Holding Sustainability Promises in Politics: Trends in Ecosystem and Resource Management in Electoral Party Manifestos

1. Introduction

The Millennium Development Goals (2000-2015) and their evolution into the Sustainable Development Goals (SDGs; 2015-2030) aim to address the world’s most pressing challenges by 2030, covering economic, social, and environmental dimensions. Out of the 17 SDGs, SDG 6 (Clean Water and Sanitation), SDG 12 (Responsible Consumption and Production), SDG 14 (Life Below Water), and SDG 15 (Life on Land) share several commonalities, as they all focus on ensuring environmental sustainability and promoting the responsible use of natural resources [1]. However, we draw particular attention to those directly related to the sustainable management of ecosystems and natural resources: SDG 12 (responsible consumption and production), SDG 14 (life below water), and SDG 15 (life on land) [see 2]. According to Reid, et al. [3], ‘Healthy Ecosystems (Goals 14–15), drawn on by responsible consumption and production (Goal 12), can lead to energy, food and water security as immediate outcomes’. Therefore, we aim to concentrate our specific focus on the SDGs themselves rather than their broader outcomes. This approach prevents our analysis from becoming overly broad and losing focus on sustainable ecosystem and natural resource management, as exemplified by the inclusion of SDG 6.

SDGs 14 - 15 are interconnected and play a crucial role in promoting the biodiversity conservation and the management of natural resources in our planet. Both these SDGs are foundational for a paradigm shift towards novel sustainable development models, such as the bioeconomy, underpinning the blue economy (SDG 14) and fostering a sustainable terrestrial bioeconomy (SDG 15). Additionally, the development of the bioeconomy in general greatly enhances other SDGs such as SDG 12 [4]. Cernev and Fenner [5] advocate that responsible consumption and production (SDG 12) can enhance resource efficiency by minimizing not only waste, through recycling, reusing materials, and promoting more efficient industrial processes, but also by supporting biodiversity (SDGs 14-15) as these are less exploited under this model. Thereby, whether SDG 12 influences or is influenced, it can be associated with the conservation and sustainable use goals of SDGs 14-15. In the end, they are connected through their emphasis on sustainable exploitation and management of natural resources.

However, holistic approaches to environmental sustainability that address both marine and terrestrial ecosystems together with their resources are scarce in the literature, possibly due to sectoral focus or the complexities of interactions and compromise between SDGs targets as they are intend to be complementary and not conflicting. That is why some authors claimed for more integrated approaches [6]. Either way, policy plays a pivotal role in setting a sustainable agenda that favours this holistic approach [7]. Various actors are involved in sustainable policy-making, including individual and collective entities like academia and civil society organizations, as well as key democratic institutions such as national governments [8] and national parliaments [9]. However, ‘this field still lacks studies of political institutions exploring how the 2030 Agenda is brought into national policy-making processes’ [10]. To bridge this gap, electoral manifestos offer valuable insights into the evolving agendas of environmental policies [11].

Our primary contribution aims to analyse political positions regarding the 2030 Agenda, with a particular focus on SDG 12, SDG 14, and SDG 15, the only specific SDGs identified as ‘major challenges’ in Portugal by Lafortune, et al. [12]. Despite being recently classified as ‘major challenges’ (see [12]), Firoiu, et al. [13] revealed that the country has high achievement rates for SDGs 14 and 15, but a low achievement rate for SDG 12. In fact, Portugal faces significant challenges in fully adopting circular economy principles compared to some other European nations, particularly in the private sector [14]. However, to date, and to the best of our knowledge, there are no studies on the evolution of the political agendas in Portugal for the abovementioned SDGs.

