Abstract:
The problem of invasive alien species (IAS) is the second biggest threat to biodiversity after loss of habitat. The introduction and spread of IAS can also be a source of transboundary environmental harm. Although customary international law obliges States to prevent transboundary environmental harm, international law does not clearly articulate these obligations in the context of IAS. A potentially helpful mechanism lies in the use of transboundary environmental impact assessment and risk analysis. However, the operation of these processes, within international environmental law, international quarantine law, and international trade law has generated obligations that largely remain soft, ill-defined and inconsistent. This situation is counter productive to preventing or minimizing transboundary harm caused by IAS.
