Aerosol influence on climate outsourced through international trade

Much of the influence that aerosols produced in East Asia have on the climate is driven by consumption in developed countries rather than in East Asia itself, reports a paper published online this week in Nature Geoscience. The study shows that international trade shifts the climate impacts of aerosol emissions - known as radiative forcing - from net consuming countries to net producing countries.

Unlike greenhouse gases, aerosols (such as sulfate or black carbon) emitted through industrial processes or fossil fuel combustion typically only remain in the atmosphere for a short time (days to weeks). As a result, their influence on climate is usually strongest in the region around the source of their emission. Previous studies have demonstrated the role that international trade has in redistributing greenhouse gases and other pollutant emissions and in altering regional air quality, but the effects on climate forcing due to aerosols is unclear.

Jintai Lin, Qiang Zhang, Yi Huang and colleagues estimate aerosol emissions related to the production and consumption of goods and services for 11 global regions and then compare the influence that the production-related aerosols and consumption-related aerosols have on the global climate and the climate of those regions. They find that, as East Asia is a large net exporter of emissions-intensive goods, radiative forcing due to the production of goods in the region is much stronger than the radiative forcing related to the consumption of goods. However, for net importing regions, such as western Europe, North America and Oceania OECD (Japan, South Korea, Australia and New Zealand), they find the opposite is true: radiative forcing related to consumption is much greater than production-related forcing. The authors suggest that policymakers in countries that are net exporters of emissions-intensive goods could consider whether some of the costs of more stringent local environmental regulations can be passed on to consumers in net importing regions.