"International arbitrators must be prepared to grapple with complex environmental issues, and to apply legal principles that are constantly evolving in response to changing scientific, social, and economic conditions."

These lines were written by Oscar Schachter in his book "International Law in Theory and Practice," published in 1991. That is, before the Earth Summit, known as the Rio de Janeiro summit, and before the Kyoto protocols. Environmental issues seem to have always been relevant for international arbitration, however, in recent years there has been very an increase of disputes and significant developments.