The Wrong Threat

Senegalese artisanal fisheries face two threats: climate change altering fish stocks, and overfishing depleting them. Policy discussions often frame climate change as the primary risk. An agent-based model integrating climate, fishing effort, and socio-economic data reveals which threat actually matters.

Climate change has only a slight impact on artisanal fishing — even under the most extreme climate scenario considered. The fishery’s trajectory is nearly identical across climate projections. What determines the outcome is fishing effort. At current levels, the fishery collapses with massive fisher migrations regardless of climate scenario. With reduced fishing effort, a sustainable equilibrium emerges: approximately 250,000 tons per year, matching historical 2000s catch records, stable across all climate futures.

The migration patterns in the model are diagnostic. When fish stocks decline, fishers migrate — first to other fishing grounds, then out of fishing entirely. The migrations are not caused by climate but by depletion. They precede collapse and could serve as early warning indicators if monitored.

The through-claim: the system is dominated by the fast variable, not the slow one. Climate change is a slow, diffuse perturbation. Overfishing is a fast, concentrated one. The fast variable reaches the threshold of collapse before the slow variable produces measurable effects. Policy focused on climate adaptation addresses the wrong timescale — the fishery will collapse from overfishing decades before climate change would have mattered. The same dynamic applies wherever a system faces both a gradual environmental shift and an immediate resource extraction pressure: the extraction almost always wins the race to the tipping point.