Some problems in the COP21 negotiating text of Wednesday December 9
There are two options in the text to formulate the long-term goal that operationalizes the 2/1.5oC temperature limit:
Option 1: Parties collectively aim to reach the global temperature goal referred to in Article 2 through [a peaking of global greenhouse gas emissions as soon as possible, recognizing that peaking requires deeper cuts of emissions of developed countries and will be longer for developing countries; rapid reductions thereafter to [40–70 per cent][70–95 per cent] below 2010 levels by 2050; toward achieving net zero greenhouse gas emissions [by the end][after the middle] of the century] informed by best available science, on the basis of equity and in the context of sustainable development and poverty eradication.
Option 2: Parties collectively aim to reach the global temperature goal referred to in Article 2 through a long-term global low emissions [transformation toward [climate neutrality][decarbonization]] over the course of this century informed by best available science, on the basis of equity and in the context of sustainable development and poverty eradication.
The advantage of the first option is that it specifically mentions the net zero GHG emissions target that needs to be met for a 2oC limit by the end of the century, according to IPCC AR5 and repeated in the UNEP Emissions Gap report 2015. This is much clearer than the formulation in option 2 that talks about “climate neutrality”. That climate neutrality wording also leaves open the possibility of meeting this target by large-scale insertion of aerosols in the upper atmosphere (geo-engineering). The “decarbonisation” wording in option 2 is in fact incompatible with a 2oC limit: for all GHGs to be net zero by the end of the century, CO2 emissions should already be net zero much earlier: between 2060 and 2075 (see UNEP Emissions Gap Report 2015). And for a 1.5oC limit that many countries favour, the net zero CO2 emissions should already be reached by 2050. The decarbonisation language is therefore wrong.
The so-called ambition mechanism is necessary, since the collective effect of the submitted INDCs is at best limiting the long-term temperature increase to 3-3.5oC (UNEP Emissions Gap report 2015). The Emissions Gap in 2030 is estimated to be 12-14 GtCO2e. Waiting to 2025 or 2030 with strengthening the mitigation efforts is a sure way to miss the 2oC limit.
The text of the agreement addresses this in 3.6 by emphasizing progression in subsequent INDCs. In 3.8 a 5 year cycle is mandated, but only after the first so-called stocktake that article 10 sets for 2023 or 2024. And 2bis.4 adds another barrier, i.e. it says that successive INDCs will be communicated before the expiry of the previous INDCs. In other words, for INDCs that only have a target for 2030, like the EU, a new INDC would only be required after 2030.
3.6 Each Party’s successive ### [shall][should][will] represent a progression beyond the Party’s previous efforts and reflect its highest possible ambition [based on common but differentiated responsibilities and respective capabilities, in light of different national circumstances].
3.8 Parties shall communicate an ### every five years in accordance with decisions of the CMA being informed by the outcomes of the global stock take referred to in Article 10.
2bis.4 Successive [intended] nationally determined contributions will be [informed by the result of the global stocktake as defined in Article 10 of the Convention] and communicated before the expiry of the previous [intended] nationally determined contribution by the Party concerned.]
Decision II.20 adds another requirement to have a first stocktake before the new agreement enters into force in 2020, namely a “facilitative dialogue” in 2018 or 2019, without any stipulation that such a stocktake should lead to strengthening the INDCs.
Decision II.20 [[Decides][Invites the President of the COP] to convene a facilitative dialogue among Parties to take stock of the collective efforts of Parties in  in relation to progress towards the long-term goal referred to in Article 3, paragraph 1, of the Agreement and to inform the preparation of INDCs pursuant to Article 3, paragraph 8, of the Agreement;]
And, surprisingly, decision II.17 states that “greater emission reduction efforts .. will be required in the period after 2025 and 2030…”. This is a sure way of missing the 2oC limit (let alone a 1.5oC limit), because it would then be impossible to close the very big 2030 emissions gap mentioned above. Strengthening efforts should happen much earlier, even before 2020 to have a chance of returning to a 2oC trajectory.
Decision II.17 Notes with concern that the estimated aggregate greenhouse gas emission levels resulting from the INDCs in 2025 and 2030 do not fall within least-cost 2 ˚C scenarios, and that much greater emission reduction efforts than those associated with the INDCs will be required in the period after 2025 and 2030 in order to hold the temperature rise to below 2 ˚C or 1.5 ˚C above pre-industrial levels;
Then there are two other elements that could have an impact on the strengthening of ambition. Article 2bis.3 is a disclaimer for developing country INDC implementation and strengthening by referring to ill-defined “implementation of developed country Parties of their provision of finance and technology”. Without having an agreed level of support for individual INDCs this is an open invitation to do less.
2bis.3 The extent to which developing country Parties will effectively implement this Agreement will depend on the effective implementation by developed country Parties of their commitments on the provision of finance, technology development and transfer and capacity-building.
The second element is an invitation to countries to develop and communicate long-term low-emissions development strategies. This would be helpful for countries to strengthen their INDCs, but by making it purely voluntary and not connecting it with financial and technical support this is currently a very weak provision.
3.21 All Parties should voluntarily formulate and communicate long-term low-emission development strategies.
All in all, the conclusion must be that the ambition mechanism in the current text is still very weak.
December 9, 2015
 UNEP Emissions Gap Report 2015, http://uneplive.org/media/docs/theme/13/EGR%202015_Technical%20Report.pdf