How do we Save the Earth? Parliament, People's Assemblies or Union Power?

As Bristolians what action should we be taking to stop global climate collapse? Should we focus our energies into supporting parliamentary parties and drive change through them, organise direct actions, campaign for People’s Assemblies, or look to bring about demands for change through unions? What are the strategic strengths and weaknesses of these approaches – where do they dovetail and where do they conflict?