In this context, Portugal presents an interesting case within the framework of the UN 2030 Agenda. Portugal does have the largest maritime zone (Exclusive Economic Zone) of the European Union, and 86% of Portuguese forests are privately owned [15], unlike in many other countries where forests are typically state-owned or managed as public lands. Furthermore, Portugal’s political instability with successive general elections (2019, 2022 and 2024), provides now a unique chance to examine diverse electoral manifestos and evolving environmental policies in a short timeframe. Therefore, the aim of this paper is to analyse the manifestos of the Portuguese political parties in the general elections to better understand their environmental policy agenda within the framework of SDG 12, SDG 14, and SDG15. Given its reliability in comparing electoral manifestos [16,17], we conduct a content analysis of manifestos from the Portuguese general elections in 2019, 2022, and 2024. The exploratory nature of this study, vital for advancing science [18], seeks to address specific research questions.

To summarise, we offer insights aimed at refining the environmental political agendas, categorised either by ideology on a spectrum from left to right or by their affiliations within the political groupings of the European Parliament. Subsequently, we reinforce that our contribution seeks to enhance the (weak) theoretical framework connecting political positions to the 2030 Agenda. This broadens knowledge across the left-to-right politic al spectrum and explores how European party affiliations address SDGs, providing valuable insights into pathways for achieving the 2030 Agenda.

2. Theoretical Framework

Portuguese Political Context and Partisanship

Portugal has undergone significant democratic development since the Carnation Revolution on April 25, 1974, which marked the beginning of the country’s transition to democracy and its inclusion in the global “third wave” of democratization [19]. Portugal adopted a semi-presidential system with the 1976 constitution, specifically the ‘president-parliamentary’ type [20], which is characterized by three main branches: Government, Parliament, and the Presidency [21]. Within this system, the Government, accountable to both Parliament and the Presidency, plays a central role in policy formulation, with the Prime Minister being the key figure, along with their cabinet, in initiating policies across various sectors [22,23].

Portugal’s political landscape features a diverse array of parties, yet their clearly defined ideological positions allow for a distinct separation between left and right-wing groups [24]1. On the left-wing, the Socialist Party (SP) stands out as a dominant force [25], alongside the Portuguese Communist Party (PCP), the Left Bloc (LB), and more recently, Livre [26] and the People-Animals-Nature (PAN) party2. On the right-wing, the Social Democratic Party (SDP) and the CDS-People’s Party (PP) have historically played significant roles [30], with the Liberal Initiative (LI) and the radical right party called Chega reaching out the Parliament after the 2019 elections [31]. Since the establishment of Portuguese democracy, all Prime Ministers have come from either the SP or the SDP. The SP, commonly recognized as center-left, emphasizes social welfare, public services, and redistributive policies, while the SDP, identified as center-right, focuses on economic growth, reducing state intervention, and promoting private sector development [32].

The SP has been in power for the last eight years under the leadership of António Costa, who became the fourth President of the European Council. However, the 2024 general election marked a shift, resulting in a right-wing coalition between the SDP and the PP. This trend was reinforced in the anticipated general elections of 18 May 2025, which also saw a significant rise in support for the far-right party Chega. As in 2024, Luís Montenegro won the election and was once again appointed to form a minority government. In addition, Portugal has a President supported by both SDP and PP, and the Parliament’s composition illustrated in Figure 1 (from left to right-wing spectrum). Portuguese parties retain their affiliations with European parliamentary groups as shown in Figure 1. PCP and LB are aligned with The Left group in the European Parliament (The Left), while Livre and PAN are associated with the Group of the Greens/European Free Alliance (Greens/EFA). SP relates to the Group of the Progressive Alliance of Socialists and Democrats in the European (S&D), and SDP and PP are part of the Group of the European People’s Party (EPP). JPP and LI are affiliated with Renew Europe Group (Renew), and Chega is associated with Patriots for Europe (PfE), a splinter group from the former Identity and Democracy.

Electoral Manifestos

Government Public policies and initiatives are outlined in the government programme, which is largely shaped by the electoral manifesto of the winning party or coalition [33,34]. As a key guide for a campaign and an essential tool in political science [35], an electoral manifesto can be seen as a promissory agenda of the winning party or coalition, designed to adapt to shifts in public concerns and to address unexpected events and new challenges as they arise [36]. Beyond external pressures, minority governments are generally more open to negotiating with other parties on additional policies for implementation [37]. As shown by Krauss and Thürk [38], minority governments that lack formal support agreements with non-cabinet parties face a significantly higher risk of early termination.

