The formula: Each person on Earth would have an equal right to emit carbon, so countries would be allocated emissions targets strictly according to population. To exceed these targets, they would have to buy spare entitlements from poor nations and those that had invested in low-carbon technologies.
Advantages: Fairness, and no need for complex negotiations. Every country would have a target. Fixed emissions targets can be tied to scientific criteria for protecting the climate.
Disadvantages: Possible incentive for countries to increase their populations.
Winners: Poor nations like India, whose per-capita emissions are currently just 6 per cent of those…
