A short and succinct explanation of the Environmental Tracking concept: a system which, if adopted at scale, will bring about a seismic shift in our ability to harness the power of the investment system to place us on a more sustainable trajectory. This mechanism offers a framework by which we can create a financial incentive to reduce emissions within the global economy via the 'trojan horse' of the index model. It is a means by which the 'externality' of climate change can finally be 'internalised', decisively changing corporate behaviour throughout the world.. By influencing a company at the share price level, Environmental Tracking seeks to provide the platform for a smooth transition to a low carbon economy parallel to, and independent of, government action.