How do we fight climate change in a way that is fair for all?

In a world characterised by disparities in resources, historical greenhouse gas emissions and financial capabilities, how can countries across the world agree on a fair contribution in reducing climate change?

By Faculty of Science Masters students Jack Simkin, Maddison Brian, Michael Traeger and Raveena Grace, with Yann Robiou Du Pont

Equity has been a major argument affecting international ambition on climate mitigation and therefore national policies. University of Melbourne PhD candidate Yann Robiou du Pont from the Australian-German Climate College has created a model to provide guidance on equitable solutions to help reduce climate change.

Translation: The Paris Accord - It is done! Picture: U.S. Department of State from United States [Public domain], via Wikimedia Commons

The First Step

In November 2016, the Paris Agreement came into force. With 195 Parties signing, and 166 ratifying, the participating countries of the Paris Agreement contribute to over 85 percent of total global greenhouse gas emissions.

It is the first international commitment to limit global warming to well below 2 degrees above pre-industrial levels with efforts to pursue 1.5 degrees, aiming for net zero emissions by 2050.

Reports have suggested that peak emissions have stalled, however current policies are projected to result in a temperature increase of approximately 3.3°C by2100, presenting major risks, sometimes existential, for many countries.

Under the Paris Agreement, signatories are required to submit Nationally Determined Contributions (NDCs) outlining emission reduction and adaptation plans. As part of the ‘ratcheting up’ process, NDCs are submitted every 5 years to reflect increasing ambition of emissions mitigation targets, and include information on how national pledges are fair and ambitious.

But this wording raises questions about what is ‘fair’ and what is ‘ambitious’?

Picture: Young Friends of the Earth Europe, Flickr

What is equitable?

Robiou du Pont is working to resolve this ambiguity. “The overarching question in my thesis is trying to see how you can proceed (in meeting the Paris Agreement targets) even when different countries have different visions of equity.”

The issue of defining equity on the global scale is not new. In 2013, the Fifth Assessment Report to the Intergovernmental Panel on Climate Change outlined multiple visions of equity in relation to climate action transformation pathways.

In his research, Robiou du Pont used five of these Intergovernmental Panel on Climate Change visions:

Research categories

IPCC Categories


Equal Cumulative Per Capita

Equal Cumulative Per Capita

Populations with high historical emissions, have low emission allocations



Countries with high GDP per capita have low emission allocations and take on more financial burden in reducing emissions.

Equal per capita


All countries converge to the same annual emissions per capita by 2040

Greenhouse Development Rights



Ensures wealthier countries, or countries with higher historical emissions take on more responsibility, preserving an underdeveloped country's right to pursue development.

Constant emissions ratio

Staged approaches

A differentiated approach at different times for different countries

“The issue with multiple visions of equity is that even if every country does what is fair according to one vision of fairness, it is unlikely to be sufficient to achieve the Paris Agreement” says Robiou Du Pont. “Indeed, countries tend to favour visions of equity that requires the least stringent effort on their behalf.”

Compounding the issue are inherent uncertainties in both climate modelling and defining climate equity.

Existing research shows current cumulative NDC pledges are insufficient to achieve the 2-degree target set out in the Paris Agreement.

A model for equity

“Determining which country is ambitious and which one is not requires a metric based on equity.” says Robiou Du Pont.

By comparing individual NDCs against the five visions of equity, Robiou du Pont has provided a user-friendly quantitative guide to check the equity approaches that each country follows. It aims to add an element of transparency for policy makers and the public following negotiations on national emissions targets.

The multi-equity model also has the potential to be used in legal cases. In 2015, a lawsuit was filed against the Dutch government, claiming they had taken insufficient action on climate change, endangering current and future citizens. The court ruled that the Dutch government should reduce emissions more than their existing pledge for 2020. So far, there have been nearly 900 similar citizen-led cases globally against national Governments taking insufficient climate action.

“The model shows that some of these NDCs don't even align with any vision of equity, but at least having all countries aligning with one, or with the equity concept they supported would already be an improvement” says Robiou du Pont.

A Country’s Plan

Robiou Du Pont’s model shows China’s NDC does not align with any Intergovernmental Panel for Climate Change category of equity.

“Some countries might overachieve their NDC even under business as usual trajectories because they didn't want to commit too much before the Paris Agreement” says Robiou du Pont.

“It could be the case that China, whose NDC doesn't align with any vision of equity, over delivers. And that could be a negotiation strategy - going cautiously.”

However, Germany follows a different approach, adopting the Intergovernmental Panel for Climate Change recommendation for developed countries; a 40% reduction of 1990 emissions by 2020 before planning how to achieve this target.

Meeting these quantifications of equity could inform the ratcheting up mechanism of the Agreement.

“A incremental process could see countries aligning their pledge with at least one vision of equity as a first step” Robiou Du Pont.

“As a second step, countries could align their pledge with at least two equity concepts and continue this ratchet up until the world in on track to achieve the Paris Agreement.”

Australia’s contribution

Australia’s NDC aims to achieve a 26% reduction of 2005 emissions by 2030. According to Robiou du Pont’s research, this target meets two visions of equity in meeting the 2 degree objective of the Paris Agreement. In a 1.5 degree simulation, the Australian NDC fails to meet any vision of equity.

Australian NDC compared to the five visions of equity in line with limiting global warming to 2 degrees. The black circle represents Australia’s NDC, and the shaded stars represent the visions of equity met. Picture:

The two visions of equity that Australia meets are highly contentious. The Constant Emissions Ratio relies on a grandfathering approach, in which new rules are applied to all future cases, but do not affect current situations. However, this approach is not generally supported by any party as an equitable approach in climate justice.

The Greenhouse Development Rights approach, proposed to support developing countries’ ‘right to development’, ranks Australia particularly high. This approach is contentious because ‘business as usual projections are challenging to agree on, as it is difficult to know what current emissions should be if no actions were taken.

Australia’s emission reduction targets have been criticised by international organisations, with the Australian Government’s own Climate Change Authority recommending stronger climate action.

So what comes next?

Robiou du Pont is looking at a potential ‘unifying’ combination of multiple concepts of equity, with the aim of offering an alternative to the current deadlock of negotiations on effort-sharing. Providing a single definition allows Governments to focus on determining an appropriate, consistent pathway to 2 degrees, or 1.5-degree ambition.

A unifying vision of equity would help to judge the ambitions of all countries on a single scale, and circumvent an utopic agreement on what constitutes a fair contribution.

As Robiou du Pont points out, “This discussion is always going. Ultimately all countries agreed to go to 2 degrees. They know that we're not there at all. That progress (on climate action) should be made all the time.”

More Information

Julia Cleghorn