While opposition manifestos are important in any government setup, their role becomes particularly significant in a minority government as it can influence policy outcomes and the legislative process through negotiation, public advocacy, and strategic positioning [39]. In Portuguese general elections, Borghetto and Belchior [11] show ‘that electoral agendas drive policymaking’, while Belchior [40] argues that ‘political parties tend to deliver on their campaign promises’. In this scenario, the compatibility of party goals and the specific conditions of partisan bargaining influence the government’s negotiating power, as well as the incentives for non-cabinet parties to either cooperate or obstruct the process are crucial [41].

Electoral manifestos, whether from opposition or ruling parties, are central to shaping policymaking across multiple domains [42,43]. This has been evident in studies examining the relationship between political commitment and environmental sustainability [44,45,46], as well as in the context of some specific SDGs: SDG 5 [47], SDG 7 [48], SDG 13 [49,50]. Considering this and recognizing that sustainable development has become an increasingly prominent topic [51], we aim to determine whether the manifestos indicate or not a positive evolution, leading us to the following research question: [RQ1] What is the evolution of SDG12, SDG14, and SDG15 as reflected in electoral manifestos? Moreover, [RQ2] Do electoral manifestos maintain a balance between SDG 12, SDG 14, and SDG 15?

On the one hand, SDGs 14 and 15 are crucial for biodiversity conservation and are interconnected through their emphasis on sustainable natural resources management [52]. These goals are foundational for promoting sustainable development models like the bioeconomy, with SDG 14 supporting the blue economy and SDG 15 fostering a sustainable green bioeconomy. The growth of the bioeconomy also enhances other SDGs, particularly SDG 12 [4]. According to Cernev and Fenner [5], responsible consumption and production (SDG 12) can boost resource efficiency by minimizing waste through recycling, reusing materials, and improving industrial processes, which in turn supports the conservation efforts of SDGs 14 and 15. Therefore, SDG 12 is both influenced by and contributes to the goals of SDGs 14 and 15, highlighting their interconnectedness in promoting the sustainable use of natural resources.

On the other hand, some authors contend that there is no correlation between SDG 14 and SDG 15 [53], or that only one target of SDG 14 (target 14.5) shows a positive correlation with SDG 15 [54]. Fonseca, Domingues and Dima [53] also suggest that SDG 12 is negatively correlated with SDG 14 or not correlated with SDG 15. Additionally, Pradhan, et al. [55] argue that both SDG 12 and SDG 15 function as trade-offs, where progress in both SDG 12 negatively impacts the progress of other SDGs or vice-versa.

The ongoing debate among academics regarding the synergies and trade-offs between SDGs raises the following research question: [RQ3] Is there any correlation between SDG 12, SDG 14, and SDG 15 as reflected in electoral manifestos?

Despite the importance of electoral manifestos as drivers of policy, the SDGs in general can be taken up as an element of tension in the political arena, with various stakeholders - such as activists, civic movements, industry groups, and environmental organizations - playing key roles in influencing sustainable policies [see 56–58].

Partisanship and SDGs

‘Ideological orientation is one of the most important factors in explaining political attitudes, perceptions and behaviour’ [59]. In fact, parties ideologies can have a role in the way and extension of SDGs are achieved [60,61], while political partisanship significantly influences sustainable and environmental attitudes [62].

Some authors pointed out that left-wing parties tend to be more committed to Sustainable Development Goals (SDGs) compared to their right-wing counterparts [44,63]. This trend can be attributed to the left-wing’s general association with positive attitudes toward equality, redistribution, government intervention, social justice [64], and progress in gender equality [65]. Furthermore, individuals with a left-wing political orientation have been associated with more favourable attitudes toward environmental sustainability [66,67]. At the local level, cities with left-wing leadership and a higher number of green party representatives on the city council are more likely to apply for the European Green Capital Award [68].

