Sets an effective cap on total emissions
which would reduce every year

There is widespread agreement that it would be very serious if the average global temperature were to rise by more than 2 degrees Celsius above that in pre-industrial times. A rise of about 0.7 degrees has already happened and another 0.7 degrees is inevitable because of the lags in the system. This means that there is very little scope for further greenhouse gas emissions before the 2 degree temperature target is breached. Accelerating climate change, through the earlier engaging of primary and secondary feedbacks than expected, are likely to make action even more urgent.

With a Cap and Share approach, the tonnage of those gases, expressed in terms of their CO2 equivalent (tCO2e), would be estimated. This would be the overall cap, the maximum amount that humanity could release over the years before it had brought its emissions down to the level at which they were being safely absorbed by the world's carbon sinks.

This total tonnage would be used to calculate the percentage rate at which the Earth's annual emissions had to be reduced to ensure that the overall cap was not exceeded.

This would give a series of annual caps, and these could be adjusted downwards if it was found after several years that the original overall cap had been too generous.

These caps would then form the basis setting the tCO2e in each citizen's Production Authorisation Permit entitlement.