Policies that regulate private transportation or household energy consumption have little impact on international trade flows, and would be implemented regardless of whether a territorial or consumption (footprint) system boundary was used for policy. Border carbon adjustments to improve the economic efficiency and environmental effectiveness of unilateral climate policies effectively change international trade flows, and thus directly affect the international component of an environmental footprint. Even though a policy on domestic transportation and a border carbon adjustment may both reduce an environmental footprint, we focus here only on the policy domain that is "additional" when switching from a territorial to footprint perspective (that is, policies that address imported flows from other countries). The term "carbon footprint" is also often misused, particularly in the media, to refer to territorial carbon emissions.