In the race to contain the climate emergency, governments worldwide are scrambling to cut carbon emissions. From encouraging people to walk instead of drive, to planting millions of trees, the aim is to limit global warming to 1.5°C. But some are planning to put them - yes, the actual CO2 emissions - into the ground, using a form of technology called Carbon Capture and Storage (CCS). This allows us to trap up to 90 per cent of the CO2 that would normally enter the atmosphere, under our feet. How does it work? Capturing carbon and storing it is a complicated process, but promises massive pay-offs in the long run. So what does the process involve?