Atmospheric CO₂ source and sink patterns over the Indian region

Abstract. In this paper we examine CO₂ emission hot spots and sink regions over India as identified from global model simulations during the period 2000–2009. CO₂ emission hot spots overlap with locations of densely clustered thermal power plants, coal mines and other industrial and urban centres; CO₂ sink regions coincide with the locations of dense forest. Fossil fuel CO₂ emissions are compared with two bottom-up inventories: the Regional Emission inventories in ASia (REAS v1.11; 2000–2009) and the Emission Database for Global Atmospheric Research (EDGAR v4.2) (2000–2009). Estimated fossil fuel emissions over the hot spot region are  ∼  500–950 gC m⁻² yr⁻¹ as obtained from the global model simulation, EDGAR v4.2 and REAS v1.11 emission inventory. Simulated total fluxes show increasing trends, from 1.39 ± 1.01 % yr⁻¹ (19.8 ± 1.9 TgC yr⁻¹) to 6.7 ± 0.54 % yr⁻¹ (97 ± 12 TgC yr⁻¹) over the hot spot regions and decreasing trends of −0.95 ± 1.51 % yr⁻¹ (−1 ± 2 TgC yr⁻¹) to −5.7 ± 2.89 % yr⁻¹ (−2.3 ± 2 TgC yr⁻¹) over the sink regions. Model-simulated terrestrial ecosystem fluxes show decreasing trends (increasing CO₂ uptake) over the sink regions. Decreasing trends in terrestrial ecosystem fluxes imply that forest cover is increasing, which is consistent with India State of Forest Report (2009). Fossil fuel emissions show statistically significant increasing trends in all the data sets considered in this study. Estimated trend in simulated total fluxes over the Indian region is  ∼  4.72 ± 2.25 % yr⁻¹ (25.6 TgC yr⁻¹) which is slightly higher than global growth rate  ∼  3.1 % yr⁻¹ during 2000–2010.