Flawed carbon accounting lets major polluters delay action, study finds

# Flawed carbon accounting lets major polluters delay action, study finds

*A new fairness test says big emitters owe faster cuts—and courts are starting to agree.*

Researchers at Utrecht University say common ‘fair‑share’ assessments for national climate pledges have a built‑in bias that favours high emitters. Published on 3 September 2025 in Nature Communications, the study proposes a method rooted in historical responsibility and capacity that demands steeper cuts by wealthy countries and more finance for poorer ones. The authors say the shift could shape court rulings on whether climate targets are fair and ambitious.

## What’s wrong with the current maths
Many assessments start from today’s higher emissions, moving the goalposts and letting heavy emitters claim they are on track. The researchers say this approach shifts the burden to countries that contributed least: “previous studies assessing countries climate ambition share a feature that rewards high emitters at the expense of the most vulnerable ones.”

## A new way to share the carbon budget
The team proposes calculating each country’s immediate ‘ambition gap’ using historical responsibility and capability. That would trigger rapid cuts in wealthy, high‑emitting nations and require substantial finance for extra mitigation in lower‑income countries.

## Who needs to do more
Under the new approach, high‑emitting countries—including the G7, Russia and China—must raise ambition. Among high‑income countries, the largest gaps are in the United States, Australia, Canada, the UAE and Saudi Arabia.

## Courts are becoming climate referees
Fair‑share studies now inform climate cases. The European Court of Human Rights recognised that weak national action can breach human rights, and the International Court of Justice affirmed a duty to prevent significant climate harm. “This strengthens and underscores the growing role of courts in enforcing climate justice,” says lead author Yann Robiou du Pont.

### The takeaway
Resetting carbon maths to reflect responsibility and capacity could speed cuts where they matter most—and help courts hold countries to their fair share.

Read the full study summary on ScienceDaily: [The flawed carbon math that lets major polluters off the hook](https://www.sciencedaily.com/releases/2025/09/250903075156.htm).