Benefits and Pitfalls of an EU Emissions Budget Approach

Limitations of a budget approach

Global warming levels such as 2°C or 1.5°C can be translated into global budgets of cumulative CO₂ emissions, providing the volumes of carbon that can still be put into the atmosphere. The Intergovernmental Panel on Climate Change (IPCC) provides regular updates of such remaining carbon budgets to stay below selected temperature thresholds. Yet methodologies (and budget sizes) keep changing, while non-CO₂ emis­sions like methane or nitrous oxide are only indirectly accounted for. Moreover, questions about appropriate national (or EU-level) emissions budgets cannot be answered scientifically. The Paris Agreement sets a global long-term temperature goal, compliance with which requires col­lective global effort. Assigning a pre­cisely quantified national or European responsibility depends on assumptions that are not genuinely scientific but value-laden and political – and not provided by the IPCC. Closer examination of these dimensions cautions against deriving EU or Member State emissions budgets from the global level and trying to implement them as strictly ‘science-based’ limits that cannot be questioned by governments or parliaments.

No basis in Paris Agreement

The remaining carbon budget to meet a given temperature target with a given probability has a real physical limit and is therefore scarce. This necessarily implies a global distributional conflict over emission rights. If a remaining carbon budget were the basis of negotiations under the United Nations Framework Convention on Climate Change (UNFCCC), it would always result in a zero-sum game: What one country gets cannot be used by another. Not surprisingly, this approach has failed to gain traction in the UNFCCC.

Instead, the Paris Agreement follows a pledge and review approach, which is based on largely voluntary mitigation commit­ments (NDCs). These are to be strengthened by signatories every five years in a ratcheting-up mechanism. In the Global Stocktake, every five years the collective outcome of these national contributions is compared with the global emissions pathway deemed scientifically necessary. The first Global Stock­take will be concluded at the 28th Con­ference of the Parties (COP28) to the UNFCCC in late-2023 and will then initiate a new round of strengthened NDCs that will need to be submitted by 2025. In set­ting mitigation targets, the guiding UNFCCC principle of common but differen­tiated respon­sibilities and respective capabilities (CBDR-RC) applies. While this principle was never quantified under the UNFCCC, the Paris Agree­ment explicitly mentions that devel­oped countries should “continue taking the lead” in reducing emissions.

Multiple possible allocation principles

The allocation of the EU’s precisely quan­tified responsibility depends on several assumptions. The question of what the EU’s fair contribution to achieving the global long-term temperature goal should look like cannot be answered unambiguously since it depends very much on the equity and fairness criteria applied in such calcu­lations. In the scientific literature, these span from a mere per capita approach (usually favouring developed countries) to the full inclusion of historical emissions (favouring developing countries). Consider­ing the historical responsibility of early industrialized countries for climate change (i.e. choosing a starting date of 1750 or 1850) would usually leave no allowances for the EU in a 1.5°C-compatible emissions budget. Furthermore, a comprehensive equity approach would also need to factor in the respective national mitigation poten­tials and costs, as well as the macro­eco­nomic situation of all countries.

Varying methodologies and volumes

Contrary to widespread perceptions among climate policymakers and the media, global carbon budgets do not provide a sufficiently stable starting point. Translating the Paris Agreement’s long-term temperature goal (“holding the increase in the global average temperature to well below 2°C above pre­industrial levels and pursuing efforts to limit the temperature increase to 1.5°C”) into carbon budgets already involves genu­inely political decisions, be it about the ‘ap­propriate’ warming level (1.5°C, 1.75°C, or 2°C) or the sufficient likelihood of target achieve­ment (50 per cent, 67 per cent, or 83 per cent). Furthermore, the remaining carbon budgets deter­mined by the IPCC change over time due to scientific advance­ments. The remaining carbon budgets pro­vided in the IPCC’s 5th Synthesis Report (2014) were significantly increased in the Special Report on 1.5°C (2018) and were then again revised slightly upwards in the fol­low­ing IPCC Working Group I Report (2021), especially for a 67 per cent likelihood. If a CO₂ budget for the EU were directly linked to the IPCC’s calculations, this would in­evitably amount to significant (upward or downward) adjustments after every major IPCC report. Strictly deriving the EU’s re­main­ing CO₂ budget from the IPCC’s global carbon budget is therefore not a suitable approach to creating a reliable policy tra­jec­tory. Furthermore, and often over­looked, there is no global GHG emis­sions budget. For methodological reasons, the IPCC budg­ets cover only CO₂ (as it accu­mulates in the atmosphere) while EU cli­mate policy covers all major greenhouse gases, including nitrous oxide and short-lived climate forcers like methane. In miti­gation pathways, achiev­ing net-zero GHGs is more ambitious (and occurs later) than net-zero CO₂, because remaining non-CO₂ emissions (largely from agriculture) need to be counterbalanced by CO₂ removal. While achieving net-zero CO₂ emissions globally would likely lead to tem­perature stabilization, reaching and sustain­ing net-zero GHG emis­sions globally would – under the emis­sions metrics used in the UNFCCC and in the EU – lead to a slight temperature decrease.

