Achieving ‘net zero’ greenhouse gas (GHG) emissions by 2050 is a target set in the Climate Change Act, with the UK Government pursuing even more stringent and specific intermediate targets from 2030. The term ‘net’ arose to address sectors with emissions deemed too difficult to become emission-free, by 2050, otherwise the overall emissions reduction target and endeavour might be undermined. The Sixth Carbon Budget, revealed in December 2020, reflects this target.