A new study published in Nature Climate Change analyzes the national climate targets needed to meet the 1.5 and 2°C goals according to five different equity principles, and how these compare with the current climate pledges.
Benchmarks to guide countries in ratcheting-up their ambition to remain well-below 2°C and pursue 1.5°C in an equitable manner are critical but not yet determined in the context of the Paris Agreement.
The study's lead author PhD candidate Yann Robiou du Pont, of the Australian-German Climate & Energy College at the University of Melbourne said that following the equity categories outlined by the IPCC, we show that the G8 and China together could close the emissions mitigation gap to keep warming to below 2°C.
"However, equitably limiting warming to 1.5°C would require individual countries to achieve mitigation milestones like peaking emissions or reaching net-zero emissions much earlier," adds Mr Robiou du Pont.
"Our study presents for the first time emissions allocations of global cost-optimal emissions pathways consistent with the Paris Agreement goals, in particular the 1.5°C goal."
"Equity refers to the fairness and comparability of climate pledges. Fairness can be interpreted in many ways; our paper quantifies these different interpretations so that the quantitative implications can be compared," co-author Louise Jeffery of the Potsdam Institute for Climate Impact Research adds.
"Equity concepts include those that assign lower future emissions allowances to countries with high past emissions and wealthier countries, those that aim for equal emissions per person, and those that preserve the right to development and accommodate national circumstances".
The results of the study will also be available on a new website called Paris Equity Check, the first website to offer a multi-dimensional and completely peer-reviewed overview on climate pledges with regard to equity principles, consistent with the Paris Agreement.
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Yann Robiou du Pont et al. Equitable mitigation to achieve the Paris Agreement goals, Nature Climate Change (2016). DOI: 10.1038/nclimate3186