Contents lists available at ScienceDirect Atmospheric Environment journal homepage: www.elsevier.com/locate/atmosenv Carbon sequestration by mangrove forest: One approach for managing carbon dioxide emission from coal-based power plant Raghab Ray * , Tapan Kumar Jana Department of Marine Science, University of Calcutta, 35 B. C. Road, Kolkata, 700019, India ARTICLE INFO Keywords: Carbon dioxide Thermal power plant Mangrove Sundarban ABSTRACT Mangroves are known as natural carbon sinks, taking CO 2 out of the atmosphere and store it in their biomass for many years. This study aimed to investigate the capacity of world's largest mangrove, the Sundarbans (Indian part) to sequester anthropogenic CO 2 emitted from the proximate coal-based thermal power plant in Kolaghat (∼100 km away from mangrove site). Study also includes Kolkata, one of the largest metropolises of India (∼150 km away from mangrove site) for comparing micrometeorological parameters, biosphere-atmosphere CO 2 exchange fluxes and atmospheric pollutants between three distinct environments: mangrove-power plant- metropolis. Hourly sampling of atmospheric CO 2 in all three sites (late December 2011 and early January 2012) revealed that CO 2 concentrations and emission fluxes were maximum around the power plant (360–621 ppmv, 5.6–56.7 mg m -2 s -1 respectively) followed by the metropolis (383–459 ppmv, 3.8–20.4 mg m -2 s -1 respec- tively) and mangroves (277–408 ppmv, -8.9–11.4 mg m -2 s -1 , respectively). Monthly coal consumption rates (41–57, in 10 4 ton month -1 ) were converted to CO 2 suggesting that 2.83 Tg C was added to the atmosphere in 2011 for the generation of 7469732 MW energy from the power plant. Indian Sundarbans (4264 km 2 ) se- questered total of 2.79 Tg C which was 0.64% of the annual fossil fuel emission from India in the same time period. Based on these data from 2010 to 2011, it is calculated that about 4328 km 2 mangrove forest coverage is needed to sequester all CO 2 emitted from the Kolaghat power plant. 1. Introduction As per IPCC AR5 (2014), in the past decade of 2000–2010, an- thropogenic emissions of green house gases (GHGs) increased at a rate of 2.2% per year and reached up to 49 ± 4.5 Pg CO 2 -equivalent per year in 2010 (1 Pg = 10 15 g). Same report revealed that emissions of carbon dioxide (CO 2 ) from fossil fuel combustion and industrial pro- cesses contributed about 78% of that total GHGs emissions increase. Emissions of CO 2 from thermal power plants and cement industry are matter of concern because of their growing magnitude, the resulting increase in atmospheric concentrations of CO 2 , the concomitant changes in climate, and the direct impact of increased atmospheric CO 2 on ecosystems and energy demand (Andres et al., 2012; Ciais et al., 2013). In 2012, fossil fuel combustion as well as cement industry contribute 9.7 ± 0.5 Pg C annually to the atmosphere which is 58% over 1990 (Le Quere et al., 2013; Peters et al., 2013). Reports also state that coal from thermal power industry shares the highest percentages (43%) towards global CO 2 emission while oil, gas and cement con- tribute the rest (Global Carbon Project, 2008). Despite decades of significant global warming, humanity is only now beginning sig- nificantly to address the reduction of CO 2 emissions caused by power generation and transport (IPCC, 2007). Hence, the reduction of CO 2 emissions must be humanity's paramount concern, and any cost-effec- tive zero-carbon technology is preferable to a carbon emitting one. Strategy-makers have been developing many roadmaps to reach the carbon neutrality especially pertaining to the thermal power emission by undertaking different carbon offset projects. Biosequestration, the uptake of anthropogenic CO 2 by vegetation is one of such approaches. Tropical forests processes about six times as much carbon as the anthropogenic emission. Changes in carbon dynamics in tropical forest with 50% contribution to global terrestrial gross primary production (GPP) (Grace et al., 2001) could alter the pace of climate change (Adams and Piovesan, 2005). Storing carbon as standing forests or from harvested wood has long been recognized as an atmospheric CO 2 mi- tigation option (also known as ‘green carbon’). As for example, Schroeder (1992) estimated that 15–36 Pg C could be stored in tropical plantations and 50–100 Pg C sequestrated on a global scale (Winjum et al., 1992). A calculation by Lehmann (2007) indicates that an http://dx.doi.org/10.1016/j.atmosenv.2017.10.019 Received 2 March 2017; Received in revised form 4 October 2017; Accepted 7 October 2017 * Corresponding author. Current affiliation: Laboratoire des Sciences De l’Environnement Marin (LEMAR), UMR 6538, (UBO/CNRS/IRD/IFREMER), IUEM, rue Dumont d’Urville, 29280, Plouzané, France. E-mail addresses: raghab.ray@gmail.com, raghab.ray@univ-brest.fr (R. Ray). Atmospheric Environment 171 (2017) 149–154 Available online 12 October 2017 1352-2310/ © 2017 Elsevier Ltd. All rights reserved. MARK