Most countries agree we must limit global warming to 2 degrees Celsius in order to keep its effects from becoming catastrophic, but are not on the same page about what we need to do to achieve this. New research suggests that if one major economy takes the lead in fighting climate change, others will likely follow without having to agree on particulars.
Greenhouse gas emission reductions will be the focus of the world climate summit COP21 in Paris, and the outcome of the meetings could have a major impact on the future of our planet, Potsdam Institute for Climate Impact Research reported. The findings were made by analyzing a number of IPCC databases.
"If either the European Union or the US would pioneer and set a benchmark for climate action by others, the negotiation logjam about fair burden sharing could be broken," said lead author Malte Meinshausen from the Potsdam Institute for Climate Impact Research and the University of Melbourne. "Our analysis shows that they would have to roughly double their current domestic 2030 emissions reductions targets - which would certainly require substantial efforts. Yet it seems to be one of the few options to stay on track for eventually limiting warming below 2 [degrees Celsius] and fend off a drastic increase of weather extremes and sea-level rise."
The world is basically divided into two major "camps" when it comes to climate change mitigation: the first (including the U.S. and E.U.) believe in "distributive justice," in which emissions per person would be roughly the same in every country by 2050; the other camp (including China and India) believe in "corrective justice," in which countries that emitted more in the past must emit less in the future and vice versa. Experts have pointed out that countries tend to join whichever camp would require them to reduce their emissions the least. China and India were industrialized more recently than the U.S. and E.U., so their past emissions are not as high. Today China emits more than the U.S. and E.U. combined.
"Now we have calculated how much a major economy would have to cut its greenhouse gas output if all the other countries would follow the emissions allocation scheme that is most [favorable] to them - so some base their reduction number on the equal per capita scheme, others include the historical emissions, and still the 2-degree limit is met," said co-author Louise Jeffery from the Potsdam Institute. The scientists call this concept diversity-aware leadership. "This seems less utopian than a uniform regulation. But it builds on the assumption that most economically relevant countries participate in one way or another and ensures that the global efforts are successful in limiting warming to 2 degrees."
Under this scenario, the researchers calculated the U.S. would need to reduce emissions to 50 percent of its 2010 levels by 2030, instead of the 22 to 24 percent reduction currently being considered. China could also take the lead and make a major contribution to the fight against climate change, but the researchers believe this is unlikely to happen. If China were to take the lead, they would need to get emissions to 32 percent below what they were in 2010 by 2030; under an equalized cumulative per-capita emission strategy they would only need to reduce them by 4 percent.
"If you look at what pledges the countries put on the table for Paris so far, it's clearly not enough to keep warming within the internationally agreed 2-degree limit - hence the current 'intended nationally determined contributions' can only be regarded as a first step in the right direction," said co-author Sebastian Oberthuer from Vrije Universiteit Brussel. "If we postpone action until we have universal agreement on a fair allocation of emissions reductions," he says, "the result will be fair only in that everybody will lose - because climate change will hit us all."
The findings were published in a recent edition of the journal Nature Climate Change.
