4-OCEANS aims to assess the importance of marine life for human societies during the last two millennia. We contend that the harvest of marine resources played a critical, but as yet underappreciated and poorly understood, role in global history. To bridge this gap in our understanding, the four PIs will form an interdisciplinary team combining expertise in marine environmental history, climate history, natural history, geography, historical ecology and zooarchaeology. We will examine when and where marine exploitation was of significance to human society; how selected major socio-economic, cultural, and environmental forces variously constrained and enabled marine exploitation; and identify the consequences of marine resource exploitation for societal development. Through these objectives we will discover how marine resources as novel wealth altered societies throughout history. How might marine wealth have enabled some societies to escape food shortages? How did it trigger long-term socio-economic impacts and ecological consequences? How were marine resources valued, consumed, and energetically transformed? Revealing this history will open a new window on human-nature dynamics of profound importance for understanding developmental trajectories of human societies. 4-OCEANS will transcend the binary distinctions of East and West, global-north and global-south, indigenous and colonial, resource exploitation and wildlife conservation, nature and culture. In doing so, 4-OCEANS will uncover and chart historical trajectories towards sustainable and unsustainable food security and resource extraction, identifying their complex underlying drivers.