The G-20 nations, that are industrializing at the fastest rate in the world, are dealing with serious environmental issues, particularly those pertaining to marine habitats. Because economic activity is affecting these environmental and marine ecosystems drastically, it is necessary to probe the factors that can promote sustainable development in developed and developing nations. Thus, understanding the possible effects of financial globalization (FG), green finance (GFN), and economic expansion on marine health is paramount. The study uses advanced methodologies to examine potential intersections between economic growth (GDP) and FG on the marine ecosystem of the G-20 countries between 2000 and 2022 in the context of fishing grounds load capability Curve (FGLCC) framework by showing a nonlinear relationship between marine conditions and income levels. Human capital is exerting positive impacts of (5.640–6.743 %) but FG is impacting (-4.182 to −5.490) on FGLCC. Furthermore, the work emphasizes the necessity of policies that strike a balance between the G-20's marine environmental sustainability and economic development, stressing the significance of deliberate legislative and strategic interventions. It is necessary to enact laws that favor sustainable fishing methods rather than focusing solely on boosting GDP through intensive fishing. Possible actions may involve allocating resources towards research and development in efficient fishing techniques, advocating for the adoption of environmentally friendly fishing equipment, and helping for the adoption of technologies that minimize unintended catch and damage to habitats. These discoveries have important ramifications for marine policymakers as they tackle marine environmental issues in the face of economic development. They are essential for improving marine requirements and safeguarding the health and well-being of future generations.