Since the pre-industrial era (1990s), greenhouse gas (GHG) emissions from hydroelectric reservoirs have been a debatable subject of interest due to a substantial contribution to global warming. Rising demand for various renewable and nonrenewable energy resources became necessary for rapid economic growth to the exponentially rising population in developing countries. Reducing GHG emissions is the key target of COP-26 for climate change mitigation. However, precise methodologies for quanti cation of GHG, key parameters affecting emission rate is a challenging task attributed to limited tools, techniques for GHG measurement, uncertainty rate in measurement, insu cient GHG database, and huge spatiotemporal variability of emission in global reservoirs. This work highlights the present scenario of GHG emissions from renewable energy with targeted approach on hydroelectric reservoirs, methodological know-how, interrelation between parameters affecting GHG emission, and mitigation strategies. Apart from this, major tools and techniques to predict GHG emissions from hydroelectric reservoirs, accounting of GHG emissions, life cycle assessment, sources of uncertainty, and knowledge gaps have been discussed in detail.

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Land degradation is one of the most important factors responsible for the alarming situation of food security, human health, and socioeconomic development in the country. Currently, 120.7 M ha of land in the country is affected by land degradation, out of which 85.7 M ha of land is affected by soil erosion caused by water and wind. Moreover, physical, chemical, and biological degradation are the major forms of land degradation in the country. Deforestation or tree cover loss (2.07 M ha) from 2001 to 2021, intensive rainfall (>7.5 mm ha−1), uncontrolled grazing (5.65 M ha), indiscriminate use of fertilizers (32 MT year−1), and shifting cultivation (7.6 M ha) are other major factors that further aggravate the process of land degradation. In order to alleviate the problem of land degradation, numerous agroforestry technologies have been developed after years of research in different agroclimatic zones of the country. The major agroforestry systems observed in the country are agri-horticulture, silvipasture, and agri-silviculture. This review indicates the potential of agroforestry in enhancing carbon sequestration (1.80 Mg C ha−1 year−1 in the Western Himalayan region to 3.50 Mg C ha−1 year−1 in the island regions) and reduced soil loss and runoff by 94% and 78%, respectively, in Northeast India. This can be concluded that the adoption of the agroforestry system is imperative for the rehabilitation of degraded lands and also found to have enough potential to address the issues of food, environmental, and livelihood security. This review’s findings will benefit researchers, land managers, and decision-makers in understanding the role of agroforestry in combating land degradation to enhance ecosystem service in India and planning suitable policies for eradicating the problem effectively.