The significance of international and cross-sectoral material flows in national GHG emission targets: a case study of Al

The Paris Agreement has established the Nationally Determined Contributions (NDC) as greenhouse gas (GHG) emission targets to be submitted by member countries of the United Nations Framework Convention on Climate Change... [ view full abstract ]

The Paris Agreement has established the Nationally Determined Contributions (NDC) as greenhouse gas (GHG) emission targets to be submitted by member countries of the United Nations Framework Convention on Climate Change (UNFCCC). In the NDCs, each country determines their national GHG emission reduction target for a country-selected timeframe post-2020 and lays out preliminary roadmaps towards achieving that target. This study investigates the significance of international and cross-sectoral material flow in the NDCs submitted by China and the U.S., where over 40% of global anthropogenic GHG emissions take place. Such significance is exemplified in a case study of aluminum. Aluminum production currently contributes to 1% of global GHG emissions, and global aluminum production is projected to grow substantially in the next few decades, as developing countries increase their aluminum consumption for buildings and infrastructure, while automobile manufacturers worldwide begin to use increasing amounts of aluminum for vehicle lightweighting, which provides opportunities to reduce GHG emissions through improved vehicle fuel economy over the lifetime of the vehicle, thereby reducing its life cycle GHG emissions. Moreover, in light of international trade of aluminum and aluminum products, it is likely that the GHG reductions attributed to the end use of aluminum products will occur in a different country from where aluminum is produced. This study analyzes historical and future aluminum flows on both national and global levels, evaluates GHG emissions associated with aluminum production and use, and provides insight into potential burden shifting resulting from international and cross-sectoral aluminum flows in the context of NDCs.