Preventing Transboundary Harm From Invasive Alien Species

The problem of invasive alien species (IAS) is the second biggest threat to biodiversity after loss of habitat. Although customary international law obliges States to prevent transboundary environmental harm such as IAS, international law does not clearly articulate these obligations in this context. 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.