In combatting climate change and environmental degradation, the budget is one of the most powerful tools that subnational governments have at their disposal. The budget is the financial expression of the implementation of responsibilities as well as the result of political choices. The process of budgeting is a complex system that requires compliance with standards and norms, to deal with financial constraints (over which local authorities do not always have leeway) and to make political trade-offs. It is during the process of drafting and voting on the budget that a region or municipality has the possibility to measure its financial commitments to the environment, to establish and resource green priorities to integrate green concerns into all budgetary processes and decisions, or put another way, to align current and capital expenditure and revenue with environmental and climate objectives. When this process is combined with other means of action, such as regulatory action, or environmental and land-use planning, it lays the foundation for future climate and environmental action by all territorial stakeholders. Integrating environmental and climate concerns fully into the budgetary process effectively complements the range of environment and climate tools available at the subnational level. The opportunity that green budgeting offers subnational governments to make full use of their budget to achieve their green objectives provides a strong rationale for them to implement such an exercise.
Adopting a green budgeting approach presents many benefits for subnational governments, with the most salient among these being that it is a concrete, practical tool that subnational governments can use to align their expenditure and revenues with their green objectives and mainstream climate and environmental considerations throughout their budgetary decision-making processes.
Initiating a green budgeting approach fosters “cross-functional approaches” within a subnational government by bringing financial, climate, and environmental issues closer together. This reduces siloed thinking about climate and the environment as being only the responsibility of the Department of Environment and helps to incite a whole-of-government approach to meeting green objectives. Likewise, green budgetary processes can help regions and cities to take careful account of the potential impact of action in one area to spill over into other policy domains and help to identify needed accompanying decisions by social and territorial measures (OECD, 2020[10]).
Adopting a green budgeting approach helps to instil a science-based understanding of environment and climate change issues across the administration and among elected officials, making apparent the importance of integrating climate and environmental considerations into budgetary decisions. Green budgeting facilitates and improves the rationality of decisions that can be made on the basis of scientific assumptions, data and indicators which therefore sheds light on political trade-offs, in an area where there are often numerous unfounded beliefs, symbolism and presumptions.
The green budgeting process also contributes to improving the evaluation of public policies. It can assist in the re-design of objectives, timelines and means to achieve these objectives. It thus brings actions in line with intentions.
Green budgeting is complementary and symbiotic to other priority budgeting exercises, such as gender, SDG, or pro-poor budgeting. These priority areas are all cross-cutting and interdependent and budgeting for them relies on similar internal operational procedures such that a priority budgeting exercise in one area can enable and strengthen another.
Adopting a green budgeting approach helps subnational governments to prioritise and select low-carbon and resilient investment and spending. This is made all the more important in the context of the post-pandemic green recovery and the unprecedented influx of resources for “green” investment at the subnational level. Green budgeting tools such as green budget tagging, climate/environmental impact assessments, and climate/environmental cost-benefit analyses can help decision-makers to make informed decisions on where to spend and invest today to prevent carbon lock-in.
Relatedly, green budgeting improves the identification of funding gaps associated with achieving their green objectives and helps subnational governments to mobilise additional sources of public and private finance to bridge these gaps. Green budget tagging, for example, can be used to select expenditure items to be funded using green bonds and green loans as has been done by regional governments in Germany (Hessen and North Rhine-Westphalia) or Spain (Andalusia).
As an ever-growing number of regions and cities set ambitious climate and environmental targets, it is increasingly important that they consistently and transparently communicate to their citizens, stakeholders, and partners on the progress being made to reach these targets. Using green budgeting, subnational governments can communicate how much they are spending and investing related to climate and the environment, the impact of this expenditure on territorial progress to meeting green targets, and the overall coherency of the government’s fiscal and budgetary policy with their stated green objectives. This transparency on the use of public funds helps to hold governments accountable to their citizens and stakeholders and can contribute to restoring trust in government, a key factor for ensuring the success of the carbon-neutral transition. It thus promotes the emergence of or reinforces the dialogue between, environmental, economic and social actors, that did not always exist while these issues appear to be often interdependent.
It is important to note, however, that green budgeting is a means to an end, not an end in itself. Green budgeting will not ensure the green transition; however, it can help to achieve the transition’s goals. Put plainly, green budgeting is not a silver bullet. It is one of several tools that subnational governments have at their disposal for the green transition together with other instruments, such as regulatory policies, public procurement or environmental and land-use planning tools. Green budgeting is most effective when it is used in combination and co‑ordination with these other government instruments and actions.