Blue Horizons for Resilient Islands: Legal–Technological Synergies Advancing SDG 7 and 13 Through the UNCLOS–Paris Agreement Integration in SIDS’ Energy Transitions

Abstract

Small island developing states (SIDS) face a dual constraint of “environmental vulnerability and energy dependence” in the context of climate change. How to achieve just energy transitions has become a core proposition for SIDS to address. This paper focuses on how SIDS can advance Sustainable Development Goal (SDG) 7 (affordable and clean energy) and Sustainable Development Goal 13 (climate action) through UNCLOS–Paris Agreement integration in energy transitions. Grounded in the theoretical framework of the Multidimensional Vulnerability Index (MVI), this research aims to construct a comprehensive analytical system that systematically examines the energy transition challenges facing SIDS and provide multi-level energy transition solutions spanning from international to domestic contexts for climate-vulnerable SIDS. The research findings reveal that SIDS face a structural predicament of “high vulnerability–low resilience” and the triple challenge of “energy–climate–development”. International climate finance is severely mismatched with the degree of vulnerability in SIDS; the United Nations Convention on the Law of the Sea (UNCLOS) and the Paris Agreement lack institutional synergy and fail to adequately support marine renewable energy development in SIDS. In response to these challenges, this study proposes multi-level solutions to promote the synergistic achievement of SDG 7 and SDG 13: at the international level, improve climate finance rules, innovate financing mechanisms, strengthen technological cooperation, and integrate relevant international legal framework; at the domestic level, optimize the layout of marine renewable energy development, construct sustainable investment ecosystems, and strengthen environmental scientific research and local data governance.

1. Introduction

Since the Industrial Revolution, fossil fuels have been deeply embedded in human energy consumption systems, and the resulting massive greenhouse gas emissions have become the primary driver of global climate change. The consequences of climate change are becoming increasingly apparent: the accelerated melting of polar ice, the continued rise in global sea levels, the intensification of ocean acidification, the increase in the frequency of catastrophic storms, and the sharp decline in biodiversity. The Intergovernmental Panel on Climate Change (IPCC) report clearly pointed out that about 3.3 billion to 3.6 billion people (nearly half of the world’s population) live in areas that are highly vulnerable to climate change [1]. Once global warming exceeds the critical point of 1.5 °C, it will cause irreversible destructive impacts on specific regions and ecosystems.

However, the international community’s actions in climate governance are still lagging behind. The game between different types of countries and interest groups in the international community has made the negotiation process of key issues, such as energy transformation, emission reduction commitments, climate finance, and technical assistance, full of hardships. The global climate governance mechanism is weak. On January 27, 2025, the United States once again announced its withdrawal from the Paris Agreement, further exacerbating the uncertainty of global climate governance and making global climate action face more severe challenges [2].

Although the impact of climate change is global and systemic, the different stages of development of various countries, the hidden transfer of climate costs, and the lack of substantial climate aid have led to an extremely uneven distribution of climate damage in different countries and regions [3,4]. SIDS, which have made the “least contribution” to climate change and have the weakest response capabilities, often bear the most serious adverse effects of climate change. The total carbon emissions of these island countries account for less than 1% of the world’s total, but against the backdrop of an average annual rise of 3.7 mm in global sea levels, they are facing severe challenges at the survival level, such as shrinking or even disappearing land areas and damaged marine rights and interests [5,6]. The dual constraint of geographical vulnerability and fossil energy dependence is pushing SIDS toward a “climate poverty trap”, creating increasingly significant risks for achieving SDG 7 and SDG 13.

As illustrated in Figure 1, a co-occurrence analysis of the literature retrieved from the Web of Science database using the keywords “sustainable development” and “SIDS” reveals that existing research on sustainable development in small island developing states exhibits distinctly compartmentalized and fragmented characteristics. For instance, Dornan focuses primarily on techno-economic challenges of electricity access [7], while Wolf et al. concentrate on the climate impacts of tourism [8]. Concurrently, the analysis visually demonstrates that energy transition has emerged as an increasingly prominent focus within SIDS sustainable development research, reflecting a consolidated academic consensus on its urgency.

Regarding the technical feasibility of energy transition, although techno-economic assessments by Nordman et al. on Cape Verde and Rogers et al. on Barbados demonstrate that SIDS possess the technical potential for renewable energy transition, such studies often overemphasize economic and technical dimensions while lacking in-depth institutional design analysis [10,11].

