The Supply Chain of CO2 Emissions
Steven J. Davis, Glen P. Peters and Ken Caldeira
About the Data

The analysis is based on fossil energy resources of coal, oil, natural gas, and secondary fuels traded among 57 industrial sectors and 112 countries in 2004 (Narayanan and Walmsley, 2009). We use the term "countries" to describe the spatial disaggregation of this data, though in some cases we intend collections of related countries. CO2 emissions produced in each country (production emissions) are calculated using country-, sector- and fuel-specific data of CO2 emissions per unit of energy. Using trade data, these emissions are traced back to the point of extraction, even if the extracted fuels were processed in and re-exported from an intermediate country (extraction emissions). The forward link from production emissions to where goods are consumed (consumption emissions) are based on a global multi-regional model that ties sector-level economic data with trade data (Davis and Caldeira, 2010).

The difference between production emissions and extraction emissions represents the net difference in emissions related to traded fuels, and therefore equals emissions from imported fuels less emissions from exported fuels. Emissions from burning of traded fuels are distinct from emissions embodied in traded goods, which are the emissions produced during manufacture of the goods. The net of emissions embodied in trade represents the difference between production emissions and consumption emissions. By combining emissions related to trade in fuels and goods, it is possible to examine the difference between extraction emissions and consumption emissions and follow the supply chain of emissions from where fuels are extracted to where dependent goods or services are ultimately consumed.

Trade Data

Data on international trade, economic input-output by sector, GDP, population, energy use and combustion-based CO2 emissions of each region-sector are all taken from Version 7.1 of the Global Trade Analysis Project (GTAP), which compiles the primary data from voluntary contributions of each region and harmonizes them to remove conflicts and inconsistencies (Narayanan and Walmsley, 2009).


Details of the Multiregional Input-Output Model (MRIO) used to calculate consumption emissions and the accounting model we developed to assess extraction emissions are available in the PNAS paper and its Supplemental Information (Davis, Peters and Caldeira, 2011).

Definition of Regions

The following list defines the regions of aggregated countries used in our analysis and presentations of the data:

Rest of Oceania: American Samoa, Cook Islands, Fiji, French Polynesia, Guam, Kiribati, Marshall Islands, Federated States of Micronesisa, Nauru, New Caledonia, Norfolk Island, Northern Mariana Islands, Niue, Palau, Papua New Guinea, Samoa, Solomon Islands, Tokelau, Tonga, Tuvalu, Vanuatu, Wallis and Futuna

Rest of East Asia: Macau, Mongolia, Democratic People’s Republic of Korea

Rest of Southeast Asia: Brunei Darussalam, Timor Leste, Myanmar

Rest of South Asia: Afghanistan, Bhutan, Maldives

Rest of North America: Bermuda, Greenland, Saint Pierre and Miquelon

Rest of South America: Falkland Islands, French Guiana, Guyana, Suriname, Belize

Rest of Central America (Rest of C. America): El Salvador, Honduras

Caribbean: Antigua and Barbuda, Bahamas, Barbados, Dominica, Dominican Republic, Grenada, Haiti, Jamaica, Puerto Rico, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Trinidad and Tobago, US Virgin Islands, British Virgin Islands, Anguilla, Aruba, Cayman Islands, Cuba, Guadeloupe, Martinique, Montserrat, Netherlands Antilles

Rest of The European Free Trade Association: Iceland, Liechtenstein

Rest of Eastern Europe: Republic of Moldova

Rest of Europe: Andorra, Bosnia and Herzegovina, Faroe Islands, Gibraltar, the former Yugoslav republics of Macedonia, Monaco, San Marino, and Serbia and Montenegro

Rest of former Soviet Union (Rest of FSS): Tajikistan, Turkmenistan, Uzbekistan

Rest of West Asia (Middle East): Bahrain, Iraq, Israel, Jordan, Kuwait, Lebanon, Occupied Palestinian Territory, Oman, Qatar, Saudi Arabia, Syrian Arab Republic, United Arab Emirates, Yemen

Rest of North Africa: Algeria, Libyan Arab Jamahiriya

Rest of West Africa: Benin, Burkina Faso, Cote d’Ivoire, Cape Verde, Ghana, Guinea, Guinea-Bissau, Gambia, Liberia, Mali, Mauritania, Niger, Saint Helena, Sierra Leone, Togo

Rest of Central Africa: Central African Republic, Cameroon, Congo, Gabon, Equitorial Guinea, Sao Tomo and Principe, Chad

Rest of South Central Africa (Rest of SC Africa): Angola, the Democratic Republic of the Congo

Rest of Eastern Africa: Burundi, Comoros, Djibouti, Eritrea, Kenya, Mayotte, Reunion, Rwanda, Somalia, Sudan, Seychelles

Rest of South African Customs Union: Lesotho, Namibia, Swaziland