Unravelling the Interannual Changes in the Decade Observations of GHGs as Climate Indicators

Greenhouse gases emitted mainly by anthropogenic activities alter Earth’s energy balance and thus its climate. Here, we report the interannual variations of CO 2 and CH 4 for a decade between the years 2013 and 2022 over the suburban city of Shadnagar, near Hyderabad, India. CO 2 and CH 4 measurements have been carried out uninterruptedly under Indian Space Research Organisation (ISRO)–Geosphere–Biosphere Programme (ISRO-GBP) at the National Remote Sensing Centre (NRSC) laboratory and were calibrated periodically against the National Oceanic and Atmospheric Administration (NOAA) reference spans while meeting the World Meteorological Organization standards. Our observations indicate an annual atmospheric CO 2 and CH 4 growth rate over the area as 2.63 ppm year −1 and 17 ppb year −1 , respectively, during the 2013–2022 period. A stats model algorithm was applied to the long-term CO 2 and CH 4 observations to extract the interannual trend, seasonal, and residual components. The regulated activities of the terrestrial biosphere and El Niño–Southern Oscillation (ENSO) are connected to the interannual variability in CO 2 growth rates. A sudden spike in the annual growth of CO 2 concentration by 5.5 ppm year −1 in 2017 is attributed to the extended phase of El Niño in 2015–2016. The present study depicted the association of vegetative indexes with the variability of CO 2 and CH 4 concentrations at the site. Our study has shown that atmospheric CO 2 fluctuation is mainly associated with photosynthesis and biogenic respiration besides local and long-range anthropogenic forcing.