In the field of climate vulnerability and adaptation research, existing studies have thoroughly analyzed the multidimensional risk challenges facing SIDS, such as sea-level rise threats revealed by Vousdoukas et al. and adaptation requirements under 1.5 °C warming scenarios analyzed by Mycoo [12,13]. However, these studies primarily focus on passive adaptation measures, remaining at the problem-diagnosis level. More critically, existing research lacks analytical frameworks that systematically integrate SDG 7 and SDG 13, failing to adequately explore the dual value of marine renewable energy in simultaneously advancing energy security and climate resilience.

Concerning SIDS governance and policy coordination research, Scobie’s analysis of policy coherence in the Caribbean region and Robinson’s study on adaptation mainstreaming reveal institutional fragmentation issues within existing governance architectures [14,15]. However, these studies are primarily limited to domestic policy levels, lacking in-depth exploration of how international legal frameworks can provide systematic support for SIDS’ energy transition through institutional integration.

In international cooperation and financing mechanism research, Thompson emphasizes the importance of science diplomacy, while Horan proposes a partnership framework based on SDG interconnectedness [16,17]. Nevertheless, related research primarily remains at the stakeholder identification level, lacking comprehensive examination of the legal institutional integration mechanisms that underpin these partnerships, particularly in the critical area of energy transition.

Consequently, while existing research has achieved significant progress in individual dimensions such as technical feasibility, climate vulnerability, and governance mechanisms, it lacks systematic cross-disciplinary integration perspectives and targeted specific analysis of the connections between SDG 7 and SDG 13.

The complexity of SIDS’ energy transition issues determines that this is neither merely a technical problem nor solely a climate governance issue, but rather a comprehensive challenge requiring coordinated solutions across legal, technical, economic, and environmental dimensions. Therefore, this paper transcends traditional international law sectoral barriers and moves beyond vulnerability descriptions, aiming to provide a comprehensive analytical framework centered on the institutional integration of the UNCLOS and the Paris Agreement. It systematically examines the energy transition challenges faced by climate-vulnerable SIDS, evaluates the strengths and deficiencies of existing international legal frameworks in supporting SIDS’ energy transition, and accordingly proposes targeted recommendations for constructing an integrated governance system from international legal frameworks to domestic institutional arrangements, helping SIDS build resilient transition pathways and promote collaborative achievement of SDG 7 and SDG 13.

The structure of this paper is as follows: Following the introduction, the Section 2 elaborates on the research methodology, including comprehensive research methods, data collection approaches, legal analytical frameworks, and research limitations. The Section 3 systematically presents research findings through in-depth analysis across four dimensions: environmental vulnerability of SIDS, current energy development status, resilience financing conditions, and the status of relevant international legal frameworks. The Section 4 advances a critical discussion, analyzing core issues and causes—including environmental challenges, energy transition dilemmas, financing difficulties, and insufficient international institutional supply—that SIDS face. The Section 5 proposes targeted recommendations, constructing multidimensional solutions from both international and domestic levels. Finally, the Section 6 summarizes the entire paper, emphasizing that climate change, energy transition, and international legal frameworks constitute an inseparable triangular relationship, providing systematic theoretical guidance and practical pathways for SIDS to collaboratively achieve SDG 7 and SDG 13.

SIDS’ energy transitions are not merely simple “de-fossil fuelization” processes, but systematic transformations requiring consideration of multiple objectives including energy security, economic development, environmental protection, and social justice. Against the backdrop of severe challenges facing global climate governance, providing effective support for SIDS as the most vulnerable group of countries is not only an ethical requirement for achieving climate justice but also a key indicator for testing the effectiveness of the global climate governance system. This study aims to provide useful references for SIDS’ energy transitions and sustainable development while making positive contributions to improving global climate governance.

2. Materials and Methods

2.1. Research Approach

This study employs a comprehensive research methodology combining normative analysis, case studies, and interdisciplinary research. Through normative analysis, the study evaluates promotional and constraining factors of existing international legal frameworks on SIDS’ energy transitions. Through case analysis, it examines practical experiences and lessons from typical SIDS energy transition practices. Through interdisciplinary research methods, it integrates legal rules with scientific knowledge to assess the effectiveness of current legal norms in ensuring environmental benefits during SIDS’ energy transition processes.

2.2. Data Collection Methods

This paper utilizes data related to SIDS’ climate change, climate governance, and energy transitions from reports by international organizations including the World Bank (WB), International Renewable Energy Agency (IRENA), United Nations Environment Programme (UNEP), World Meteorological Organization (WMO), and Organisation for Economic Co-operation and Development (OECD). These reports provide detailed analyses of climate change impacts on society, economy, and ecology, as well as information on the role and shortcomings of international cooperation. By extracting, integrating, and analyzing this effective information and data, the study directly observes universal challenges faced by SIDS in energy transitions, helping to map SIDS’ pathways for synergistic achievement of SDG 7 and SDG 13.

