The global mismatch between equitable carbon dioxide removal liability and capacity

Limiting climate change to 1.5℃ and achieving net-zero emissions would entail substantial carbon dioxide removal(CDR) from the atmosphere by the mid-century,but how much CDR is needed at country level over time is unclear.The purpose of this paper is to provide a detailed description of when and how much CDR is required at country level in order to achieve 1.5℃ and how much CDR countries can carry out domestically.We allocate global CDR pathways among 170 countries according to 6 equity principles and assess these allocations with respect to countries’ biophysical and geophysical capacity to deploy CDR.Allocating global CDR to countries based on these principles suggests that CDR will,on average,represent～4% of nations’ total emissions in 2030,rising to ～17% in 2040.Moreover,equitable allocations of CDR,in many cases,exceed implied land and carbon storage capacities.We estimate～15 % of countries(25)would have insufficient land to contribute an equitable share of global CDR,and ～40% of countries(71)would have insufficient geological storage capacity.Unless more diverse CDR technologies are developed,the mismatch between CDR liabilities and land-based CDR capacities will lead to global demand for six GtCO2carbon credits from 2020 to 2050.This demonstrates an imperative demand for international carbon trading of CDR.