New study “Warming assessment of the bottom-up Paris Agreement emissions pledges”

A new study published in Nature Communications tackles the question: “How much global warming would result from the world following the ambition of a given country’s climate pledge (NDC)?”
In this study, we derive a global warming metric to assess each country’s climate pledge (NDC) based on the global warming it implies, should the rest of the world follow the ambition of that NDC. For example, the climate pledge of the US leads to a 4°C warming, while that of the EU to a 3.2°C warming.
The study is available on open access here

An interactive website makes the results available for 169 countries.
This study brings several novel insights
– The warming assessment metric is the first peer-reviewed study to provide a global warming metric to assess the ambition of NDCs from 1.2°C to 5.1°C. It provides negotiators and civil society with a novel metric, reflective of the Paris Agreement’s hybrid nature, to ratchet up ambition of NDCs under the Talanoa Dialogue, for the COP24.
– the new hybrid combination of equity approaches reconciles the bottom-up nature of the Paris Agreement with its top-down warming thresholds and provides a temperature metric to assess NDCs. It models the bottom-up architecture of the Paris Agreement where each country follows the least-stringent vision of equity and suggests an increase in ambition of the climate target to collectively stay under the the top-down warming thresholds of well below 2°C, and 1.5°C. National hybrid emissions trajectories are derived to achieve the Paris Agreement goals; with clear 2030 and 2050 targets.
– this hybrid architecture can inform climate litigation cases such as Urgenda, where the court ruled that the Dutch government should adopt at least the least ambitious end of the equity range suggested by the IPCC. By ruling for the application of the ‘hybrid’ approach suggested in our study, the court would both avoid a normative choice on the choice of a single equity and let the country follow the least stringent vision of equity, and yet rule for an emissions target consistent with the Paris Agreement warming threshold.

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