Additionally, considering four elements—geographical diversity, developmental stage differences, legal practice innovation, and data availability—this paper selects representative countries of SIDS for specific analysis and examples. Specifically, first, the research ensures coverage of representative countries across three major regions. For example, Pacific Island nations such as Fiji and Tuvalu, Caribbean countries including Barbados and Dominica, and AIMS region states such as Cape Verde and Seychelles. Second, by comparing advanced transformation leaders (exemplified by Tuvalu and Fiji), steady progression achievers (represented by Mauritius and Cape Verde), transformation laggards (including Trinidad and Tobago and Bahrain), and volatile transformation cases (such as Belize), the study demonstrates the varied developmental stages among different SIDS. Finally, the research emphasizes breakthrough cases in policy instruments, such as Seychelles’ blue bond financing model, Mauritius’ comprehensive incentive policy framework, and Cape Verde’s integrated wind and ocean energy development, providing replicable experience templates for other SIDS.

2.3. Legal Analysis Framework

The international legal framework supporting SIDS’ energy transition exhibits multi-tiered characteristics, encompassing global treaties, regional initiatives, and soft law instruments. Among these, the UNCLOS and the Paris Agreement serve as foundational global treaties providing essential legal underpinnings. Regional instruments such as the Framework for Energy Security and Resilience in the Pacific (FESRIP 2021–2030) offer more targeted institutional arrangements tailored to specific geographic contexts. While the Barbados Programme of Action [18], the SAMOA Pathway [19], and the 2030 Agenda for Sustainable Development [20] constitute international soft law without binding legal force, they function as significant international political commitments. These instruments reflect the international community’s deepening recognition of SIDS’ unique vulnerabilities and requirements, thereby establishing a coherent international policy environment that facilitates energy transition initiatives across small island developing states.

This multi-layered legal architecture creates complementary pathways for SIDS to pursue sustainable energy transformation while addressing their distinctive developmental challenges and climate vulnerabilities within established international frameworks.

2.4. Research Limitations

2.4.1. Data Availability and Representativeness Limitations

This study uses 38 SIDS in UN member states as the basic research object [21]. However, the research process faces significant challenges in data availability. First, due to unsystematic statistical collection in some SIDS, obtaining complete datasets presents substantial difficulties. This data incompleteness may impact micro-analysis of specific issues. However, by comparing multi-source data through triangulation and using sampling representativeness verification, the data obtained are statistically representative of the overall characteristics of the SIDS population [22]. Data bias is mainly manifested in uneven coverage rather than systematic errors, therefore insufficient to fundamentally affect identification and analysis of universal problems faced by SIDS. Based on reliability testing, research conclusions remain within scientifically reasonable confidence intervals, maintaining robustness of research findings.

2.4.2. Epistemological Limitations of Interdisciplinary Research

As an interdisciplinary study between international law and environmental science, this research faces inherent challenges in disciplinary integration. While this study strives to combine environmental science evidence with legal analytical frameworks, limitations exist in detailed interpretation of environmental science data, comprehensive understanding of ecosystem dynamics complexity, and precise correspondence between environmental indicators and legal concepts. This reflects inherent tensions between the descriptive nature of environmental science and the normative logic of law.

3. Results

3.1. Environmental Vulnerability of SIDS

The MVI is a new quantitative benchmark for assessing multiple dimensions of vulnerability and resilience in national sustainable development. The construction of this comprehensive indicator stems from profound reflection by the international community on existing single-indicator assessment systems, recognizing that traditional measurement methods based solely on national income cannot adequately capture multi-dimensional characteristics of national development and systemic challenges they face [23]. In 2024, the UN General Assembly’s resolution on the “Multidimensional Vulnerability Index” clearly established MVI’s strategic position as a key tool for assessing the special circumstances of SIDS, forming a complementary rather than substitute relationship with Gross National Income per capita (GNI PC) [24].

The theoretical framework of MVI consists of two core pillars: structural vulnerability and resilience (Figure 2). Structural vulnerability assesses a country’s sensitivity to external shocks, while resilience measures a country’s inherent capacity to respond, adapt, and recover from these shocks. This paper employs this multi-dimensional assessment framework to better understand SIDS’ high structural vulnerability and low resilience under climate change contexts.

The MVI employs a 0–100 scale and represents a standardized fragility index, where higher scores indicate greater national fragility. Through systematic analysis of MVI data, small island developing states demonstrate significant and universal environmental vulnerability characteristics. As shown in

Table 1. Summary statistics by groups.

