LST) within a short period, where the average temperature increase rate is 0.06% during 2015–2018 and 0.01% during 2018–2021. The ecosystem, wild-habitat, and the thermal environment has been disturbed to a great extent due to this drastic change of forest cover mostly by the increasing anthropogenic activities in this area. The study represents the present scenario in comparison to its natural setting just a few years ago, and may serve as a guidance for the concerned authorities and international humanitarian organizations to develop a sustainable, comprehensive, and environment-friendly land management plan in order to protect the surrounding forest-ecology as well as the humanitarian works.

Particulate matter (PM2.5) is one of the major threats to public health, particularly Dhaka City in Bangladesh, frequently cited as one of the worst cities in the World in terms of air quality. This study examines the effects of six environmental (land surface temperature (LST), digital elevation model (DEM), water vapor concentration, wind speed, rainfall, and normalized difference vegetation index (NDVI)) and six economic factors (population density, road density, gross domestic product (GDP), poverty rate level, and percentage of low-income groups in rural and urban setting) on PM2.5 concentration in five industrial cities of Bangladesh using geographically weighted regression modelling (GWR) and machine learning (ML) tools. The mean annual rate of PM2.5 concentration increased by > 42% during 2002–2020 in all cities. Dhaka and Narayanganj districts were affected the most. Goodness-of-fit (R2) was 93% (environmental factors) and 73% (economic factors). Environmental factors: LST (100%) and water vapor concentration (100%) were correlated positively with PM2.5, while DEM (100%), rainfall (83%), NDVI (81%), and wind speed (84%) had a negative relationship at 95% confidence level. β-coefficients of DEM (p < 0.02), LST (p < 0.01), water vapor concentration (p < 0.01), NDVI (p < 0.02), and poverty rate (p < 0.01) were correlated negatively. Moreover, machine learning has extracted a good prediction of PM2.5, ranging the R2 between 0.79 and 0.86%. This study can be replicated in other cities by incorporating socio-economical, local geo-environmental, and meteorological with other air pollutants.

Cities are being restructured as a result of globalization, information flows, and changing economic processes. Global cities become command and control centers for subordinate production centers, resulting in the transformation of the mega-metropolitan system from monocentric to polycentric. The purpose of this paper is to analyze the urban transformation of the Dhaka region, Bangladesh. We estimated urban areas using remote sensing techniques and nighttime light data analysis. The urban areas were extracted from VIIRS nightlight datasets using ISODATA clustering algorithm. Urban areas were examined for two periods, from 2012 to 2017 and from 2017 to 2022. Apart from visual examination, the extracted urban areas were validated through the use of random sample points. Urban transformation was determined using hotspot analysis and the differentiation index for urban expansion. The finding is that Dhaka has continued to grow due to the continuous population growth and industrial centers’ proximity. Secondly, the majority of physical expansion of the Dhaka region occurs along major arterial highways and shows a functional intra-regional decentralization of industrial agglomeration.

Urban density not only represents the intensity of travel demand, but also serves as a useful tool for quantifying the elements that influence travel behavior and demand. In this study, Khulna City of Bangladesh has been selected as a case study to explore the impacts of urban density on travel behavior in a city of a developing country. The average characteristics of urban density, as well as their impacts on travel behavior and demand, have been studied using geospatial analysis techniques. Urban densities have been categorized into Single Density (Population Density, Employment Density, and Building Density) and Composite Density (Household to Work trip Density, Household to School trip Density and Household to Shop trip Density) based on characteristics of travel behavior and demand. Descriptive statistics have been used to explore the impacts of urban densities on the various trip characteristics such as trip production, trip distance, trip cost, trip time, and trip mode. Diversity of trips and overall trip attraction areas have been identified using the Shannon diversity index and other spatial analyses. Trip production, trip distance, trip time, trip cost, and mode choice all show a positive linear relationship with urban single-density, according to this study. The everyday activities of residents are closely related to urban composite densities, and trip production increase in tandem with composite densities. It has been concluded that different urban densities have significant impacts on travel demand and travel behavior.

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.

This study monitors the forest ecology in Himchari National Park, Teknaf Wildlife Sanctuary, and between the areas in Cox's Bazar district, Bangladesh. The area has a rich biodiversity, including globally endangered species such as Asian Elephants (Elephas maximus) and Boilam Trees (Anisoptera scaphula), which are threatened by anthropogenic development, newly refugees’ unplanned settlements and their use of domestic energy. Geographic Information System (GIS) and Landsat satellite images are used to monitor forest coverage for 1995–2018. The Normalized Difference Vegetation Index (NDVI) is applied to quantify forest area. Focus group discussions and questionnaire surveys were conducted to reveal stakeholder perceptions about their dependency on forest resources as ecosystem services. Close to the refugee camp areas, the forest coverage changes to grassland due to the unsustainable forest resource extraction. Despite the free of charge supply of Liquefied Petroleum Gas, the refugees burn 2,380 metric tons of firewood every month to satisfy energy for cooking. Besides, 200,000 households frequently use bamboo, small trees, and shrubs to maintain their dwellings' structure. Thus, deforestation caused by immigration between 2017–2018 is similar to that caused by the effect of climate change, including severe tropical cyclones in 1994–1995. This research identifies domestic energy supply deficiency and impacts, and the need for comparatively durable housing materials to reduce stress on forest resources and health hazards.