Green Fiscal Multiplier: Growth vs Emissions Decoupling Simulator

This simulator models a stylised economy where public fiscal stimulus is split between green capital (renewables, retrofits, transit infrastructure) and brown capital (legacy fossil energy and extraction), each accumulating and depreciating as its own stock. A Keynesian fiscal multiplier — set by how much of every respent dollar leaks out through saving, taxation, or imports — turns that injection into GDP growth, while a decoupling elasticity determines how much a greener capital mix reduces the emissions generated per dollar of output. A live 3D city of instanced sector towers grows, shrinks, and shifts colour in real time as green and brown capital stocks evolve, alongside numeric readouts for GDP, the active multiplier, emissions relative to baseline, and cumulative green vs brown jobs created.