Environmental Advances (Jul 2024)
Spatio-temporal variation of atmospheric CO2 and its association with anthropogenic, vegetation, and climate indices over the state of Bihar, India
Abstract
Carbon dioxide (CO2) in the Earth's atmosphere is a significant greenhouse gas and plays a pivotal role in shaping the carbon dynamics of specific regions. Here, we have examined the spatio-temporal variations of atmospheric CO2 in the Bihar region of India and provided critical information regarding climate change mitigation. NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite retrieved dry air column average atmospheric CO2 concentrations (XCO2) datasets (2015-2021) are used to analyse hot/cold spots, anomalies, hot/cold moments, and their relationships with Bihar's climate and vegetation indices. The highest CO2 concentration (416 ± 1.5 ppm, hot moments) is found in April and May (summer season) and the lowest concentration (406 ± 1.6 ppm, cold moments) is seen in monsoon season. The results reveal that seasonal variations of XCO2 are instrumental in comprehending Bihar's annual carbon dynamics, impacting factors such as plant growth and crop yields. Anomalies and hotspots analyses identify Kaimur, Munger, and Paschim Champaran as significant hotspots, which are house of major industries, power stations, cement factories and mining sites. Moreover, the study shows significant negative correlations (p < 0.001) between XCO2 and various parameters, including Sun Induced Chlorophyll Fluorescence (SIF) at wavelengths 740 and 757, Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and relative humidity. Particularly, NDVI and EVI changes explain XCO2 variability by 26 % (p < 0.001) and 24 % (p < 0.001), respectively. Additionally, relative humidity accounted for 37 % (p < 0.001) of the variance in XCO2. Our results indicate that the socio-economic condition of the study area has not been changed significantly during the study period. Further, the increase in afforestation activities has counterbalanced the small increase in CO2 due to developmental process over limited locations. These findings contribute significantly to our understanding of regional carbon dynamics of Bihar and their implications for climate change mitigation efforts.
