Climate experts: “We must aim for a zero carbon future"

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Nature Middle East, Paris, France

Less than 24 hours before the COP21’s highly anticipated final agreement is released, the world’s top climate scientists gathered to weigh up the text’s final draft, specifically regarding the temperature target. 

Negotiators at the Paris meeting made significant progress in galvanizing leaders toward a more ambitious global average temperature target: to limit the increase to "well below" 2˚C above pre-industrial levels, “recognizing that this would significantly reduce risks and impacts of climate change,” reads Article 2 of the text. 

Scientists have been pushing to prevent a global temperature rise of more than 2˚C by 2100 in order to limit carbon emissions and guard projected global warming. Previously, this became a policy target; a benchmark to limiting dangerously disruptive climate change effects. Now the text explicitly limits warming to between 1.5˚C and 2˚C, which, according to Hans Joachim Schellnhuber, the director of the Potsdam Institute for Climate Impact Research (PIK), is closer to the recommendations for a 1.5˚C limit by International Panel on Climate Change (IPCC) and the latest science. 

Schellnhuber says, however: “The text does not sufficiently operationalize the long-term goal” which is zero CO2 emissions globally by 2050, which is essential to achieve the 1.5˚C goal. Steffen Kallbekken is the Research Director at CICERO, and heads the Centre for International Climate and Energy Policy.  He noted: “the draft goal of 2˚C and pursuing efforts to limit temperatures to 1.5˚C is aspirational.” A previous draft had included in its terms 40 to 70 and 70 to 90% emission cuts, which he says, have been taken out of the current draft. “The options consistent with science were replaced by vague formulations,” he comments. 

The scientists predict that by the time the pledges of COP21 come into effect in January 2020, it’s very probable that the world will have used up the entire carbon budget required to maintain 1.5˚C warming levels. More worrying is the Intended Nationally Determined Contributions (INDCs) agreement in which countries publicly outline their post-2020 climate actions. Cumulatively, the contributions would still cause an increase in global warming between 2.7˚C and 3.7˚C - well over the 'safe' red line drawn by scientists. 

“Two degrees Celsius is a political aspiration but the INDCs are not consistent with that aspiration,” says Johan Rockström, Executive Director of the Stockholm Resilience Centre. It’s the reason why the scientists sitting on today’s panel called for an early revision of the INDCs and for reviews to take place “every two or three years” to ensure that all countries are on track towards a low-carbon, climate-resilient future.

Another contested article in COP’s final draft is Article 3, which focuses on the operationalization of the long-term goal of a decarbonized world. The text uses the term 'greenhouse gas neutrality’, which the panel scientists believe obscures the fact that CO2 emissions will have to fall to zero to stabilize warming. Some even called the term “potentially harmful.” Its vagueness, compared to older terms like “decarbonization” or “net zero greenhouse emissions” used in previous drafts, makes it open to interpretation. 

“This text is even weaker than the one that came out of Copenhagen,” says Kevin Anderson, deputy director of the Tyndall Centre for climate change research, Manchester University. He points out that the Copenhagen text at least factored in emissions produced by the shipping and aviation sectors, and these are missing from the current draft agreement. “I have heard that this text is 'practical',” he says, “but practical to whom? Maybe to wealthy people but certainly not for the global poor, particularly in the Southern Hemisphere, for whom the current text is somewhere between dangerous and deadly,” he says.

Already, some negotiators have deemed the target of 1.5 ˚C as potentially problematic; not all countries seem to be on board with it. "The 1.5˚C [target] has become more a political decision rather than a science-based one,” comments, Jamal Jaballah, director, League of Arab States. "For Arab countries, it will increase food insecurity and poverty reduction in the region, because our economies would suffer too much for such a cut in emissions." Jaballah says developing countries simply won’t be able to keep up. 

Before the conference ended, the scientists insisted that the “deal is not finalized.” “There are still 24 hours [left] to put something stronger together,” says Anderson, who reiterated that there should be a regular review on CO2 abatement and progress every two years. According to Schellnhuber, global de-carbonization needs to be completed by mid-century, if the world wants to be on the safe side. “Once we leave Paris, starting Monday, every country should immediately set up a de-carbonization plan and start implementing it,” he concludes.