The majority of the emissions are released in rapidly industrialising parts of the developing world, such as China and India.
The study, by scientists at the Carnegie Institute of Washington in California, highlights the unresolved issue of responsibility for carbon dioxide that is released to make products for foreign markets.
Under the Kyoto protocol, emission targets apply to the country where the gases are produced. But China has so far resisted binding emissions targets, as it does not accept responsibility for emissions associated with making goods that are exported to wealthy nations.
Previous studies, by the Centre for International Climate and Environmental Research last year and Oxford University in 2007, have found that the UK is “outsourcing” much of its carbon emissions for the manufacture of goods to China.
For this study, Steven Davis and Ken Caldeira used published data on international trade from 2004 to build up a picture of how goods moved between 113 countries or regions and 57 industrial sectors, including machinery, vehicles, chemicals and food. By allocating carbon emissions to products and sources, they calculated the net emissions linked to countries imports and exports.
“Instead of looking at carbon dioxide emissions only in terms of what is released inside our borders, we also looked at the amount of carbon dioxide released during the production of the things that we consume,” said Caldeira.
Over one-third of the carbon emissions linked to goods used in many European countries were actually released in developing countries, the study shows. Imports to Germany and France were responsible for 233m tonnes and 170m tonnes of carbon dioxide emissions abroad respectively. Switzerland “outsourced” more than half of its carbon dioxide emissions, according to the report in Proceedings of the National Academy of Sciences.
“Just like the electricity you use in your home, we found that products imported by the developed countries of western Europe, Japan and the US cause substantial emissions in other countries, especially China,” said Davis. Nearly one-quarter of China’s annual carbon dioxide emissions, some 1.4bn tonnes, come from the manufacture of products and services that are ultimately exported, the report adds.
Jan Minx, an expert in environmental economics at the Stockholm Environment Institute at the University of York, said the study’s system of attributing emissions – based on which country’s consumption causes emissions rather than the country where the emissions are released – can help identify when international agreements to cut greenhouse gas emissions are being undermined. Some countries, the UK included, are increasingly becoming service-based economies, but they still import goods from countries that rely heavily on fossil fuels and have no binding emissions targets. “It’s not intentional, but it can have a detrimental effect on international agreements,” Minx said.
Obliging countries to cut carbon emissions beyond their national borders is fraught with political and practical difficulties, but this should not stop import-related emissions being taken into consideration in negotiations to cut emissions, Minx said. “It’s most feasible for a country to reduce emissions on their own territory, but this kind of accounting system can provide extra information for policymakers,” he added.
Adopting such an accounting system for greenhouse gas emissions could be fairer to developing countries, such as China and India, which rely heavily on fossil fuels to manufacture products for wealthy foreigners, the researchers said.
“Apart from an opportunity to inform effective climate policy, consumption-based accounting of emissions provides grounding for ethical arguments that the most developed countries – as the primary beneficiaries of emissions and with greater ability to pay – should lead the global mitigation effort,” the authors write.