National fair shares: The mitigation gap – domestic action and international support

This report applies a generalized and transparent equity reference framework to quantitatively examine the problem of national fair shares in a global effort to rapidly reduce greenhouse gas emissions. The analysis in this report starts from a recognition that equity an equitable international agreement is necessary if we are to preserve a stable climate system. This is because equity is the key to cooperation, and cooperation is indispensable in solving any commons problem. The authors use the Climate Equity Reference Calculator, which they developed, to determine what could be considered a country’s “fair share” of the global mitigation effort, using flexibly defined national “responsibility and capacity indicators”. The framework is explicitly designed to reflect the core equity principles of the United Nations Framework Convention on Climate Change (UNFCCC). It can be applied using a range of possible assumptions, and whatever values are chosen, they are applied to all countries, in a dynamic fashion that reflects the changing global economy. The report presents results for 12 representative countries and a selected set of illustrative “cases.” Each case begins with the selection of a reference mitigation pathway; this choice corresponds to a certain level of ambition and level of risk of exceeding 2°C. The mitigation pathway also implies an annual global mitigation effort, which drives society to diverge rapidly from business-as-usual emissions growth. Each country’s share of global responsibility and capacity determines its fair share of the global mitigation effort. In all of this, this report aims to provide input to the review of the Intended Nationally Determined Contributions (INDCs) that are now being tabled under the UNFCCC. It derives a defensible range for each country’s fair share of a given global climate effort. This provides a way to assess a given country’s position relative to the requirements of equity and science – that is, whether that country is a leader or a laggard