Climate change is accelerating and is already affecting the marine environment. Estimating the effects of climate change on the production of fish resources, and their dependent societies, is complex because of: difficulties of downscaling Global Climate Models (GCM) to scales of biological relevance; uncertainties over future net primary production and its transfer through the food chain; difficulties in separating the multiple stressors affecting fish production; and inadequate methodology to estimate human vulnerabilities to these changes. QUEST_Fish, a research project led from the UK, is addressing some of these challenges through an innovative, multi-disciplinary approach focused on estimating the added impacts that climate change is likely to cause, and the subsequent additional risks and vulnerabilities of these effects for human societies. The project uses coupled shelf seas biophysical ecosystem models forced by GCM forecasts to predict ecosystem functioning in past, present, and future time-slices. For each slice, and for 20 Large Marine Ecosystems, we estimate plankton production and use this to estimate size-based fish production through models based on macro-ecological theory. Ways of assessing vulnerability of fisheries to future climate change are developed, including the market consequences for fish-based global commodities. The results provide a new framework and new insights into the complex interactions between humans and nature.