A synthesis of carbon in international trade

Abstract

Abstract. In a globalised world, the transfer of carbon between regions, either physically or embodied in production, represents a substantial fraction of global carbon emissions. The resulting emission transfers are important for balancing regional carbon budgets and for understanding the drivers of emissions. In this paper we synthesise current understanding in two parts: (1) CO 2 emissions embodied in goods and services that are produced in one country but consumed in others, and (2) carbon physically present in fossil fuels, petroleum-derived products, harvested wood products, crops, and livestock products. We describe the key differences between studies and provide a consistent set of estimates using the same definitions, modelling framework, and consistent data. We find the largest trade flows of carbon in international trade in 2004 were fossil fuels (2673 MtC, 37 % of global emissions), CO 2 embodied in traded goods and services (1661 MtC, 22 % of global emissions), crops (522 MtC, 31 % of total harvested crop carbon), petroleum-based products (183 MtC, 50 % of their total production), harvested wood products (149 MtC, 40 % of total roundwood extraction), and livestock products (28 MtC, 22 % of total livestock carbon). We find that for embodied CO 2 emissions, estimates from independent studies are robust, and that differences between individual studies are not a reflection of the uncertainty in consumption-based estimates, but rather these differences result from the use of different production-based emissions input data and different definitions for allocating emissions to international trade. After adjusting for these issues, results across independent studies converge to give less uncertainty than previously assumed. For physical carbon flows there are relatively few studies to be synthesised, but differences between existing studies are due to the method of allocating to international trade, with some studies using "apparent consumption" as opposed to "final consumption". While results across studies are sufficiently robust to be used in further applications, more research is needed to understand differences and to harmonise definitions for particular applications.

Global Carbon Budget 2015

“…Dietzenbacher et al, 2012;Inomata and Owen, 2014;Karstensen et al, 2015;Moran and Wood, 2014). For this reason we do not provide an uncertainty estimate for these emissions, but based on model comparisons and sensitivity analysis, they are unlikely to be larger than for the territorial emission estimates (Peters et al, 2012a). Uncertainty is expected to increase for more detailed results, and to decrease with aggregation (Peters et al, 2011b; e.g.…”

“…It is also possible to account for the carbon trade in fossil fuels (Davis et al, 2011), but we do not present those data here. Peters et al (2012a) additionally considered trade in biomass.…”

Impacts Embodied in Global Trade Flows

“…An important observation was made by Peters et al ( 2012 ) in a pioneering comparative study: differences in consumption-based, embodied CO 2 emissions from different models were mostly due to the use of different territorial emission data and different defi nitions for allocating emissions to international trade. When adjusting for these issues, results were robust and in reasonable agreement.…”

“…Some studies have begun comparing the results obtained from different models, fi nding reasonable agreement as well as signifi cant discrepancies for certain indictors (e.g. Peters et al 2012 for CO 2 emissions and Schoer et al 2013 for raw materials).…”

The Diminishing Returns to the 2010 Human Development Index: Implications for Climate Policy and Sustainable Development

“…To adjust territorial data for trade, emissions that occur in the supply chain of consumer goods and services are allocated to the appropriate nation based on environmentally extended input-output analysis (see methods section of Peters et al, 2011). Studies suggest that uncertainty is higher for consumption-based emissions compared with territorial emissions (Lenzen, Wood, & Wiedmann, 2010), however they also indicate that the trends and absolute values are consistent across data, methods, and independent studies (Peters, Davis, & Andrew, 2012;Wiedmann, Lenzen, Turner, & Barrett, 2007;Wiedmann, 2009). To remain consistent with the consumption-based emission data-set from Peters et al (2011), this paper distinguishes developed nations as the countries included in Annex B and the developing and/or underdeveloped nations are classified as the non-Annex B countries to the Kyoto Protocol.…”