The way residual or unavoidable emissions are currently defined and dealt with misses an important dimension: fairness.

Oxfam recently published its ‘Carbon inequality kills’ report, which exposed the cataclysmic climate responsibility of the world’s richest. The remaining global carbon budget would be exhausted in under five months if everyone emitted at the same rate as the wealthiest 1% by income.

Flagrant inequalities such as these are particularly relevant in our present political climate, where the topic of residual emissions – i.e. the “unavoidable” emissions that remain after decarbonisation has run its course – is receiving increased attention. With definitions and clear pathways missing, there is a risk that we end up in a situation where residual emissions are defined by the powerful and wealthy, thereby intensifying existing inequalities. Consequently, value judgements on what counts as residual and the implications of labelling anything as such must be considered.

Residual omissions

To date, EU legislation has made scant reference to the topic. The Delegated Act on sustainability reporting standards briefly states that residual emissions would occur: “after approximately 90-95% of GHG emission reduction [is achieved]”, yet caveats this by allowing for “justified sectoral variations in line with a recognised sectoral decarbonisation pathway”. 

Further, in its proposed 2040 target, the European Commission only provides an implicit residual emissions target of less than 850 megatonnes of carbon dioxide equivalent, excluding emissions from the land-based sector. These emissions would need to be counterbalanced by removing 400 million tonnes of CO2, yet at present, less than 0.6 million tonnes of carbon is permanently removed per year. The projected emissions target is therefore considerably higher than what we can afford.

At the national level, definitions vary: Switzerland and Norway describe residual emissions as those that cannot be completely eliminated, whilst Iceland refers to “those that are unlikely to be eliminated”. Meanwhile, France adopts a more nuanced approach, describing them as “unavoidable according to the current state of knowledge”, with the expectation that technological development could alter its scope. 

Overall, definitions on residual emissions remain unclear, and fail to factor in social justice concerns, including the right of society to collectively choose which emissions are vital and which we can live without.

Taking matters further, a study led by Harry Smith of the Tyndall Centre for Climate Change Research, looked into 71 long-term national climate strategies. It concluded that residual emissions average 21% of peak emissions for industrialised and developed countries by mid-century. 

Similarly, a study led by Holly Buck from University at Buffalo found that, in 2050, these same countries expect their residual emissions to stand at around 2.2 gigatonnes per year, representing around 18% of their current emissions levels. According to the authors, should the rest of the world follow a similar trajectory, the resulting residual emissions in 2050 would be over 12 gigatonnes per year (if weighted by current emissions). This is far too high to curb planetary heating and far outstrip current and likely future permanent carbon removals capacity. 

Licence to emit

The Intergovernmental Panel on Climate Change (IPCC) has stated that the deployment of carbon removals to counterbalance hard-to-abate emissions is unavoidable if we are to achieve net zero emissions and remove more than we emit thereafter. Given that the amount of emissions left should be matched with permanent removals capacity, how residual emissions are defined also has implications for the extent to which these technologies will be used and how realistic such future deployment would be.

If deployed in a manner that respects planetary boundaries, all removal options are constrained by real-world limitations. These limits to scalability can include, energy,  biomass, land, raw materials, fresh water, and finance. Removals also face numerous trade-offs. For instance, direct air capture and storage (DACCS) needs renewable energy to be sustainable. Yet using renewable energy for DACCS takes away from other uses, such as electrifying transport and industry, or from powering schools or hospitals. In addition, over-reliance on carbon removals could act as a licence to emit and deter polluters from pursuing feasible decarbonisation pathways.

A question of fairness

In light of the challenges associated with the large-scale deployment of carbon removals, it is important to keep the volume of residual emissions as low as possible. But then again, how do we define these in a way that is good for the environment and for society as a whole? 

When selecting which emissions count as residual, it is important to ask who benefits, whose interests are being served, and how fair the distribution of the burden is? Is it to the benefit of all or a select few? And why are such emissions considered impossible to abate in the first place? For the sake of fairness, we must avoid a situation where what is classified as residual perpetuates or deepens social inequalities.

To illustrate this point, aviation is frequently labelled a hard-to-abate sector. While technologies are not currently commercially available to power planes without significant greenhouse gas emissions, this does not mean all aviation emissions are hard-to-abate – it is also a question of sufficiency. 

It is estimated that 1% of the world’s population accounts for 50% of commercial aviation emissions. Treating these emissions as “residual” serves those rich and privileged enough to be able to fly frequently and the business-as-usual status quo in the sector.  The issue becomes more acute considering the variety of measures that could be taken to reduce aviation emissions, such as increasing prices for frequent flyers, restrictions on short-haul flight, and imposing bans on private jets. In this vein, the argument that aviation emissions count as residual becomes untenable, even more so if they are to be counterbalanced by carbon removals, a resource with finite capacity.

Similarly, for agriculture, the sector is responsible for 11% of the EU’s total net greenhouse gas emissions, of which two-thirds stem from livestock. In this case, qualifying the agricultural sector as a whole as residual can be viewed as a means to safeguard the interests of Big Meat and Dairy or of affluent populations who consume quantities of meat that far exceed dietary requirements. But here too emissions reductions are possible: demand-side policies can be adopted by radically shifting consumption patterns, sustainable food frameworks promoted, and overall livestock numbers slashed.

Social justice concerns also emerge when looking at the North-South divide. If wealthy countries decide to use their limited carbon removals capacity to balance out mislabeled “residual” emissions from activities where emissions or activity can actually be reduced, this will shift the pressure to cut actual emissions to those least responsible for them. Similarly, if wealthy countries decide to opt for unsustainable CDR methods, such as forestry-based bioenergy with carbon capture and storage, companies and governments would have to rely on the Global South to provide the land and biomass needed for this technology. This risks entrenching neocolonial practices, as land is rendered more attractive, ultimately resulting in land grabbing (on top of ecosystem and biodiversity concerns).

The above represents just a few considerations of what is at play when assessing what should count as residual. Climate change disproportionately impacts the most vulnerable. Meanwhile, some privileged groups with vested interests insist that their emissions are unavoidable. 

We must be aware of the power dynamics at play and adopt a social justice perspective when deciding which emissions are vital to society. It is high time for a societal and political debate on the matter, rather than ignoring this key issue. This will allow what is truly residual to be earmarked for those most affected by climate change and consequently those least responsible for historical emissions.