Groups	All Developing Countries	SIDS
MVI Average by group	52.9	56.63
MVI median by group	52.8	57.04
MVI SD by group	8.4	6.91

Notes: This table counts 37 SIDS. The design objective of the MVI is to measure the structural vulnerability of developing countries for the purpose of guiding the allocation of development assistance and concessional financing. As a high-income, developed nation, Singapore does not align with the target beneficiary profile of this index, and therefore was appropriately excluded from the research framework. Source: [25].

, SIDS’ average MVI value reaches 56.63, not only higher than the average level of all developing countries (52.9), but with a relatively small standard deviation (6.91). Of all SIDS, 70% have scores in the top 50% of the distribution (above the median). This statistical characteristic reveals common and universal vulnerability challenges faced by the SIDS group, reflecting collective characteristics of their structural environmental sensitivity.

Sachs and other scholars, as an important academic response to UN General Assembly Resolution 75/215, conducted a detailed regional differentiation analysis of SIDS’ environmental vulnerability. The environmental vulnerability dimension primarily measure the frequency, intensity, and impact of natural disasters. While these events have significant effects on Small Island Developing States, they exhibit relatively sparse distribution patterns in statistical data. For example, indicators such as the proportion of economic losses from natural disasters relative to GDP and the ratio of deaths from meteorological disasters to total population typically show relatively small absolute values, even in the most vulnerable countries. The study revealed a clear regional gradient: SIDS in the Pacific region showed the most prominent environmental vulnerability index (about 10.5), followed by the Caribbean region (about 8.8), and the AIMS region (Africa, Indian Ocean, Mediterranean, and South China Sea) was relatively low but still maintained at a high level (about 5.7) [26]. It is worth noting that the environmental vulnerability of all SIDS regions is significantly higher than the global average (about 2.8), highlighting the common but varying degrees of environmental challenges faced by these island countries.

3.2. SIDS Energy Development Status

A notable fact is that SIDS, as a special category of developing countries, generally possess vast exclusive economic zones and abundant marine renewable energy resources, yet most of these resources remain underutilized. Located primarily in tropical or subtropical regions where the sea area typically exceeds land area by hundreds of times, these countries have enormous potential for developing offshore wind, wave, tidal, and ocean thermal energy.

Table 2. Overview of average energy sector indicators for SIDS.

Indicator	Value	Notes
Average share of fossil fuels in power mix	84%
Percentage of SIDS subsidizing fossil fuels	60%	Averaging 0.6 percent of GDP
Transmission and distribution (T&D) losses	18%	the global average: 8%
Average grid capacity	236 MW	45 percent of the SIDS possess power systems with capacities below 60 MW
Average variable renewable energy (VRE) share in electricity generation	3%	Over 50% of SIDS have no utility-scale VRE generation; Barbados leads at 16%
Average renewable energy penetration	20%	Including hydropower and geothermal power projects

Note: Due to data constraints, the analysis in this report centers on 20 out of the 38 SIDS spanning. The Caribbean (Antigua and Barbuda, Barbados, Belize, Dominica, Grenada, Jamaica, St Lucia, St Vincent and the Grenadines), the Pacific (Papua New Guinea, Timor-Leste, Tonga, Tuvalu, Vanuatu), Africa (Cape Verde, Comoros, Guinea-Bissau, Sao Tome and Principe), and the Indian Ocean (Maldives, Mauritius, Seychelles). Source: [27].

data shows that SIDS’ energy systems face multiple challenges.

First, high fossil fuel dependence: an average of 84% of electricity comes from fossil fuels, leading to energy security concerns and high carbon emissions. Second, widespread existence of fossil fuel subsidies: 60% of SIDS provide fossil fuel subsidies, averaging 0.6% of Gross Domestic Product (GDP), which not only burdens fiscal finances but also hinders clean energy investment. Third, low grid efficiency: 18% transmission and distribution loss rates significantly exceed the 8% global average, reflecting infrastructure aging and technical limitations. Fourth, limited grid scale: the average grid capacity is only 236 MW, with 45% of SIDS’ power system capacities below 60 MW, limiting economies of scale effects. Fifth, low renewable energy penetration rates: SIDS countries’ average renewable energy penetration is only around 20%. These factors collectively constitute an energy poverty trap: high oil prices lead to high electricity prices, while inefficient infrastructure further exacerbates economic burdens of energy access.

Figure 3, Figure 4 and Figure 5 reveal obvious regional differences and temporal evolution in SIDS’ renewable energy development.

