appreciated, salinity ingression may increase due to the altered species combination, which could affect the water table and thus water sources. Women would be especially vulnerable since they spend a significant amount of time collecting fuelwood and drinking water.

# **6. Concluding Remarks**

Despite the widely‐acknowledged, treaty‐protected ecological status of the Sundarbans, concerns related to growing aquatic salinity have not yet been incorporated into regional management protocols. Over time, eastward meandering of the Ganges and Brahmaputra is reducing freshwater inflows significantly. Because the region is quite flat, strong tidal effects may travel long distances upstream, even at the current sea level. These effects will be exacerbated by continuing sea‐level rise. As long as such dynamics continue, efforts to improve local ecological conditions through changes in hydrological regime (e.g., river training and other engineering work) will likely be futile (Potkin 2004). Thus, it appears that engineering attempts to control rising salinity in the Sundarbans are unlikely to succeed.

The Indian Sundarbans is a UNESCO World Heritage Site. Effective conservation management will require establishment of location‐specific baseline data for tree stand structures, tree abundance, species richness and diversity, export of nutrients, hydrological patterns, rates of sedimentation, and relative sea‐level rise (McLeod and Salm 2006). Such baseline data will permit monitoring of changes in Sundarban mangrove systems over time. Since mangroves depend on fluxes of both daily tides and freshwater, management protocols should include both connectivity between mangrove systems and nearby river sources and maintenance of upland freshwater catchments. Areas should be identified that are likely to survive sea‐level rise in a changing climate. Tidal fluctuations, varying pH, and salinity should be monitored to support assisted regeneration and colonization of suitable mangrove species, where necessary. Attempts to restore mangrove areas that are currently degraded should also be undertaken.<sup>10</sup> Since changes in mangrove stocks induced by rising aquatic salinity are likely to change the prospects for forest‐based livelihoods, resources should also be directed to the development of alternative livelihoods for mangrove‐dependent households. Sea‐level rise will continue beyond 2100, even if greenhouse gas (GHG) emissions are stabilized in the near future.<sup>11</sup> The impacts on globally‐important mangrove ecosystems and the socioeconomic implications for vulnerable populations will undoubtedly be an important part of this story. High‐resolution

> 10 It is worth noting that local women’s groups can be engaged in nursery preparation of these salt‐tolerant species as part of community‐based mangrove restoration activities.

> 11 Current scientific estimates are that sea level may rise by 1 m or more in the 21st century (Hansen et al. 2011; Vermeer and Rahmstorf 2009; Pfeffer, Harper, and O’Neel 2008; Rahmstorf 2007; Dasgupta et al. 2009; Brecht et al. 2012). It is feared that sea level may even rise by 3 m or more by 2100, in light of new evidence on ice‐cliff instability of the Antarctic (https://www.nature.com/articles/nature17145; http://www.nature.com/news/antarctic‐model‐ raises‐prospect‐of‐unstoppable‐ice‐collapse‐1.19638; https://climatefeedback.org/evaluation/antarctica‐doomsday‐ glaciers‐could‐flood‐coastal‐cities‐grist‐eric‐holthaus/).

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