"Hidden" CO2 Emissions in the Life Cycle of Electronics Imports

The "life cycle" environmental impacts of various products have been the subject of intense study, from the "cradle" of raw materials to the "grave" of recycling or refuse. As trade increases globally, international differences in economic efficiency, production methods, environmental legislation, and energy sources can lead to different environmental impacts of goods, depending on their location of production or disposal. International trade also requires transport between countries, which has associated impacts, and is an often overlooked aspect of globalization.

One of the most studied environmental impacts recently has been carbon dioxide (CO₂), the leading cause of global climate change. CO₂ emissions from internationally traded goods can be thought of in two ways: from a producer or consumer perspective. The producer perspective claims that responsibility for the emissions in the supply chain of exported goods should be given to the producer, while the consumer perspective claims the opposite — the responsibility rests with the consumer.

CO₂ from air transportation is often overlooked.

Since the Kyoto Protocol on climate change, there has been much discussion about which is the more appropriate accounting framework, though the producer perspective is the one currently held by the United Nations Framework Convention on Climate Change (UNFCCC). Several studies have estimated economy-wide "trade balances" of CO₂ emissions for countries in order to inform this debate. Essentially these "balances" reflect the difference between the CO₂ caused by the goods an economy produces and the CO₂ caused by the goods an economy consumes. For example, since China exports more than it imports, it probably has a net positive "trade balance" of CO₂, while the US it the opposite.

Electronics provide a relevant case study for such issues for several reasons:

1. Consumption of electronics has grown faster than nearly any other commodity group over the past decade, both for personal (household) consumption as well as for business and infrastructure building.
2. Electronics are one of the most heavily-traded commodity groups in the world.
3. Electronic components are very energy-intensive, requiring high-purity materials and substantial energy input.
4. Electronics are disproportionately shipped internationally by air, making international transport a potentially important part of the supply chain.

This article provides an overview of the growth in electronics consumption in the US during 1997, 2002, and 2004 and the global environmental implications from the production, transport, and sales of these goods. A key focus is on the CO₂ contribution of transportation on the overall life cycle of electronics and computer imports to the US.

METHODS AND PREVIOUS WORK

The main method used here is called multi-regional input-output analysis (MRIO), a generalized version of input-output analysis (IOA) which allows trade between several countries. Basically, IOA and MRIO use national-level economic data on supply chains, coupled with environmental data, to delineate the environmental impacts of producing different goods and services, from the cradle (raw materials) to the factory gate (production of the good, but not delivery or wholesaling/retailing).

In a previous study, Embodied Emissions in U.S. International Trade: Growth, Structure, and Uncertainties, 1997-2004, I produced a uni-directional trade model of the United States and its seven top trading partners: Canada, China, Mexico, Japan, Korea, the UK, and Germany. This work analyzed the total "embodied emissions" in US international trade (emissions occurring outside the US to make goods imported to the US) and its growth between 1997 (the base year for the latest US input-output model) and 2004.

Figure 1: Estimated embodied CO₂ emissions in imports to the US, 1997, 2002, and 2004

Methodological and data limitations make exact numbers for the total embodied emissions in imports difficult, but the trend is clear: electrical equipment (light bulbs, fixtures, etc) and electronics (including computer equipment and components, audio and video equipment, communications equipment, and all electronic components) are a significant factor in the substantial overall growth in US imports and their associated energy use/CO₂ emissions.