International environmental regimes involve complex interactions between the parties, their subnational jurisdictions, their citizens and, sometimes, other stakeholders. In practice it often takes several rounds of negotiation before an effective regime emerges. Even then, implementing an MEA at the national level and monitoring its progress at the international level are not simple matters. Among other things they require continual adjustment of the regime—the result of intensive further research on the environmental problem, and on the regime's effectiveness—and of public debate on the results of the research.

International environmental regimes are based on consent. Only the PIC Convention has an elaborate dispute settlement structure, reflecting the fact that it is designed primarily to manage trade in certain hazardous substances rather than protect a specific environmental resource. It is widely recognized that coercion is not a sound basis for environmental policy. Therefore, just as countries use criminal penalties to enforce environmental laws only in cases of extreme disregard, so too do international environmental regimes use coercive dispute settlement only on rare occasions. Most of these cases tend to be disputes over shared waters in regional or bilateral agreements.

Transparency and participation are arguably the most important implementation tools of international environmental regimes but implementation may need the help of an arm's-length agency. Since NGOs can go where governments sometimes fear to tread, they can be critical of countries' internal implementation of MEAs and exert pressure on their own governments for good faith compliance. Scientifically based assessments of environmental developments provide the foundation for most of these agreements, and all of this activity depends on a free flow of information and ready access to decision-making in the regime.

2.4.4 MEAs: Trade measures in MEAs