Two degrees too much

The Structured Expert Dialogue (SED) of the 2013-2015 Review gained important Presidential attention yesterday. At the beginning of the meeting, COP President Vidal stated that the SED is the most important space to reconcile science and policy. He continued in mentioning the mandate of the 2013-2015 review – which is to consider the adequacy of the long-term goal and progress towards achieving it – meaning that clear answers must result from the review for the Paris decisions.

On the first task to consider, the adequacy of the 2°C limit, yesterday’s meeting gave clear answers from science. If temperature increases are limited to below 1.5°C, there are more chances for adaptation.

One example is the coral reefs provide crucial sources of protein in many peoples’ diets. Coping with warming of 1.5°C is already a severe challenge for corals, but they will struggle to survive with 2°C warming. Also, ‘below 1.5°C’ could mean a chance to protect the summer Arctic sea ice.

It’s not only ecosystems or sea ice in danger with 2°C warming, but people are also vulnerable. Cultures of Arctic communities and those on low-lying lands are endangered: for them the risk is high with 2°C.

It was good to hear yesterday that the US is interested in better understanding the differential risk of a world that is 1.5°C warmer and one that is 2°C warmer. AR6 of IPCC could deliver new insights on that, and ECO hopes this is the beginning of a real willingness to act on science-led mitigation ambition.

Of course the SED did not only look at the risks of climate change but also at mitigation opportunities. The scientists state that a fundamental departure from BAU is necessary for a 2°C-trajectory. For that, there is a need for carbon removal technologies (CDR) in the second part of the century, unless we make a steep change in emissions reductions by 2050. As we don’t really know what CDR is, how it works and which risks are associated with it, this is another convincing argument to begin effective and expeditious mitigation promptly.