A pasture open to all herders. Each one gains by adding another animal. The cost of overgrazing is shared by everyone. So each herder adds more animals, and the pasture is ruined. That scenario, described by Garrett Hardin in a 1968 essay, is the tragedy of the commons. It explains why shared resources get depleted even when everyone knows the outcome is bad.

The logic is compelling, but Hardin overstated the inevitability. Elinor Ostrom spent decades studying communities that manage shared resources successfully. Swiss farmers govern alpine pastures with rules that date back centuries. Spanish irrigation districts allocate water among farmers through elected tribunals. Japanese villages set fishing quotas. These systems work because they combine clear rules, monitoring, and graduated sanctions.

The tragedy is real when no governance exists. International waters, the atmosphere, and outer space are all vulnerable. The solution is not always privatization or government control. Sometimes it is community management, tailored to local conditions. Ostrom won a Nobel Prize for showing that communities can solve collective action problems without either markets or states. That insight has reshaped how economists and policymakers think about resource management.

Commons examples

• Ocean fisheries
• Atmospheric carbon
• Groundwater aquifers
• Public grazing land
• Antarctic krill stocks