The tragedy of the commons describes what happens when individuals overuse a shared resource. Each person gains from using more. The cost of depletion is spread across everyone. The result is a resource that is ruined for all. Garrett Hardin popularized the term in a 1968 essay, though the idea is older.

The classic example is a pasture open to all herders. Each herder benefits from adding one more animal. The grass is depleted by the combined grazing. Eventually the pasture is destroyed, and every herder loses. The same logic applies to fisheries, groundwater, and the atmosphere.

Elinor Ostrom challenged the inevitability of the tragedy. She documented communities that managed shared resources successfully for centuries through clear rules, monitoring, and sanctions. Her work earned a Nobel Prize. The lesson is that governance, not just privatization or regulation, can solve the problem.

Common examples

• Overfishing
• Groundwater depletion
• Air pollution
• Traffic congestion
• Public grazing land