Global public goods are public goods that have a fairly universal impact on a large number of countries (covering more than one group of countries or regions), people (affecting several, preferably all, population groups), and generations (extending to both current and future generations, or at least, meeting the needs of current generations without jeopardizing the development options and opportunities of future generations). Simplified, global public goods are goods that are in the global public domain.

Some goods, such as the moon light or the atmosphere, have always had the property of global publicness. Other public goods have over time changed from being a local or national public good (or "bad", if they have negative effects) to being more global in the span of their benefits or costs. For example, various communicable diseases, such as HIV/AIDS, have spread as advances in transportation have allowed people to move more easily and to travel ever-longer distances. Or, to the extent that capital controls were removed so that cross-border financial flows increased, the contagion effects of financial crises could also spread more easily and widely. And due to improved means of communication, information, knowledge and ideas could also circulate more readily, affecting local stocks of knowledge or local and national social norms and cultures.

With increased openness of national borders, the public domains of countries have become interlocked. As a result, the availability today of a public good at the local level somewhere, often depends not just on domestic policy actions alone, but also on events and policy choices made elsewhere.

[For more on this point see the concept chapter by Inge Kaul and Ronald U. Mendoza. ]