The Role of the Precautionary and Polluter Pays Principles in Assessing Compensation

投資協定仲裁は、過去二十数年の間で急激な利用件数の増加をみたが、反面、これに対する懸念および批判の高まりにより、今後の持続的発展の可能性が不透明な状況にある。投資仲裁に対するかかる不信の背景には、仲裁廷が、国の規制権限を尊重する一貫した姿勢を示さず、仲裁廷による、「外国投資保護」と「公益保護」という異なる利益間の調整が不透明かつ予測不能であったことが挙げられる。本ペーパーは、このことを前提として、実効性ある利益調整の一方法として、投資受入国による協定違反が認められた場合における損害賠償額の調整が可能かつ適切であることを、先例の検討を通じて論証し、その上で、環境問題を含む紛争において、予防原則および汚染者負担原則に照らし、損害賠償額を調整する可能性を提案する。

The upsurge of investment treaties and cases of investment arbitration demonstrates the dramatic growth of foreign investment laws in the past few decades. Also, due to the ongoing negotiation of the "mega" free trade agreements, this field of law has received an increasing amount of recognition. This recognition, however, is accompanied by a growing concern over whether investment arbitration has reduced the scope for state regulation. A major source of concern is the lack of consistency between arbitral tribunals in balancing investment protection against the public interests of host states. Against this background, this paper addresses the question of how to properly balance the interests of foreign investors against environmental concerns, focusing on the remedy phase of legal disputes. It is argued that there are cases where, even if the host state is found to have breached investment protection obligations, the awarding of full compensation is inappropriate, and this applies to those that involve difficult balancing between public interest such as environmental protection, and the protection of foreign investment. Based on these considerations, this paper proposes that the precautionary principle and the polluter pays principle—widely accepted international environmental principles—may provide other grounds for awarding partial compensation.