2.1. Background
The 21st Conference of the Parties (COP21) to the United Nations Framework Convention on Climate Change (UNFCCC), held in Paris, marked a turning point in global climate governance. During this event, the Paris Agreement was adopted—an international treaty that established ambitious goals to strengthen the global response to the threat of climate change and enhance countries’ resilience to its impacts.
The Paris Agreement aims to reduce GHG emissions within the context of sustainable development. Its central objective is to limit the increase in global average temperature to well below 2 °C above pre-industrial levels, with additional efforts to restrict the rise to 1.5 °C. These targets reflect the scientific consensus on the urgent need to mitigate climate change and avoid irreversible impacts on ecosystems and human populations [
5].
To achieve its proposed goals, the Agreement introduced the concept of Nationally Determined Contributions (NDCs), which are the voluntary commitments made by each country to reduce GHG emissions, considering their socioeconomic conditions and local capacities. These commitments are periodically reviewed, allowing progressive adjustments to increase their ambition over time.
In Brazil’s case, its NDC sets absolute reduction targets for GHG emissions by 48.4%, or 1.24 GtCO
2e, compared to 2005 levels by 2025, and an indicative target of 53.1%, or 1.36 GtCO
2e, by 2030. The country has also committed to achieving climate neutrality, or net-zero emissions, by 2050 [
6]. These targets reflect the country’s commitment to aligning its economic development with the decarbonization of its economy, fostering technological transitions and advances in climate policies [
7].
Monitoring and transparency in the fulfillment of NDCs rely on reliable emissions data, which are collected and organized through emissions inventories. The emissions inventory is a fundamental tool for the formulation and tracking of NDCs, as it provides a detailed analysis of GHG sources and sinks within a specific territory. These inventories allow the identification of priority sectors for emissions reduction and the tracking of progress over time. However, to be effective, inventories must adhere to robust and internationally recognized methodological standards, such as the GHG Protocol [
8].
The GHG Protocol is one of the most widely used frameworks for the calculation and reporting of GHG emissions. It provides guidelines that can be applied by governments, businesses, and other organizations, ensuring consistency, transparency, and comparability of data. In the context of NDCs, the GHG Protocol helps standardize accounting methodologies, enabling countries to demonstrate compliance clearly and reliably with their reduction targets. Furthermore, it fosters harmonization between national inventories and corporate efforts to measure and reduce emissions, strengthening the synergy between public policies and private initiatives.
The GHG Protocol categorizes emissions into three distinct scopes, providing a comprehensive view of GHG emission sources. Scope 1 covers direct emissions from sources controlled by the organization, such as industrial processes, fuel combustion in boilers, or company-owned vehicles. Scope 2 includes indirect emissions related to purchased energy, such as electricity, steam, or heat generated by third parties and consumed by the organization. Scope 3 emissions encompass indirect emissions across the entire value chain of an organization and are divided into 15 categories, including those related to purchased goods and services, business travel, product transportation, and the use of sold products. These emissions also include impacts from waste disposal, capital goods production, leased assets, and the end-of-life treatment of sold products. By considering these various categories, companies can identify and mitigate emissions throughout their supply chain and operations, providing a more comprehensive view of their environmental impact.
Category 3 of Scope 3 emissions, which focuses on fuel- and energy-related activities (not included in Scope 1 or Scope 2), refers to emissions arising from the production and transportation of fuels and energy that an organization purchases. These emissions are indirect, as they occur outside the organization’s direct operations but are still a result of its energy consumption. Specifically, 3D, which addresses emissions from upstream energy generation and transmission, covers the emissions produced in the process of generating and transmitting the energy that the organization purchases but that are not captured in Scope 1 or Scope 2. This category helps organizations understand the broader environmental impact of their energy consumption by accounting for emissions from energy production and transmission that occur before the energy reaches the organization’s facilities or operations. Reducing these emissions often involves working with suppliers to choose cleaner energy sources or improving energy efficiency throughout the supply chain.
The SBTi was established to address the critical challenge of aligning corporate emissions reductions with global climate objectives. It is a collaboration between the Carbon Disclosure Project (CDP), the United Nations Global Compact, the World Resources Institute (WRI), and the World Wide Fund for Nature (WWF). The SBTi provides a standardized framework for developing and validating SBTs in the corporate sector, translating the Paris Agreement’s goals into actionable strategies for companies across diverse industries. Its methodology has become the leading global standard for corporate climate action. Additionally, the SBTi has created a sector-specific guide tailored to the unique characteristics and challenges of the power sector, cementing its role in advancing industry-specific climate strategies.
