The gold column is the economy's capital stock — it grows from investment but needs both an available resource base and a tolerable pollution load to keep expanding. The orbiting nodes are the shared resource stock: each one dims and sinks as the stock is drawn down, and the haze around the scene thickens and reddens as ecological pressure (pollution, land and climate stress) builds up. The three stocks feed back on each other every tick.
dCapital/dt = growth · Capital · Resource · (1 − Pressure) − depreciation · Capital
dResource/dt = regen · (1 − Resource) − extraction · (1 − 0.8·innovation) · Capital
dPressure/dt = extraction · (1 − innovation) · Capital · k − decay · Pressure
- Growth drive — how aggressively capital is reinvested; higher values grow the economy faster but draw down resources and pressure faster too.
- Resource extraction — how resource-intensive the economy's output is per unit of capital.
- Green innovation — efficiency and clean technology; it cuts both the resource draw and the pollution generated per unit of growth without slowing growth itself.
- Ecological regeneration — how fast the resource base replenishes and pressure would ease on its own (forests regrow, soils recover, carbon sinks work) if given room.
Real-world relevance: an economy that grows only by extracting more and polluting more eventually strangles its own inputs — the resource stock collapses, pressure spikes, and growth reverses. Raising green innovation and regeneration relative to growth and extraction is what keeps the system in a sustainable steady state instead of a boom-bust collapse — the core argument for decoupling growth from resource throughput within planetary boundaries.