The present book is most welcome. This is in part because sufficient attention has not been paid to effectiveness in the past. The book shines a spotlight on the efforts of negotiators and lawyers to frame legal instruments with environmental objectives, together with strategies and mechanisms to ensure their effective fulfilment.

Recently, there has been an increased focus on the assessment of the effectiveness of legal and policy instruments in achieving their intended goals. In this context, the Paris Agreement on Climate Change provides one example of the need, expressed by states, to plan periodic meetings to collectively assess the overall efforts of mitigation, adaptation and other implementation measures.

That being said, we should remember that measuring the effects of the intended objectives is a rather difficult task. The question we might ask is: what exactly should be assessed? Should the results of a collective framework be evaluated or, rather, the various measures taken to ensure the effective implementation of an instrument? The latter might provide good indicators of the best road to follow in achieving a given objective. In addition, there is a need to define the methodology for assessing the effectiveness of an instrument clearly; the law has to partner with other disciplines in this respect.

Synergies among multilateral environmental agreements may contribute to greater effectiveness. Environmental issues are interdependent and there is an acute need to adopt a holistic approach towards the protection of the global environment, now more than ever. Climate change, the protection of the ozone, biodiversity and desertification regimes, to name but a few, are all closely linked and these interconnections need to be taken into account when measuring effectiveness.

The essential relationship between effectiveness and sustainability must also be subject to scrutiny. Sustainability cannot exist without the sound protection of the environment. As such, there is a need to better grasp the notion of effectiveness in the environmental field, so as to ensure the promotion of sustainable development.