Global trade

A new model maps out “hot spots” for greenhouse gases and unhealthy air, and connect these hot spots to consumers in many countries. The idea is to help governments, industries and individuals target areas for cleanup. The original press release by Nancy Bazilchuk can be found here.

Global trade has changed the way the goods we buy are made: in the 1970s, a majority of goods were purchased in the same country where they were produced. Today, cheap shipping and global outsourcing mean that more and more of what Western consumers buy is produced far away. The model locates spatially environmental impacts on the production side and link that to global supply chains on the consumer side. The map below shows the changing US CO2 footprint around the world between 1970 and 2008. Red hotspots illustrated where the US carbon footprint has increased, and in blue, decreased. The carbon footprint has gone down in some parts of the US, UK, and other places in Africa and Eastern Europe, while new emissions hotspots have emerged in growing US cities, Mexico, Europe, and throughout Asia.

Finding the where and the what

Solving environmental problems like climate change or air pollution is extremely difficult because they result from many small actions. Think of your mobile phone. You as a consumer buy one.  A company (almost certainly in Asia) makes it. Companies across the globe supply materials to those phone manufacturers so they can assemble them into a mobile phone. All of these individual actions have environmental impacts in all those different countries. Governments and regulators can pass laws to control pollution from the phone manufacturer, but if you really want to clean up the impact of your phone, you’d have to figure out exactly what and where in the world all those other impacts actually are.

Developing a spatial footprint model is a way to put all of the pieces together by combining maps of observed environmental impacts with an economic MRIO model. That means a company, individual, or government can find the actual locations where their supply chain emissions occur, thus creating new opportunities to participate in reducing the emissions at that place. Once you connect the environmental impact to a supply chain, then many people along the supply chain, not only producers, can participate in cleaning up that supply chain.

As an example, government regulators can only control the producers whose products cause environmental problems in Indonesia. But if the EU wanted to look at its role in causing those problems in Indonesia, they could look at the maps produced by the researchers and see what kind of impacts EU consumers are having on that country, and where they are falling. The EU could decide to adjust their research programmes or environmental priorities to focus on certain hot spots Southeast Asia. Companies could also use these maps to find out where their environmental impact hot spots are, and make changes.

The same approach also allowed them to locate hotspots for air pollution more generally and species threats.


Keiichiro Kanemoto, Daniel Moran, Edgar Hertwich. “Mapping the Carbon Footprint of Nations” Environmental Science & Technology, 50(19), pp.10512-10517, 2016.

This paper was mentioned as an Editor’s Choice in Science:

Daniel Moran, Keiichiro Kanemoto. “Tracing Global Supply Chains to Air Pollution Hotspots” Environmental Research Letters, 11(9), 094017, 2016.



Postdoctoral Researcher Daniel Moran, Postdoctoral Researcher

December 18, 2017

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