In the last decade, international investment law has undergone an explosive growth, which is characterized by the proliferation of Bilateral Investment Treaties (BITs) and a growing number of investment-treaty arbitrations. The effect of BITs on developing countries (host states) can be far-reaching. There are cases when host states attempt to pursue the objectives of sustainable development have interfered with investments of foreign investors, and subsequently have violated BITs. Increasingly, the claim is made that broader societal interests, such as sustainable development, should be incorporated into BITs. In this article, important trends on the role of sustainable development in international investment law are analysed. Examples of states that attempt to incorporate sustainable development in their BITs are compared with states that oppose such reforms. This comparison shows that there is a lack of consistency and consensus on the future of the role of sustainable development in international investment law.