While right-wing parties may prioritize different aspects compared to left-wing parties, their policies and characteristics can still play a significant role in advancing certain SDGs. For example, in the environmental domain, individuals with right-wing orientations often express significant concern about the increasing amount of waste and its treatment processes [69]. Additionally, right-wing parties often promote the adoption of new technologies in various countries [70] and facilitate green innovation, as evidenced by a study covering OECD nations [71]. Right-wing parties, recognized for advocating private sector involvement and market dynamics, can support public-private partnerships and foster an enterprise ecosystem that enhances sustainable development, with implications in the management of water, energy and food [see 72].

Despite these findings, some authors observed no differences between the political spectrum (left-right) in the implementation of SDG policies at the local level in Spain and Italy [73]. Other authors have argued that both political wings adjust their sustainability positions depending on whether they are in government or in opposition [74]. Hence, the question remains: [RQ4] Do left-wing and right-wing electoral manifestos differ in their coverage of SDG 12, SDG 14, and SDG 15?

Different sustainability agendas exist across EU political groups. The approach to sustainability varies significantly depending on the ideological orientation of each political group [75]. General areas and topics to explore for relevant research on the differences in sustainability agendas across EU political groups include examining their strategic guidelines. As sustainable and environmental issues gain popularity [51], some authors have identified a relationship between populism and sustainable development in various countries [76]. In this context, although there is a well-documented ideological connection between the far right and the natural environment [77], environmental and sustainability issues have increasingly shifted to being inclusive themes championed by the left-wing [78]. Consistent with the positions of some conservative parties [79,80], there is substantial evidence that far-right parties and their supporters often deny, or are skeptical of, the existence of anthropogenic climate change [81,82,83]. However, in recent years, far-right parties in Europe have started to engage with sustainability issues defending eco-nationalism, eco-fascism, or far-right ecologism [84,85]. Despite this shift, they remain significant obstacles to the EU’s sustainable development agenda [86]. Whether driven by opportunism or by party ideology (which may be more or less aligned with sustainability themes), the question remains: [RQ5] Do electoral manifestos differ based on the European party affiliation concerning SDG12, SDG14, and SDG15?

3. Materials and Methods

3.1. Sample and Research Design

This study examines a sample of 24 electoral manifestos from the 2019, 2022, and 2024 Portuguese general elections using content analysis, a method still frequently employed to compare electoral manifestos across various domains [16,17,87]. With nearly 4,000 pages in total, each manifesto averages 164 pages. It should be noted that only parties represented in the last Portuguese Assembly and parties having their own manifesto were analysed3.

Rather than conducting an inductive content analysis, a deductive approach is more suitable to test or validate existing theories, knowledge or pre-established frameworks [88]. As the UN SDGs are based on existing knowledge and established framework [89], the option falls on a deductive approach. This approach offers a clear structure and focus through predefined categories, promoting consistency in coding and interpretation by using established frameworks [90].

Given our focus on quantitative data analysis and research question answering, we employed a summative and latent content analysis strategy [91], diverging from the thematic analysis approach advocated by Nowell, et al. [92]. Figure 2 provides a visual representation of our deductive methodological framework, outlining the steps of summative and latent content analysis; in other words, a partial Latent Projective Content Analysis.

3.2. Coding Scheme

In accordance with the methodology outlined by Villiger, et al. [94], the coding scheme was subjected to a pre-test using a sample of Portuguese electoral manifestos from four randomly chosen parties spanning three years. To guarantee the reliability and comprehensiveness of the analysis, peer review of the raw data was conducted in line with the suggestions of McDonald, et al. [95] and Neuendorf [96]. The coding scheme to the content based on the keywords in the fields ‘UoA Text-Mining Results (global publications)’ AND ‘UN SDG Targets and Indicators’ provided by Wang, et al. [97] was applied for SDG 12, 14, and 15 – see Appendix A (Table A1, Table A2 and Table A3). In accordance with the guidelines of Erlingsson and Brysiewicz [98], a uniform coding scheme of up to short keywords per SDG was applied to each electoral manifesto to ensure consistency throughout the study.

