COP21 ends with agreement to limit and reduce emissions, will it work?

Fred Pearce from ENN

Climate negotiators meeting here in Paris have achieved a deal that could change the world. Conference chair and French foreign minister Laurent Fabius crowed that he had presided over a "historical turning point." Even when the hype has died down, that may turn out to be true. Even climate scientists who on Friday had sharply criticized an earlier draft of the text were convinced.  

The Paris Agreement commits the world to capping global warming to "well below 2 degrees Celsius above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 degrees C." To achieve that, it requires the world to "reach global peaking of greenhouse gas emissions as soon as possible" and "to undertake rapid reductions thereafter, in accordance with best available science." 

The intention is to reduce net greenhouse gas emissions to zero "in the second half of this century." That is, any emissions would have to be balanced by uptake by nature or some future technology for soaking up greenhouse gases from the atmosphere. 

"This agreement is a turning point," said Johan Rockstrom, director of the Stockholm Resilience Center and architect of the science that looks at "planetary boundaries" within which society may safely work.  

The day before the final deal was done, climate scientists here had ripped into a penultimate draft, saying its temperature aspirations were admirable, but were made meaningless because they were not matched by mechanisms for reaching them. "Diplomats understand the economics, but not the science," said Kevin Anderson, of Manchester University, England. 

But in the final hours, science was added to the agreement to put some numbers on reaching the aspirations. It did not bridge the gap between aspirations and pledges, but it shone a light on the gap that had to be filled and offered some opportunities for when it might be narrowed. 

The final version noted that the emissions pledges from the 184 nations that form the heart of this agreement would lead to global emissions of 55 gigatons of greenhouse gases in 2030. But that, it said, fell far short of the reduction to 40 gigatons a year needed for limiting warming to two degrees. It added that the even lower levels of emissions necessary to secure 1.5 degrees had yet to be determined.