Methane emissions only negligibly reduce the ecosystem service value of wetlands and rice paddies in the mature Ganges Delta

Pal, Swades; Debanshi, Sandipta

Methane emissions only negligibly reduce the ecosystem service value of wetlands and rice paddies in the mature Ganges Delta

2022

Pal, Swades | Debanshi, Sandipta

Wetland provides a wide range of ecosystem services with immense value. However, methane (CH₄) emissions adversely affect ecosystem services, and it requires fixation cost. The objective of the present study was to estimate CH₄ emissions and ecosystem services value (ESV) and how much the fixation cost of CH₄ reduces the ESV. Since rice cultivation is a very common practice here, the paddy fields were also incorporated in this study. CH₄ flux and satellite data were employed for estimating the emissions with the help of two-factor (temperature and water availability) model. Global coefficients of ecosystem service value (ESV) that is defined as the monetary valuation of materialistic and non-materialistic services were adapted for estimating the ecosystem service of the CH₄ emitting sources. Results show that during the boro season (pre-monsoon summer paddy cultivation season), average monthly emissions of paddy fields are equal to the wetlands which are 0.16 t/km². During amon season (monsoon paddy cultivation season), this emissions is 0.7 t/km² and 0.53 t/km², respectively, from wetlands and paddy fields. Both wetlands and paddy fields emit a greater amount of CH₄ during amon season than boro season. Behind this seasonal variation, water availability in terms of precipitation-evaporation ratio plays a more vital role than temperature. Total estimated ESV is 928.51 million US$, and CH₄ fixation cost is 6.64 million US$ which is only 0.71% to total ESV. So, considering such huge net ESV, emphasis on wetland conservation and restoration are necessary.

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