Two of the most critical weeks in the calendar ahead of the 21st Conference of the Parties (COP) to the UN Climate Change Convention have commenced. The formal negotiations in Bonn, scheduled from 1st-­-11th June 2015, will play a decisive role in determining whether an effective, durable and flexible legal agreement is reached six months’ later in Paris. The Bonn meeting will provide the first opportunity for the negotiating text to be considered in a formal setting.

The Bonn negotiations follow several informal negotiation sessions over the past three months. In Lima in March 2015, there was a broad consensus that the Paris Agreement should consist of an underlying legal instrument complemented by a series of COP Decisions to flesh out the details. By contrast, there was no such alignment on how and where in the Agreement to inscribe the Parties’ Nationally Determined Contributions (NDCs). This issue will certainly be addressed in Bonn; its resolution, however, remains uncertain given the divergence of views as to the legal effect that Parties’ mitigation commitments should have. In particular, the US has indicated that it would prefer to keep the NDCs outside the Paris Agreement so that they are not legally binding at international level.