The document discusses the unsustainability of modern cities and proposes a new urban design model called "urban eco-regions". It argues that cities are overly dependent on resources from outside their boundaries and produce too much waste. It suggests redesigning cities to be more self-sufficient by including their surrounding productive lands and ecosystems within their political jurisdictions. The goal would be for urban eco-regions to meet most of their residents' needs locally while dramatically reducing their ecological footprints to become contributors rather than burdens to the global environment.