This article is written by Aglaé Jézéquel.
One of the most unexpected outcomes of COP21 was the inclusion of the 1.5°C threshold on global temperature warming in the Paris agreement. More precisely, the article regarding the purpose of the agreement goes as follows: “Holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 °C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change.”
The ancestor of 1.5°C was the 2°C temperature threshold, which was agreed upon during COP15 in Copenhagen. It was supposed to materialize a limit over which climate change would become unpredictable and out of control. This choice was mainly political, although the history of the 2°C threshold has been a series of exchanges between science institutes and policy makers. The 2°C temperature threshold was one of the rare points that brought consensus inside the UNFCCC and one of the only achievements of COP15. The Copenhagen Accord “recogniz[es] the scientific view that the increase in global temperature should be below 2 degrees Celsius”. The last paragraph of the accord refers however to 1.5°C as a point of agenda for the next steps of international climate negotiations: “This would include consideration of strengthening the long-term goal referencing various matters presented by the science, including in relation to temperature rises of 1.5 degrees Celsius.”
Until COP21, this threshold was mostly supported in the negotiations by the Alliance Of Small Islands States (AOSIS), and not taken very seriously by other Parties. Nevertheless, during the Paris conference, the 1.5°C threshold gradually got more and more supporters until it was included in the final version of the Paris agreement. This has been glorified by many NGOs and Parties as some sort of negotiation miracle which proved the ability of the UNFCCC process to lead the world to an ambitious action agenda on climate change -or at list as the first step in the right direction. Most representatives of NGOs immediately celebrated the come back in the spotlight of the 1.5°C threshold, and seized the opportunity to actively (and successfully) push for its inclusion in the final text.
So what are the reasons for this shift? There is no certainty that 2°C is safe or that there will be no surge in climate change on the road to this threshold. Indeed, scientists have been studying the possible physical mechanisms leading to tipping points, moments when the system does not react linearly (for example, a sudden complete melting of Greenland, or the complete disappearance of the Amazonian Forest) but have been at a loss when it comes to predict if and when they could happen. Even without considering those threats, it is clear that 1.5°C would be much safer. It is stated by IPCC scientists and explored in the 2 year review released in June 2015 in Bonn by both the SBI and the SBSTA.
With all that said, it really seems like advocating for the 1.5°C threshold is the good thing to do, and the NGOs -the usual “good guys” in the climate negotiations movie- have been doing just that.
How a global temperature threshold does not translate into an efficient implementation
But what does such an objective imply? Is it really possible to achieve 1.5°C? According to a recent article of Kevin Anderson in Nature geoscience “Of the 400 scenarios that have a 50% or better chance of no more than 2 °C warming (with three scenarios removed due to incomplete data), 344 assume the successful and large-scale uptake of negative-emission technologies. Even more worryingly, in all 56 scenarios without negative emissions, global emissions peak around 2010, which is contrary to available emissions data.” And this is only for the 2°C threshold. Staying below a 1.5°C warming implyes to rely on geo-engineering and it would be healthy to recognize this, when we defend this ambition in the UNFCCC arena. There is an open door for that in the Paris agreement as the long-term is to “achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases”
It also would have huge implications for the world economy. It would require huge changes happening not tomorrow but now, in every single country in the world. Sometimes, we present climate change as the ultimate limit, the thing to avoid at any cost. But what is this cost? Can we reach a 1.5°C world without sacrificing food security, access to drinkable water, better life conditions for everyone on Earth, and development in countries which are currently increasing the level of life of their inhabitants?
It is dangerous to communicate on a goal which is either unreachable, either dependent on very controversial technologies. Even if we consider that the people inside the UNFCCC are conscious about how unrealistic such a goal is, nobody explicitly says 1.5°C is just a rhetoric object born out of negotiations disconnected from the reality. It is a lie to all the people who do not have the cynical background of climate regulars. In my opinion, it is dishonest and cruel.
We often argue that the negotiations are disconnected from reality, but it is also up to us to ground them in reality, and it can start by admitting that writing 1.5°C on paper is making the whole process look even less credible.
A diplomatic strategy?
If we forget the unrealistic diagnostic we just made and consider this 1.5°C as just a diplomatic move in a very complex chess game of negotiations, I am again puzzled and struggle to find the logic behind this move. Through talks with different observers, the usual answer I get to my concern is that by being more ambitious, we might not avoid a 1.5°C warming but give a stronger impulse to climate action than we had with just 2°C. Maybe this is true, considering that those thresholds have anything to do with giving a steady momentum to mitigation, or that non-state actors will be influenced by such a bold change. On the other hand, how much time does it take in time limited negotiations ? Could the agreement have been more ambitious on the issues of finance, differentiation, adaptation, long-term goal or loss and damage if the most vulnerable countries had not spent so much time to fight for a more ambitious temperature limit than the 2°C on which everybody had already agreed ?
This might all come down to compensation, and trying to attribute the loss and damage in regards to a 1.5°C rather than a 2°C. This would however be extremely cynical, and is not likely to happen seeing how any interpretation of loss of damage in regards of liability or compensation has been cast out by the US, resulting in paragraph 52 of the COP decision: “Agrees that Article 8 of the Agreement does not involve or provide a basis for any liability or compensation.”
Yet, my biggest concern regarding the 1.5°C threshold-which is applicable to 2°C too- lies in the future. What will happen when the global temperature exceeds 1.5°C ? What kind of a message regarding the capacity of the world to face climate change will it send ? How will the UNFCCC, the NGOs, and all the climate stakeholders react to that cold shower?
About the authors: Aglaé Jézéquel « I am a phD student in climatology, working specifically and the detection an attribution of extreme events. I am a member of CliMates since 2013. I have followed UNFCCC negotiations with CliMates team several time.