3.3. Data Analysis and Procedures

In comparing SDGs aggregated by political spectrum, the results were weighted according to the number of political parties at both the national level (left or right-wing) and the European level (political groups in the European Parliament). To answer our research questions, we performed comparisons using parametric mean tests, Pearson correlations, and one-way analysis of variance (ANOVA). Consistent with Krippendorff [99] application of basic statistical methods in content analysis, these procedures facilitate the systematic analysis of data, enabling the identification of patterns, trends, and differences within the content of electoral manifestos. The majority of the data was analysed using MAXQDA version 24, with additional support from SPSS version 29, R software, version 4.2.1, and WordArt.com for specific tasks.

4. Results

4.1. Aggregate Results

Regarding descriptives and univariate normality assessment, Table 1 shows the statistics by each SDG in analysis according to the 24 electoral manifestos.

Frequency of coding has significantly more weight for SDG 15 compared to the other remaining SDGs, and more data dispersion across electoral manifestos (SD = 38.19). In summary, concerning the reference values established by George and Mallery [100], where |Sk| > 2 indicates marked asymmetry and |Ku| values > 2 indicate marked kurtosis, none of the variables significantly deviated from univariate normal distribution assumptions. To validate these assumptions, we conducted several normality tests for the SDGs, assuming normal distribution of the data. Table A4 suggests that data follow a univariate normal distribution, enabling the use of further parametric procedures.

The data presented in Table A5 provides additional context for the Figure 3, which illustrates that the quantity of SDG-related codes in electoral manifestos has remained relatively constant across the three election cycles examined. From a statistical standpoint, this is confirmed by a one-way ANOVA, which shows no statistically significant differences in all analysed SDGs across the electoral years: (F(2,21) = 0.123, p = .885 [SDG 12]; F(2,21) = 0.110, p = .897 [SDG 14]; F(2,21) = .134, p = .876 [SDG 15]) - see Table A6.

Overall, Figure 3 illustrates a significant disparity, with SDG 15 having around 400 related codes, whereas the remaining SDGs have between 100-200 related codes, approximately. This highlights the substantial emphasis placed on SDG 15 in electoral manifestos.

In addition to the observed stagnation of SDGs in electoral manifestos over time, Pearson correlation can be used to understand the linkages between SDG topics covered by each electoral manifesto during the same period. Figure 4 shows a positive and statistically significant correlation between the analysed SDGs in electoral manifestos. According to the correlation strength classifications proposed by Schober, et al. [101], the analysis reveals positive strong associations (correlation coefficients between 0.70 and 0.89) linking SDG 12 with SDG 14, as well as SDG 12 with SDG 15. Additionally, a positive and moderate relationship (correlation coefficients between 0.40 and 0.69) is observed between SDG 14 and SDG 15. In summary, SDG12, SDG14, and SDG15 are moderate-strongly correlated based on the number of SDG-related codes found in electoral manifestos.

Figure 5 presents the top 5 most frequent SDG-related codes, representing 47.3% of all codes identified in SDG 12, 41.7% of all codes identified in SDG 14, and 49.7% of all codes identified in SDG 15. For SDG 12, Figure 5 highlights two codes associated with circular processes, two with efficiency, and one general code (Environmental Policy). For SDG 14, Figure 5 presents the top four items related to Integrated Marine Science and Management, with the fifth item focusing on the cultivation of marine life for economic purposes (Aquaculture). For SDG 15, Figure 5 indicates that all five items pertain to conservation efforts.

