Although the Copenhagen negotiations failed to agree on quantity targets, Obama intervened dramatically at the last minute remove one crucial roadblock. This removal was enshrined in the unfairly maligned Copenhagen Accord.
The Copenhagen Accord changed once and for all the meaning of the FCCC principle of “common but differentiated responsibilities.” Before the accord its de facto interpretation by all developing (Kyoto, Annex II) countries was that they had no responsibility and would act only if paid to act, for example, through Kyoto’s clean development mechanism.
The Copenhagen Accord resulted in China, India and many other Annex II countries immediately pledging unilateral actions. Although these pledges are generally weak, they firmly establish the principle that all countries have real responsibilities.