Sharing global CO2 emission reductions among one billion high emitters

Shoibal Chakravarty, Ananth Chikkatur, Heleen De Coninck, Stephen Pacala, Robert Socolow, Massimo Tavoni

Research output: Contribution to journalArticleAcademicpeer-review

269 Citations (Scopus)


We present a framework for allocating a global carbon reduction target among nations, in which the concept of "common but differentiated responsibilities" refers to the emissions of individuals instead of nations. We use the income distribution of a country to estimate how its fossil fuel CO2 emissions are distributed among its citizens, from which we build up a global CO2 distribution. We then propose a simple rule to derive a universal cap on global individual emissions and find corresponding limits on national aggregate emissions from this cap. All of the world's high CO2-emitting individuals are treated the same, regardless of where they live. Any future global emission goal (target and time frame) can be converted into national reduction targets, which are determined by "Business as Usual" projections of national carbon emissions and in-country income distributions. For example, reducing projected global emissions in 2030 by 13 GtCO2 would require the engagement of 1.13 billion high emitters, roughly equally distributed in 4 regions: the U.S., the OECD minus the U.S., China, and the non-OECD minus China. We also modify our methodology to place a floor on emissions of the world's lowest CO2 emitters and demonstrate that climate mitigation and alleviation of extreme poverty are largely decoupled.

Original languageEnglish
Pages (from-to)11884-11888
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America (PNAS)
Issue number29
Publication statusPublished - 21 Jul 2009
Externally publishedYes


  • Climate change
  • Climate equity
  • Climate policy
  • Individual emissions
  • Inequality


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