Scientists have revealed that if one major economy take the lead and have other nation's follow, global warming can be kept below two degree Celsius.
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Scientists have found the amount of emissions reductions it takes for a major economy to lead out of the climate gridlock.
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Lead author Malte Meinshausen of the University of Melbourne said that 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.
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Meinshausen said that their analysis showed that economies would have to roughly double their current domestic 2030 emissions reductions targets, which would certainly require substantial efforts.
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A key factor to address is the two conflicting fairness criteria: one favoring 'distributive justice' leading to per-person emissions to be about the same for every nation by 2050, the other leaning toward 'corrective justice' and factoring in past emissions to obtain equal per-person cumulative emissions. On board the first criterion are the Europe and U.S., with China and India for the second one.
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In this scenario, the US national emissions reduction target would have to be roughly 50 percent instead of currently 22-24 percent below 2010 levels by 2030.
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Alternatively, the equivalent target for the Europe would have to be about minus 60 percent instead of currently 27 percent below 2010.
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If China wanted to assume leadership, China would have to reduce emissions by 32 percent below 2010 levels by 2030. In a scenario of equalized cumulative per-capita emissions, it would only need to reduce them by 4 percent. This seems little, but would in fact be a most crucial contribution.
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Researchers said that their study thus anticipated the upcoming Paris climate summit, which would see countries make their mitigation contributions in an independent bottom-up manner.
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Joeri Rogelj of the International Institute for Applied Systems Analysis said that their study introduced an important new concept which helps them understand how major countries could still assume a leadership role on this highly fragmented playing field.
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The study appears in the Journal Nature Climate Change.
