SDD can be considered a ‘successor’ of the notion of International Environmental Diplomacy (IED) and originates from three parallel shifts in international environmental politics: (1) from environment to sustainability; (2) from government to governance; and (3) from classical to new diplomacy. Since the UNCED Conference in Rio de Janeiro in 1992, so-called environmental problems can no longer be studied and managed in isolation; they need to be considered in their socio-economic and political contexts. In other words, we need to focus on sustainability instead of the environment. Secondly, non-state actors like NGOs and businesses have become ever more prominent in (international) politics and policy making, which is expressed by the term ‘governance’. A similar development, thirdly, can be observed in the world of (international) diplomacy. So-called ‘non-traditional diplomatic actors’ play crucial roles in sustainability diplomacy today. Without them, historical outcomes like the Paris Agreement on Climate Change can neither be understood nor achieved.
The term ‘SDD’ comprises new types of diplomacy which emerge on – amongst others – sustainability issues, sometimes referred to as the ‘new’ diplomacy, ‘inclusive’ diplomacy, ‘informal’ diplomacy or ‘guerilla’ diplomacy. These terms refer to other ways of doing international negotiations than through the traditional, nation state, foreign affairs and international security oriented diplomacy. Some authors claim that this ‘new’ diplomacy is very different from the traditional one. It is multi-actor (including non-state actors in international negotiations), multi-level (local issues and actors do appear at international negotiation tables, just as global issues and actors do), multi-rule (soft law is currently considered as relevant as hard law) and multi-sector (going beyond security issues and single issues, an example being sustainable development). Indeed, non-state actors are now allowed to play their roles in international diplomacy (think about environmental NGOs and their impact on international treaties), whereas private or public-private instruments to address sustainability issues are emerging (e.g. certification schemes for sustainable products, payment for ecosystem services, REDD+, etc.).