Operationalization of the distributive justice theory for subnational carbon budget allocation in the EU27. Subnational allocation of the global carbon budget (blue) is considered separately to derive regional production-based emissions budgets (yellow) and consumption-based emissions budgets (green). Production-based emissions budgets are further differentiated by main policy pillars: the EU Emissions Trading System (ETS) and the Effort Sharing Regulation. Credit: Nature Communications (2025). DOI: 10.1038/s41467-025-66802-9

Ten years ago, on 12 December 2015, the Paris Climate Agreement was signed at the UN Climate Conference. In order to limit global warming to well below two degrees, only a certain amount of CO2 may be emitted worldwide. While the focus was originally on national emission targets, more than 200 subnational regions and almost 300 cities have now adopted their own targets.

But how many emissions are they fairly entitled to? Researchers at the University of Graz have now developed transparent criteria for fair distribution at the subnational level for the first time and determined corresponding greenhouse gas budgets for all European regions. The paper appears in Nature Communications.

Do the emission targets set by regions and cities correspond to a fair distribution of the global greenhouse gas budget still available? Or are some perhaps claiming too much for themselves? A research group led by Karl Steininger, climate economist at the Wegener Center at the University of Graz, has developed a framework to calculate this.

Production- and consumption-based emissions

"We assume that every individual in a country has the same right to welfare benefits from emission-generating activities. We then distinguish between consumption- and production-based emission budgets," says Teresa Lackner, lead author of the publication, summarizing the basis for the new framework.

For CO2 caused by the domestic economy and industry, the scientists introduce the so-called Equal Transition Opportunity Production-Based Allocation (ETOPA).

"ETOPA is a mechanism for allocating production-based emissions fairly at the subnational level. It takes into account different regional economic structures and risks in the transition to a climate-neutral economy. After all, distributive justice in the greenhouse gas budget also means that all regions have equal opportunities," Steininger emphasizes.

Emissions associated with the consumption of a country’s population are largely not generated in the country itself; for example, when the components for a smartphone are produced on another continent. To be fair, however, they must also be taken into account.

"For the distribution of a national consumption-based emissions budget across regions, we propose a qualified, equal per capita allocation that takes into account regional basic needs, historical responsibility and advantages from previous emissions. This has not been sufficiently the case to date," says the climate economist.

As an example of ways to reduce consumption-based emissions, Steininger cites the revision of building regulations: "New requirements, such as the mandatory use of climate-neutral cement, could bring significant savings."

Research with and for practical application

The framework for the equitable distribution of the remaining greenhouse gas budget among the regions was developed and discussed with Austrian cities.

"Positive feedback, such as from the city administration of Linz, confirms that transparent, comprehensible criteria are helpful in arguing for emission reduction measures, also to counter accusations of greenwashing," reports Steininger.

In addition, the publication emphasizes that subnational effort-sharing is a political process and must be negotiated among national and subnational policymakers in participatory settings, including non-state actors such as industry, civil society and communities, to be feasible and gain public support.

More information: Teresa Lackner et al, Applying fairness in subnational carbon budget allocations, Nature Communications (2025). DOI: 10.1038/s41467-025-66802-9

Citation: A new framework addresses fair distribution of emissions (2025, December 10) retrieved 10 December 2025 from https://phys.org/news/2025-12-framework-fair-emissions.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.