4.2. Micro and Grouped Results

A more detailed analysis of the overall findings can be achieved by examining the electoral manifestos from three distinct perspectives: (i) individual political parties, (ii) position on the political spectrum (ranging from left-wing to right-wing), (iii) and Portuguese political parties’ European affiliation. This approach allows for a more nuanced understanding of how different political entities and ideologies address the SDGs.

4.2.1. Individual Political Parties

Figure 6 illustrates the fluctuation in the frequency of SDG-related codes (as a percentage of the total for each SDG) found in electoral manifestos throughout the analysed election cycles. An examination of the electoral manifestos reveals significant variations in both initial levels (baselines) and rates of change (slopes) across different parties. These disparities make it challenging to identify consistent trends or draw parallels between certain parties, which in turn increases the needed effort to establish clear patterns or group parties based on similarities in their SDG coverage. Despite the observed volatility in the data, several noteworthy patterns emerge from the analysis of electoral manifestos across the three election periods:

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Livre is the only party showing consistent growth in all SDG-related code frequency across all elections;

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Chega exhibited minimal or no SDG-related codes in 2019 and 2022 but showed an increase for SDG 15 and expressive increases for SDGs 12 and 14 in 2024, albeit still at relatively low frequencies;

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PAN, despite high SDG-related code frequencies (particularly for SDGs 12 and 15) in 2024, recorded fewer codes across all SDGs compared to 2019;

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SP showed a decrease in SDG-related codes from 2019 to 2024 across all SDGs, with a significant downward trend over the three election periods. However, it led in SDG 14 code frequency in 2024;

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SDP demonstrated the most stable frequency of codes across all SDGs, closely aligning with the average number of frequency codes;

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LB exhibited a concave trend, peaking in code frequency for all SDGs in 2022. A decreasing pattern was noted for SDG 12 in 2024, while SDGs 14 and 15 remained stable when comparing 2019 to 2024;

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LI is characterized by relatively high frequency coding in SDG 12, contrasting with low frequencies in SDGs 14 and 15, rather than showing a clear trend;

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PCP displayed a convex trend, with lower frequency codes across all SDGs in 2022, but recovered to or exceeded 2019 levels in 2024 (particularly for SDG 14).

4.2.2. Position on the Political Spectrum

Beyond temporal trends, the mean frequency of SDG-related codes in electoral manifestos across the three election cycles provides a foundation for deeper analysis along political spectrum lines and European party affiliations. Figure 7 shows how each party’s manifesto compares to the average code frequency for each SDG over the three election periods, highlighting those above and below the mean. Notably, across all SDGs under examination, left-wing party manifestos consistently occupy the top three positions in terms of code frequency.

Analytically, a parametric approach was deemed appropriate for the analysis, given that the data met the necessary univariate normality assumptions. Consequently, we employed an independent samples t-Test to investigate potential disparities between left-wing and right-wing electoral manifestos across the three election cycles. In addition, Levene’s test confirmed homogeneity of variance between the two political wings for all SDGs in analysis (t = .31, p = .58 [SDG 12]; t = .12, p = .73 [SDG 14]; t = 3.67, p = .069 [SDG 15]).

Table 2 reveals statistically significant differences between the two political wings for all SDGs in analysis. Hence, for SDG 12, SDG 14 and SDG 15, we can conclude that the electoral manifestos of left-wing parties have a statistically significantly higher number of code frequency (30.53 codes ± 2.98 [SDG 12] 20.13 codes ± 2.93 [SDG 14]; 64.80 codes ± 9.89 [SDG 15]) compared to those of right-wing parties (26.33 codes ± 6.59 [SDG 12] 8.78 codes ± 2.86 [SDG 14]; 25.78 codes ± 6.55 [SDG 15]); t(22) = 2.220, p = .0185 [SDG12], t(22) = 2.580, p = .0085 [SDG 14] and t(22) = 2.751, p = .0049 [SDG 15]. In other words, the data provides compelling statistical evidence that left-wing electoral manifestos consistently include a higher frequency of codes related to SDG 12, SDG 14 and SDG 15.

