Visualizing the change of embodied CO2 emissions along global production chains

Network analysis has become one of the most widely used tools for visualizing the major inter-country/inter-industry CO2 emission flows along the global production chains. Based on the World Input-Output Database (WIOD), we estimate worldwide CO2 emission flows across economies from 1995 to 2011, and visualize the major flows and their temporal changes through network analysis. More specifically, we adapt the recognition of crucial nodes in network, and present four types of networks: networks based on absolute size and relative size of CO2 emission flows for four individual years (1995, 2000, 2007, and 2011) and networks based on absolute change and relative change of CO2 emission flows for three sub-periods (1995-2000, 2000-2007, and 2007-2011). The results highlight the different roles economies play in worldwide CO2 trade networks and their temporary changes over time. While “large” economies such as the U.S. and China were often recognized as the major importers of worldwide CO2 emissions, the very rapid growth rates of a series of “medium” and “small” economies, such as Turkey, Mexico, and Cyprus, in CO2 imports throughout the entire period of 1995-2011 are not negligible. The global warming mitigation requires joint inputs from “large” economies as well as “medium” and “small” economies.