Warming assessment of the bottom-up Paris Agreement emissions pledges

摘要: Under the bottom-up architecture of Paris Agreement, countries pledge Nationally Determined Contributions (NDCs). Current NDCs individually align, at best, with divergent concepts equity and are collectively inconsistent Agreement. We show that global 2030-emissions match sum each country adopting least-stringent five effort-sharing allocations a well-below 2 °C-scenario. Extending such self-interested aggregation might lead to median 2100-warming 2.3 °C. Tightening warming goal country’s approach aspirational levels 1.1 °C 1.3 °C could achieve 1.5 °C 2 °C-thresholds, respectively. This new hybrid allocation reconciles nature Agreement its top-down thresholds provides temperature metric assess NDCs. When taken as benchmark by other countries, India, EU, USA China 2.6 °C, 3.2 °C, 4 °C over 5.1 °C warmings,