The stated objective of the Copenhagen conference is to limit the average rise in global temperature to 2 ° C - not the lower of 2 ° C, as recently reported MEP Rachida Dati. The choice of this target of 2 ° C is that it is difficult to predict, given the current state of the science, impacts that occur beyond this temperature increase: the climate could therefore be potentially control, partly because of feedback loops. The objective of 2 ° C is also the opinion of many, the most ambitious goal that can reasonably be expected to attain. As such, the 2 ° C has become the official objective of the negotiations, with the blessing of Major Economies Forum.

Behind this facade of unanimity, however, not everyone agrees. On 24 October, a large share of civic engagement at the global level (www.350.org) called for stabilizing the atmospheric concentration of greenhouse gas emissions at 350 parts per million (ppm), ie say, a much more ambitious goal than is posted today - 450 ppm - in line with the objective of 2 ° C. Since long, AOSIS, the Alliance of Small Island States, claiming that the target of 1.5 ° C rather than 2 ° C. For many small islands, 2 ° C is too much. Such a temperature increase would result in an average rise in sea levels of about one meter, and then submerge many territories rendered uninhabitable.

Tuvalu yesterday, has loudly tried to argue that the 2 ° C target condemns certain territories. This claim is rhetorical posture: it has no chance of success. In light of current commitments, it is the distance to reach the 2 ° C (see post: Are we then on track to the 2°C target?). In the present context, the 1.5 ° C is unrealistic. But the island States, supported by civil society, wish to recall that it was half a degree too, which is also a way for them to raise the pressure regarding the financing of adaptation strategies that they could implement. For even halving global emissions of greenhouse gas emissions by 2050, as recommended by the IPCC, the chances of limiting temperature increase to 2 ° C are only 50%. That is to say, basically, that we play Russian roulette with three bullets left in the barrel. Tuvalu said yesterday, and was probably useful.