The urgency of transformative climate action was underscored by the IPCC in its Special Report on Global Warming of 1.5 °C, which highlighted the need for rapid and unprecedented societal changes to limit global warming. To maintain a 66% probability of limiting warming to 2 °C, the IPCC sets a maximum cumulative anthropogenic emissions budget of 3670 GtCO2, reduced to 2900 GtCO2 when accounting for other greenhouse gases. By 2011, approximately 1890 GtCO2 had already been emitted, leaving only 1010 GtCO2 available from that point onward.
The IPCC’s Fifth Assessment Report (AR5) defined four Representative Concentration Pathways (RCPs), corresponding to approximate radiative forcings of 2.6 W/m2, 4.5 W/m2, 6 W/m2, and 8.5 W/m2. These RCPs, spanning 1850–2100, represent different climate policy scenarios. Among them, RCP 2.6 is the most ambitious, aiming to stabilize greenhouse gas concentrations below 450 ppm CO2e. This pathway requires cumulative emissions of 990 GtCO2 by 2100 and aligns with the goal of limiting warming to 2 °C. Achieving this scenario necessitates drastic emission reductions, reaching net-zero emissions in the second half of the century, supported by advanced technologies such as carbon capture and storage (CCS) to offset residual emissions.
In response, the SBTi has introduced technical resources to help companies establish GHG reduction targets aligned with a 1.5 °C warming threshold. For the power sector, the SBTi has endorsed specific 1.5 °C-aligned pathways, providing clear guidance for setting emissions reduction targets that demonstrate climate leadership. The SBTi primarily draws scenarios from the Integrated Assessment Modeling Consortium (IAMC), which compiles over 400 peer-reviewed emission trajectories evaluated in the IPCC Special Report on Global Warming of 1.5 °C (SR15). These scenarios must meet stringent criteria, ensuring they are plausible, consistent, and aligned with global climate goals.
In the initial classification, scenarios are assessed using temperature limits and probabilities based on the reduced-complexity climate model MAGICC6, adopted by the IPCC in SR15 [
5]. This evaluation considers projected warming by 2100 and prior warming peaks. Scenarios aligned with the Paris Agreement aim to keep warming “well below 2 °C” (66% probability) or limit the increase to 1.5 °C (50% probability), including trajectories with little or no overshoot. Scenarios failing to meet the Paris Agreement’s urgency, such as those projecting emission peaks before 2020 or after 2025, are excluded. These pathways also exclude those relying excessively on speculative CO
2 removal (CDR) technologies due to their associated risks and uncertainties. This refinement process narrows an initial set of 177 scenarios to 20 that are consistent with the 1.5 °C target. These trajectories serve as a foundation for SBTi methodologies, such as the Absolute Contraction and Sectoral Decarbonization Approach, providing robust pathways for corporate climate action.
2.2. Decarbonization of the Power Sector
The deep decarbonization of the power sector is a cornerstone of all climate scenarios that limit global warming to 1.5 °C. Achieving these scenarios requires sector emissions to decrease by 70–92% between 2020 and 2035 and to approach net zero by 2040–2045. This sharp reduction is driven by rapid cost declines in solar, wind, and energy storage technologies [
9], supported by favorable policy frameworks and increasing demand for renewable energy [
9]. The share of electricity in final energy consumption is also projected to rise steadily through 2050, further underscoring the power sector’s critical role in global decarbonization efforts. Accordingly, SBTi pathways aligned with the 1.5 °C mandate significant near-term emission reductions (2020–2035) and the achievement of near net-zero emissions by 2040.
Currently, the SBTi recommends two methods for setting Scope 1 and 2 emission targets. The first one is the Absolute Contraction Approach (ACA), which requires all companies to reduce their absolute emissions by the same proportion. This target is expressed in terms of total metric tons of CO2 equivalent (tCO2e), ensuring a standardized approach to measuring and reducing greenhouse gas emissions. Under this framework, all companies, regardless of their sector, are required to achieve the same percentage reduction in emissions. In the medium term, companies are expected to reduce their emissions by 4.2% annually, which equates to a 42% reduction over a decade. In the long term, the target is even more ambitious, requiring a 90% reduction in emissions. This approach aims to drive substantial and consistent progress toward global decarbonization goals across all industries.
