This Saturday, December 12, COP21 President Laurent Fabius announced the goal of "containing the temperature increase to well below 2°C and striving to maintain it at 1.5°C, which would significantly reduce the risks and impact of global warming." An announcement which echoed with worldwide social media opinion: only 43% considered that limiting warming to 2°C would be sufficient for the planet.
Limiting climate impact
Small island states are adamant: they will not sign the Paris Agreement without mention of the 1.5°C threshold. As has been noted by many Internet users, it is the most vulnerable countries which will suffer the first effects of climate change
The "High ambition coalition", led by the Marshall Islands, has long fought to reach such a figure and is just one of many to voice opposition at the arbitrary nature of the 2°C threshold set at Copenhagen. Analysis of social network exchanges provides us with a reminder that the objective is indeed attainable since it is supported by a majority of countries.
Revising the target by just half a degree by 2100 may have more of an impact than one could imagine. By limiting temperature increases to 1.5°C, heat waves are expected to be less devastating and declining crop yields limited, say IPCC experts. As for the oceans, the same objective would prevent coral bleaching and the extinction of large reefs. The last IPCC report states that a 2°C scenario would cause massive melting of the Greenland ice sheet, causing sea levels to rise by 0.5 to 1 meter by 2100. With the lower option, however, it should still be possible to avoid this nightmare scenario.
A utopian goal?
"Do we have the technologies to stay under 1.5°C?" wonder internet users. A report by the United Nations Environment Programme (UNEP) published in 2015 shows that humanity can emit 450 billion tonnes of CO2 and still have a chance of staying below a 1.5°C rise. Unfortunately though, climate science isn’t accurate enough to link a given level of emissions to a possible temperature increase.
In addition, some users are questioning the States’ commitments for emissions reductions. Though they are ambitious, are they sufficient? The first revisions which could reinforce these promises will not occur before 2020. By then, scientists estimate the level of CO2 emitted into the atmosphere will be too high to avoid breaching the 1.5°C limit. Or is the ambitious target announced simply a way to encourage States to take more appropriate measures, and to make the necessary investment to have a real impact?