Cumulating instead of budgeting

While the global CO₂ budget can be deter­mined in principle under the given uncer­tainties and while it is a useful concept in representing the urgency of the global cli­mate problem, simply breaking down the global CO₂ budget by individual entity (budget­ing) and trying to create strict ‘sci­ence-based’ budgets is not a suitable ap­proach for the climate policy of the EU and its Mem­ber States. However, cumulating (i.e. converting planned European or national mitigation pathways into indicative pro­jected total CO₂ or GHG emissions over several years or decades) can be a viable way of representing EU or Member State ambition levels. When compared to the prevalent fixation on distant annual targets that is often found in European climate policy, the approach of cumulating emis­sions has two major advantages that are often cited by proponents of strictly derived emissions budgets. First, cumulating allows for better comparability of different pro­posed pathways leading to the same target year for CO₂ or GHG emissions neutrality, thereby shifting the focus from the target year itself to the overall level of ambition. This allows for a better comparison of dif­ferent political entities (such as the Euro­pean Union and the United States) in terms of their climate action ambitions. Second, this approach still allows for proposed trajectories at EU and Member State levels to be compared with what would be neces­sary under different global equity criteria.

The cumulative approach would make it not only possible to assess a country’s level of ambition but also to quantify what addi­tional international obligations would fol­low from this, for example, in helping to establish a low-carbon economy in devel­oping countries, which is a goal of the Just Energy Transition Partnerships (JETPs). Even though the Paris Agreement follows a pledge and review approach, there is a national responsibility to make an appro­priate con­tribution to global climate change mitigation, which should be ori­ented towards the highest possible ambi­tion (Paris Agreement, Art. 4, para. 3).

The independent ESABCC advisory board has taken an approach in line with these considerations, recommending a range and not a single number for the EU’s emissions budget. The range considers multiple dimen­sions of fairness and feasibility. The ESABCC’s advice is based on the physical limits of the global budget, while the EU’s ‘fair share’ is derived assuming different allocation schemes. In addition, the advi­sory board gives a range for the cumulative EU budget based on different pathways for a net-zero GHG trajectory. The ESABCC con­cludes that a fair contribution to climate change mitigation requires ambitious reduc­tions in domestic emissions, complemented by measures outside the EU.

Focus on climate governance instead of an emissions budget

Given the problems that arise from rigidly deriving domestic emissions budgets from global carbon budgets, it is more appropriate to take the already existent policy in­stru­ments and trajectories as a starting point. Since these are already established policies and plans, they are much more important in governing the transition towards net-zero GHG emissions by 2050 than any budget calculation. These policy instruments set specific targets, including those established in the Directives on the Emissions Trading Systems (ETS I and II), under the Effort Sharing Regulation on sectors beyond the ETS, and under the Regu­lation on Land Use, Land-Use Change, and Forestry (LULUCF). Targets and long-term trajectories have recently been revised under the ‘Fit-for-55’ legislative package and will be revised once again in the second half of the 2020s for the time period be­tween 2031 and 2040. In some cases, a con­crete year for a revision is already set.

A key dimension of these revisions will be how instruments are linked and incre­mentally integrated. A yet unanswered ques­tion concerning the governance archi­tecture is how and where carbon removal that counterbalances residual emissions will be addressed. This facet of EU climate policy is likely to play a strategic role in future efforts to combine currently separate instruments and policy pillars. Member States’ National Energy and Climate Plans (NECPs) to be submitted by mid-2024 will provide key information in this respect. The national targets and modelling efforts to be documented in the 27 NECPs will help to explore emerging preferences and coali­tions that will shape the next phase of the EU’s climate policy. For more robust EU cli­mate governance, a more systematic ap­proach that allows for mutual learning from implementation experience across Member States and sectors is needed, for example through more frequent mandatory evalu­ation and peer review, including the allo­cation of public finance for climate action.

To summarise, the political debate on the design of EU climate policy after 2030 should not focus primarily on the ‘appropriate’ target level for 2040 as long as it is ambitious enough to realise net-zero GHG emissions by 2050. Rather, European cli­mate policymakers in the Council, Parlia­ment, and Commission should prioritise further developing the governance archi­tecture, strengthening policy instruments, and bolstering public support for what is likely to become the most challenging phase of EU climate policy yet.