The second one is the Sectoral Decarbonization Approach (SDA), a method designed to guide companies in setting science-based emissions intensity reduction targets [
10]. The SDA method aligns corporate carbon intensity pathways with sector-specific decarbonization scenarios derived from global climate mitigation strategies. The SDA allows companies to set targets that account for both projected activity growth and initial carbon performance.
A sector-specific target for the energy sector is expressed in terms of metric tons of CO2 equivalent per megawatt-hour (tCO2e/MWh), reflecting the unique characteristics and requirements of the sector. Unlike absolute targets that apply uniformly across all industries, the percentage reduction in emissions varies between companies within a sector, depending on their starting points and expected growth rates. In the medium term, companies are expected to achieve significant emissions reductions, ranging from 70% to 92%. Looking ahead to the long term, the goal is to reach a near-zero emissions intensity of 0.0092 tCO2e/MWh. This tailored approach aims to align the energy sector with broader global climate goals while accounting for the sector’s specific operational realities.
Although the ACA was previously applicable to targets aligned with 2 °C, companies must now set targets compatible with a well-below 2 °C scenario or the more ambitious 1.5 °C scenario. ACA is broadly applicable, while SDA is used for certain “homogeneous” sectors and currently only calculates targets aligned with 1.5 °C for the energy sector. For certain sectors, the SBTi allows or requires the use of specific methods for target setting, including some variants of ACA and SDA (e.g., for aviation) and other distinct methods (e.g., for financial institutions). Dedicated methods and guidelines for other sectors are still under development.
For Scope 3 emissions, the SBTi’s requirements are less stringent, acknowledging that companies have less ability to quantify and influence these emissions. Companies must set science-based targets for Scope 3 if these emissions represent at least 40% of the total Scope 1, 2, and 3 emissions, and the targets must cover at least two-thirds of Scope 3 emissions. Companies can use methods other than ACA and SDA, with Scope 3 targets still aligned with a 2 °C scenario, as well as the well-below 2 °C or 1.5 °C scenarios. Alternatively, companies may set supplier or customer engagement targets to encourage them to set their science-based targets for their Scope 1 and 2 emissions.
For Scope 2, SBTi also allows for setting targets to increase the procurement of renewable electricity, and Scope 3 engagement targets involve directing a percentage of suppliers and customers (based on Scope 3 emissions or procurement spend) to adopt science-based targets.
2.3. Literature Review of Science-Based Targets Methods
The literature points out various limitations and challenges in implementing SBTs. While the adoption of SBTs is voluntary and should not replace more ambitious climate policies, it remains unclear whether they help or hinder the adoption of the policies necessary to align with the Paris Agreement.
Bjørn [
11] identifies a problem with how renewable energy certificates (RECs) are used by companies to report Scope 2 emission reductions as part of their SBT efforts. While current emission accounting standards allow companies to use RECs for progress on purchased electricity emissions reductions, previous analyses suggest that this practice may not lead to additional renewable energy production. This could result in an overestimation of mitigation effectiveness, as Scope 2 emission trajectories from 2015 to 2019, when excluding REC benefits, are not aligned with the 1.5 °C target and barely meet the Paris Agreement’s “well below 2 °C” goal [
12].
Walenta [
13] explores the potential of corporate climate action tools like risk assessments and SBTs but raises concerns about their effectiveness and potential manipulation. SBT adoption, while promising, raises doubts about its ability to stabilize the climate, especially given disparities in wealth accumulation and emission reduction burdens. Faria and Labutong [
14] highlighted issues with the SBT’s use of “grandfathering”, which allocates emission quotas based on historical data, potentially perpetuating global inequalities. Additionally, emission reduction trajectories often assume continuous growth in energy and materials, with heavy reliance on large-scale carbon removal, overlooking alternative scenarios with more sustainable futures and less environmental impact [
12].
