While International Courts do not have the clout to execute several of the decisions that they give judgement upon, they are an invaluable forum for highlighting sins of omission and commission by individuals, organisations and governments. Treehugger has this very interesting piece about an International Environmental Court proposed by a British lawyer at: http://www.treehugger.com/files/2008/12/international-environmental-court-proposed-by-british-lawyer.php
While they admit, themselves, that some prominent recent legal environmental action has not gone anywhere, I think this is a superb idea from a moral perspective. Pollution hurts people across national borders - there has to be a beginning somewhere to show polluters and those otherwise harming the environment that they are wrong. Many religious and secular groups have taken environmental issues on - in recent US elections, the torch for environmentalism has been carried quite strongly by evangelical Christian groups in recent months. It would not hurt, then, to have a legal dimension to this by having an international environmental court. Hopefully, in time, this could set an example and help the world's antions build their own environmental justice systems.