Reuters: If and when a global deal to curb climate change is done in Paris this December, the matter of enforcement is likely to be left not to sanctions but to peer pressure. While legally enforceable environmental treaties do exist, experts say that some of the most effective environmental controls have come about from a shared sense of self-interest. In 1941, an international tribunal established the principle that "the polluter pays" by ordering compensation after fumes from the Trail Smelter, processing...