From brain drain to geopolitical talent competition: scientific diasporas and the future of Global South development.

Scientific diasporas have emerged as increasingly important actors in global science, technology, and innovation (STI) ecosystems. In the context of geopolitical fragmentation, technological competition, and intensifying global inequalities, talent mobility is no longer solely a migration issue but a strategic dimension of development, science diplomacy, and international influence. This policy review argues that Global South countries should move beyond traditional "brain drain" narratives and instead adopt long-term strategies that view scientific diasporas as transnational development partners and components of broader "networks of networks." Drawing on literature related to scientific diasporas, global talent competition, science diplomacy, and migration studies, this review analyzes how scientific diasporas contribute to development through knowledge transfer, institutional partnerships, capacity building, innovation ecosystems, and policy engagement. It also examines the implications of recent geopolitical shifts, including the growing global competition for talent, technological nationalism, changes in U.S. science and immigration environments, Europe's strategic talent policies, and the rise of emerging scientific hubs beyond the West. Particular attention is given to the Global South, South-South cooperation, reverse brain drain, and the importance of equitable and inclusive knowledge systems. The paper concludes with policy recommendations aimed at strengthening science, technology, and innovation ecosystems and integrating scientific diasporas into national and international development strategies.