A. A. ENUNEKU

Methane (CH₄), with warming potential 84 times greater than CO₂ over 20 years, requires urgent mitigation for climate stabilization. This study compared atmospheric methane patterns between Delta and Adamawa States, Nigeria, using 2022–2024 Sentinel-5P TROPOMI satellite data processed through Google Earth Engine. Applying strict quality controls (qa_value ≥ 0.75) and statistical analysis (Mann-Whitney U test, Getis-Ord Gi*), the research revealed distinct emission signatures. Delta State exhibited concentrated industrial emissions, with 96.73% of hotspots at petroleum infrastructure (oil facilities, gas flaring, pipelines). Concentrations increased 1.37% from 1,915.47 to 1,941.72 ppb, showing high spatial heterogeneity (σ = 14.82 ppb) and minimal climate sensitivity. Adamawa State showed diffuse biogenic emissions from livestock (38.84%), waste (17.52%), and wetlands (25.80%), with 0.81% concentration increase (1,925.82 to 1,941.45 ppb), lower variability (σ = 9.85 ppb), but strong climate dependence (ρ = +0.58, p < 0.001). Both states showed accelerating trends (Delta: +13.05%/year; Adamawa: +11.38%/year), contradicting Nigeria's 30% reduction pledge by 2030. Results demonstrate that industrial and agricultural sources require distinct strategies: leak detection and infrastructure modernization for petroleum operations versus improved livestock management and waste infrastructure for agricultural systems. This baseline enables future monitoring of mitigation effectiveness.

The rapid urbanization of the 21st century significantly alters local climates, manifesting in phenomena like the Urban Heat Island (UHI) effect and elevated concentrations of greenhouse gases (GHGs). The COVID-19 lockdown offered a rare natural experiment to evaluate the extent to which human activities influence urban thermal environments and atmospheric conditions. This study employed remote sensing and Geographic Information System (GIS) techniques to analyse the effects of the COVID-19 lockdown on Urban Heat Islands (UHIs), Land Surface Temperatures (LST), and Greenhouse Gases (GHGs) in Abuja, Nigeria. Landsat 8 satellite imagery was used to derive UHI and LST data, while Sentinel-5P provided atmospheric measurements for key GHGs including sulphur dioxide (SO2), aerosols, and ozone (O3). The analysis covered three temporal phases which are the pre-lockdown (2017–2018), lockdown (2019–2020), and post-lockdown (2021–2024) and data were processed using Google Earth Engine and ArcGIS environments to classify spatial variations and identify thermal patterns across the study area. The results revealed a significant decline in both UHI and LST intensity during the lockdown period, with mean UHI values dropping from 6.00°C in 2017– 2018 to 4.93°C in 2019–2020, before rising again to 6.72°C post-lockdown. LST followed a similar trend, decreasing from 6.96°C to 5.14°C during lockdown and increasing thereafter. A corresponding reduction was also observed in atmospheric pollutants, with sulphur dioxide, aerosols, and ozone concentrations all declining during the lockdown. Pearson correlation analysis showed a strong positive relationship between UHI and LST (r = 0.786–0.877), confirming their interdependence and direct link to anthropogenic activity. These findings underscore the dominant role of human activities in shaping urban climatic and atmospheric conditions. The temporary cooling and emission reduction during the lockdown illustrate the potential environmental benefits of reduced fossil fuel consumption and improved urban planning. The study highlights the critical importance of integrating green infrastructure, energy-efficient systems, and climate-responsive policies into Abuja’s urban development framework. It further demonstrates the value of remote sensing and GIS as essential tools for continuous environmental monitoring and policy formulation toward achieving Sustainable Development Goals 11 (Sustainable Cities and Communities) and 13 (Climate Action)

Major contributions to the pollution in the atmosphere are Nitrogen dioxide (NO2) and Sulphur dioxide (SO2) from cement factories as well as other industrial activities in Urban and Rural areas. The study area covers Ibese, Paplanto, Abeokuta, Ewekoro and other rural areas as they play host to either cement factories or congested urban. This research compared the amount of NO2 and SO2 released into the atmosphere at Ibese, Papalanto and Abeokuta. Sentinel 5P data for the study area was used to monitor these pollutants. Google earth engine editor was used to extract the pollutants over the study area. The duration considered was a 4-month interval within year 2019 to 2021 which was used to present 3 spatial maps per year resulting in a total of 9 maps for both pollutants. SO2 concentration ranged between-0.000161 to 0.0000782;-0.000206 to 0.000162; 0.000194 to 0.000228, for 2019, 2020 and 2021 respectively. NO2 concentration ranged between 0.0000459 to 0.0000846, 0.0000491 to 0.0000947, 0.0000565 to 0.000122 mol/m2 for 2019, 2020 and 2021 respectively. The spatial distribution for both pollutants were regrouped into 4 classes namely low, moderate, high and very high. Ibese fell once within the low class, seven times within the moderate class, five times each within the high and very high class respectively considering both the NO2 and SO2 maps. Papalanto fell twice within the low class, once within the moderate class, six times within the high class and eight times within the very high class. Abeokuta fell six times within the moderate class and twelve times within the high class. The most dominant zone is the moderate zone followed by the high zone for SO2 and NO2 between 2019 and 2021. The frequency of occurrence of Papalanto and Ibese within the peak zone of SO2 and NO2 was very high when compared to the frequency of occurrence of Abeokuta which never fell beyond the high zone of either pollutant. This was attributed to the cement factory working nonstop located within Papalanto and Ibese.