What are we missing? A systematic mapping of climate change projections in the Brahmaputra River Basin

The Brahmaputra River Basin (BRB) is an ecologically sensitive region, facing threats from anthropogenic interventions and climate change. Geopolitical tensions among the riparian nations have impeded collaboration, resulting in a gap in basin-wide research. Despite limited scientific understanding, especially regarding climate-related impacts, several water infrastructure projects, are planned on BRB. To bridge this gap, we explored the current understanding of future climate scenarios in BRB by systematically reviewing the scientific literature on climate change projections from 1985 to 2023. The findings reveal a steady increase in academic research since 2012, with most scientific literature concentrating on the Indian part of the basin (n = 21), followed by studies on China (n = 15), Bangladesh (n = 10) and Bhutan (n = 2). Only a few papers (n = 13) consider the entire BRB, indicating that most studies focus on specific river segments. We found a significant gap in research collaboration among BRB riparian countries, in addition to a lack of publications focusing on climate extreme events. Challenges due to limited observed data and restricted data sharing among the riparian nations were discussed. Our findings underscore the need for basin-wide collaborative research that addresses knowledge gaps and supports evidence-based policy-making in the BRB.