Carbon Cancellation project offers a new path to decarbonisation for the built environment

The City of London’s Carbon Cancellation Service (C4S) introduces a fundamentally new approach to decarbonising the built environment by leveraging compliance carbon markets rather than relying solely on traditional voluntary offsets.  Alderman Professor Michael Mainelli is a visiting professor at the Bartlett School of Sustainable Construction and was Lord Mayor of London 2023-2024.  His mayoral theme, “Connect To Prosper”, showcased London’s ability to address global problems with multi-disciplinary solutions.  Climate change is one such problem and Connect To Prosper contained a large sustainability initiative working towards better solutions integrating financial market tools.

C4S enables businesses and individuals to purchase and cancel regulated carbon emission allowances from systems like the UK Emissions Trading Scheme (ETS). Once purchased, these allowances are permanently removed from circulation, meaning major polluters can no longer use them to emit CO₂. This effectively “tightens the cap” on emissions, reducing the total amount of carbon that can be legally released. This model is distinct from, though compatible with, voluntary offsets, which typically fund projects that remove or avoid emissions elsewhere but do not directly reduce the official cap on emissions.

Why This Matters for the Built Environment:

• Urban areas are responsible for around 43% of global emissions, with the built environment (infrastructure, transport, materials) being a major contributor.
• Many emissions from construction and building operations are “residual”—difficult or impossible to eliminate entirely with current technology or practices.
• Carbon cancellation offers a credible, measurable, and transparent way for architects, urban planners, developers, and engineers to address these unavoidable emissions and meet net-zero commitments

The City of London Corporation, under its Climate Action Strategy, has already achieved significant emissions reductions and is on track to reach net zero in its operations by 2027.

C2Zero, the company behind C4S, has operated similar schemes in Australia and New Zealand and is now expanding in the UK with support from the City of London.