Various methods exist for establishing science-based targets, allowing companies to adapt their strategies to sector-specific and operational conditions. These methods range from linear emission reduction approaches to more complex tools considering carbon intensity per unit of production or sector alignment. Faria and Labutong [
14] describe four such methods, emphasizing the importance of aligning corporate actions with climate science to meet global temperature goals. However, they note that all methods incorporate historical emissions as a basis for future budgets, favoring countries and companies with higher accumulated emissions, creating inequality in the distribution of required reductions. Bjørn et al. [
15] analyzed seven SBT definition methods and found significant variations in emission allocation principles, corporate variables, and global scenarios. The study highlighted frequent imbalances between corporate targets and global emission allowances, influenced by factors like geography, economic sector, and company growth rates, stressing the need for context-specific methods to ensure alignment with global climate goals.
The application of SBT methodologies reflects significant inequalities between wealthy and poorer countries, showing a gap in the global integration of science-based targets. Studies reveal that SBT adoption is still limited in low- and middle-income countries, emission-intensive sectors, and small- and medium-sized enterprises, while large corporations in developed regions, like Europe, dominate the adoption of targets. In 2021, European companies accounted for over half of the approved SBTs, with the majority of the remaining share coming from North American and Asian companies. Meanwhile, Latin America, Africa, and Oceania combined for less than 6% [
11]. This disparity is linked not only to a lack of resources and infrastructure but also to a disconnect between corporate targets and national climate contributions.
While SBTi focuses on emissions reduction, it may not fully address the broader sustainability goals, including social equity and economic stability, which are crucial for the power sector’s sustainable development. Immink et al. [
16] point out that SBTi methodologies fail to adequately consider equity principles and common but differentiated responsibilities, burdening companies in more vulnerable contexts, while others contribute insufficiently to global emission mitigation. This inequitable approach undermines the universality of targets and may perpetuate existing inequalities. It is clear that the Global South, where the adoption of science-based targets is still limited, faces specific challenges such as insufficient infrastructure, lack of access to adequate financing, and weaker regulatory and market pressures for sustainable practices. Additionally, many Latin American companies, particularly small and medium-sized ones, have limited resources to invest in robust emission mitigation strategies or cover the costs associated with certification and target validation. These factors highlight the need for a more detailed regional analysis, identifying key barriers and opportunities for increasing SBT adoption in Latin America.
Despite various criticisms of the SBTi, Maia and Garcia [
17] identified benefits of adopting SBTs by energy sector companies. Companies that adopt targets perform significantly better in terms of emission reductions and transition to renewable energy, although the adoption of SBTi may be more a reflection of geographical and marketing contexts than a direct cause of emission reductions.
Studies such as those by Giesekam et al. [
3] show significant progress in implementing Scope 1 and 2 SBTs, while Scope 3 remains challenging due to lower control over these emissions. The SBTi reported a 25% reduction in Scope 1 and 2 emissions between 2015 and 2019, exceeding the requirements for a 1.5 °C scenario.
The SDA methodology, developed by Krabbe et al. [
10], was created to translate global GHG reduction targets into the corporate level, aligning them with the carbon budgets needed to limit global warming to 2 °C. Based on global mitigation scenarios such as the 2DS from the International Energy Agency (IEA) [
18], the SDA defines carbon intensity pathways specific to each sector, considering activity projections and the initial performance of companies. The method aims to ensure that corporate emissions remain within sectoral limits while promoting the gradual convergence of companies’ carbon intensities to the sectoral average by 2050.
The SDA presents significant innovations by integrating sector-specific characteristics, such as costs and mitigation potentials, and by considering the projected growth of business activities. One of the pillars of the methodology is ensuring that total emissions targets for all companies within a sector do not exceed the sectoral carbon budget. Additionally, the methodology considers the current performance of companies, allowing for a fair and gradual transition toward global climate goals.
The methodological section of the SDA describes how sectoral emissions pathways are translated into company-specific intensity pathways. The process uses physical indicators (such as tons of steel produced) or monetary indicators (such as value added) to relate emissions to activity levels. This approach is particularly effective for sectors with uniform products or activities, as it allows for a more accurate correlation between emissions and business operations [
10].
While the SDA is widely applicable and innovative, it has gaps that limit its effectiveness in certain contexts. For example, the methodology does not differentiate between manageable and non-manageable emissions, which may lead to distortions in regulated or predominantly renewable markets. Additionally, the focus on carbon intensity targets for homogeneous sectors may be inadequate for companies that already operate with renewable sources or those facing temporary high emissions during the expansion of new assets. These challenges highlight the need for methodological adaptations to increase the effectiveness and representativeness of the SDA in specific contexts.