COP 16 ended with the adoption of the Cancún agreements, even if consensus was not reached. Actually, the UNFCCC does not have formal voting rules, Parties were indeed not able to agree on which kind of rules was worth adopting during COP 2 and options remained only on paper (Art. 42). The consensus rule was then assumed as custom (a somewhat elastic term that in practice has required only the lack of formal objection by one more parties, rather than unanimous agreement), which could therefore evolve over time.
COP 2 and COP 15 represented in themselves exceptions, since Parties “took note” of the produced agreement and declarations without having reached consensus on them. The Geneva Declaration actually marked the first time that countries were willing to act in the absence of consensus (Bodansky, 2009).
Cancún represent a different situation, since the documents were not noted but adopted in the absence of consensus. Would this set a precedent for climate change negotiation within the UN system? Why a similar decision was not taken at Copenhagen? As regards the first, time will be needed to redefine new customary rules. As regards the second, the outcome of COP 16 was challenged only by one country (Bolivia), while the Copenhagen Accord was opposed by a group of six countries. Numbers could make the difference. Also, Cancún had the more or less outspoken goal of proving that the UN was able to be the fundamental venue for climate change negotiations and Mrs. Espinosa had to provide public and political opinion with an outcome."Moving forward" has this time substitute the "reaching consensus" mantra.