The Unassuming Economist

From a paper by Galina Hale, Michael Halling, Nora Alice. Paulus, and Han H.G. Pham:

“Limiting global warming to 1.5 degrees requires that cumulative carbon dioxide emissions remain
within a finite remaining carbon budget. How this budget is allocated across countries raises
questions of fairness and development. This paper evaluates whether equity-based carbon
allocations are compatible with sustained economic growth in emerging and developing economies.
We compute country-level fair shares of the remaining carbon budget under the equal-cumulativeper-
capita (ECPC) principle. Using data for 162 countries between 1950 and 2023, we then estimate
the historical relationship between income and per-capita CO2 emissions across income groups and
use these elasticities to simulate cumulative emissions until 2050. Our results show that ECPC
implies strongly negative remaining carbon budgets for most advanced economies, while lowerincome
countries retain positive but constrained allocations. Under historically observed income–
emissions elasticities, many developing countries would exceed their fair shares when converging
toward advanced-economy income levels. At the aggregate level, unused allocations offset only
17% of the combined carbon budget shortfall implied by countries exceeding their allocation and
the negative fair shares arising from historical responsibilities. In a scenario in which we assume
that the technology of advanced economies is transferred to all countries, the carbon budget
coverage increases to 38%.”