Z-factor of the climate crisis

The world faces twin problems of climate crisis and injustice. Countries in the global North have far exceeded their fair share in the global carbon budget, while countries in the South are well below their fair share. A simple solution would be for the North to absorb its excess emissions through net-negative emissions, which we call Z-factor. However, given the current technology, this is not possible. If the South bears the burden of adjustment by absorbing the excess emissions, it will perpetuate injustice. But if the South gets a right to burn its fair share, it would undermine the fight against the climate crisis. We argue that addressing these two issues is not mutually exclusive. If the North funds both the green path of declining emissions and the carbon removal process in the South while achieving decarbonization at the earliest, we can reach global net zero (GNZ) ahead of the current nationally determined commitments (NDCs). Nations that have exceeded their fair share will pay for their own and surplus nations’ (mostly in the South) decarbonization based on both current stock and prospective flows of overshoots. Deficit countries (in terms of carbon budget) cannot move into surplus, but high flows in the surplus camp may flip to the deficit side. After this flip, they too must start paying for their deficits, ensuring justice in a dynamic sense. There should be a base price for the accumulated Z-factor deficit nations pay, but it can be staggered over the decarbonization period. Future overshoot emissions should have a gradually increasing price to force decarbonization and limit the climate crisis. To make this work, we need an international carbon fund (ICF) to act as an arbiter and have the final say. Leaving this job to the markets is too risky.