The evidence of higher code frequency in left-wing manifestos compared to right-wing ones is more prominent in SDGs 14 and 15 than in SDG 12, although statistical differences were observed across all SDGs between the political spectrums. These facts can be better visualised in Figure 8.

A qualitative approach provides a solid foundation for a more detailed content analysis. This allows us to examine the specific topics emphasized by each political spectrum across all SDGs in analysis. The raw data supporting this analysis can be found in Table A7, Table A8 and Table A9, and is visually represented in Figure 9, Figure 10 and Figure 11.

Considering Table A7 and Figure 9 for SDG 12, there is evidence that left-wing manifestos place greater emphasis on key environmental themes such as the Circular Economy, Efficient Use of Natural Resources, and Environmental Policy compared to their right-wing counterparts. In contrast, right-wing parties show a relatively higher focus on specific topics like Waste Management, Hazardous Waste Management, and Wastewater Treatment. Both political spectrums share a common interest in key areas like Building Energy Efficiency, Renewable Energy, and Waste Recycling, reflecting a mutual concern for sustainability, though the depth and focus of their approaches differ. In total, left-wing electoral manifestos address 60% of the keywords proposed by Wang, Kang and Mu [97], whereas right-wing electoral manifestos cover 46% of those keywords.

According to Table A8 and Figure 10 for SDG 14, both left-wing and right-wing electoral manifestos in Portugal emphasize Marine Ecosystems, Sustainable Fisheries, and Marine Technology, indicating shared concern for ocean health and sustainable use of marine resources. However, left-wing manifestos generally show higher frequencies across most keywords, suggesting more comprehensive coverage of SDG 14 issues. Left-wing electoral manifestos cover 56% of the keywords proposed by Wang, Kang and Mu [97], while right-wing electoral manifestos address 34% of these keywords. Notable differences include left-wing manifestos’ greater focus on Marine Pollution, Marine Protected areas, and Marine Resource Management, while right-wing manifestos give relatively more attention to Integrated Coastal Zone Management and Marine Spatial Planning. Interestingly, Destructive Fishing and Overfishing are exclusively mentioned in left-wing manifestos, potentially indicating differing priorities in fisheries management approaches.

Based on Table A9 and Figure 11 for SDG 15, the analysis shows that both left-wing and right-wing Portuguese electoral manifestos prioritize the keywords Biodivers*, Forest*, and Protected Area. However, while right-wing manifestos rank desertification and drought among their top five concerns, left-wing manifestos place poaching and native species in this top rank, reflecting a stronger emphasis on conservation. Left-wing electoral manifestos prioritize the protection of biodiversity through a strong focus on Threatened and Endangered Species, Habitat Fragmentation, the Endangered Species Act, and combating Invasive Species, highlighting their commitment to conservation over the more resource-focused approach of right-wing parties. In fact, right-wing parties adopt a more utilitarian perspective, concentrating on Land Management and Terrestrial Water Storage. Overall, left-wing manifestos address 55% of the keywords identified by Wang, Kang and Mu [97], while right-wing manifestos cover 30%, highlighting a contrast between conservation-focused approaches and resource management strategies.

4.2.3. Portuguese Political Parties’ European Affiliation

Looking at the number of codes in party manifestos, there were statistically significant differences between parties’ European affiliation for all SDGs as determined by one-way ANOVA: (F(5,18) = 7.30, p = .0007 [SDG 12]; F(5,18) = 2.53, p = .0666 [SDG 14]; F(5,18) = 9.50, p = .0001 [SDG 15]). Table 3 presents the results of a one-way ANOVA, indicating significant differences in the approaches to SDGs among party manifestos based on their European affiliations. In summary, party manifestos show significant differences in their approach to SDGs based on European affiliation for the three election periods (2019/2022/2024).

The statistically observed volatile patterns across the three election periods are graphically depicted in Figure 12. It indicates that in 2024, the volatility for all SDGs across electoral manifestos is less pronounced compared to previous year