Atmospheric ¹⁴C Variability Recorded in Tree Rings from Peninsular India: Implications for Fossil Fuel CO₂ Emission and Atmospheric Transport

Radiocarbon analysis in annual rings of a teak tree ( Tectona grandis ) is reported in comparison with previously published results. Samples (disks) were collected from Hoshangabad (22°30′N, 78°E), Madhya Pradesh, in central India. The previously published sample was collected from Thane (19°12′N, 73°E), Maharashtra, near the west coast of India (Chakraborty et al. 1994). Two short Δ 14 C time series were reconstructed with these tree samples to capture the bomb peak of atmospheric 14 C and the spatial variability in this record. These time series represent the periods 1954–1977 and 1959–1980 for Hoshangabad and Thane, respectively. The 14 C peaks in these places appear around 1964–1965. The Hoshangabad tree records a peak Δ 14 C value of 708 ± 8%, which conforms to the peak value of Northern Hemisphere Zone 3 as described in Hua and Barbetti (2004). But the peak Δ 14 C at Thane is somewhat less (630 ± 8%) probably due to the dilution by fossil fuel CO 2 free of 14 C emanating from the neighboring industrial areas. This depletion of peak values has been used to estimate the local emission of fossil fuel CO 2 , which is approximately 2.3% of the background atmospheric CO 2 concentration.