Pacific region: Fiji and Tuvalu perform prominently, with renewable energy proportions reaching 48.80% and 59.2%, respectively (2024). Marshall Islands, Micronesia, and Nauru maintain lower levels, reflecting differential impacts of geographical conditions, resource endowments, and policy implementation.

Caribbean region: Belize reached 46.2% high proportion in 2015 but slightly declined by 2024. Trinidad and Tobago has almost no renewable energy deployment, closely related to its economic structure as an oil-producing country.

AIMS region: Mauritius improved from 21.7% to 32.1%, performing most prominently. Cape Verde and Comoros also showed significant growth. Bahrain and Timor-Leste have almost zero renewable energy proportions, reflecting insufficient transition motivation in oil-rich countries.

3.3. SIDS’ Resilience Financing Situation

Figure 6 demonstrates the resilience financing trends flowing to SIDS during the period 2013–2021, providing a visual representation of the levels of international public and private financing (including philanthropic funding) directed toward SIDS [29]. The resilience financing discussed in this context encompasses all concessional and non-concessional financial flows that are specifically designed to reduce climate and disaster vulnerability while enhancing the overall resilience capacity of SIDS. The data shows that while financing commitments during this period showed growth trends, they remain significantly below what is needed to address climate change. From financing composition analysis, although adaptation-related financing (orange portions in the figure) shows certain growth, substantial gaps remain from SIDS’ needs. In 2022, SIDS received only USD 1.5 billion in adaptation funds, accounting for less than 2% of global adaptation financing that year, but small island developing states need USD 12 billion annually to adapt to climate change [30]. Such financing scales are obviously insufficient to support SIDS in addressing multiple severe climate risks, including sea level rise, increased frequency of extreme weather events, and related infrastructure vulnerabilities. Simultaneously, energy-related mitigation financing (yellow portions in the figure) proportions are relatively limited, directly constraining SIDS’ capacity and speed for renewable energy transitions. Statistics from OECD indicate that during 2015–2023, marine renewable energy investments flowing to SIDS countries accounted for only 1.2% of global similar investments, totaling less than USD 1 billion.

Significant gaps typically exist between committed financing and actual funding, making actual situations potentially more severe [31]. This enormous funding gap not only threatens SIDS’ sustainable development pathways but also seriously weakens these countries’ capacity to address increasingly severe climate change impacts, delaying SIDS’ achievement of SDG 7 and SDG 13. Therefore, closing this funding gap should become a priority for international climate finance framework reforms to ensure resource allocation matches vulnerability levels.

3.4. Relevant International Legal Frameworks

3.4.1. The UNCLOS

The exclusive economic zone rights framework established under Article 56 of UNCLOS provides the legal foundation for SIDS to develop marine renewable energy projects [32]. Articles 192–194 create a legal balance between rights and obligations, stipulating that marine resource development must consider environmental impacts while ensuring that environmental protection does not wholly exclude development rights [33]. Article 206 establishes environmental impact assessment obligations as a crucial procedural mechanism, requiring evaluation of potential environmental impacts from development activities [34]. This provision facilitates timely and effective environmental risk control while enabling other states to obtain information regarding potential hazards.

Despite the UNCLOS providing a foundational legal framework, significant gaps exist between domestic legislation in most SIDS and the UNCLOS framework. These states lack comprehensive marine spatial planning legal systems, with ocean management often relying on fragmented sectoral regulations.

3.4.2. Paris Agreement

The Paris Agreement promotes SIDS’ energy transition target-setting through the Nationally Determined Contributions (NDCs) mechanism, yet its non-binding character and inadequate financial mechanisms limit practical effectiveness. While the 1.5 °C target under Article 2 [35] responds to SIDS’ climate vulnerability, the autonomous nature of NDCs results in inconsistent commitment levels across SIDS, as demonstrated in Table 3. Article 6, international cooperation mechanisms [36], and Article 9, financial support provisions [37], theoretically provide a supportive framework for SIDS, but significant supply–demand imbalances persist in practice. Although the Green Climate Fund provides financing for SIDS, complex application procedures and stringent conditionalities prevent most small island states from effectively utilizing available resources.

The Paris Agreement’s “bottom-up” governance model [38] respects national sovereignty but creates fundamental obstacles to energy transition for SIDS that heavily depend on external support for technology and financing. The absence of mandatory international support guarantee mechanisms becomes a critical barrier to energy transformation.

Table 3. SIDS’ conditional and unconditional renewable energy targets in NDCs.

Country	Re Power Target in NDC—Unconditional (MW)	Re Power Target in NDC—Conditional (MW)	Target Year in NDC
Antigua and Barbuda	0	270	2030
Bahamas	475	0	2030
Bahrain	710	0	2035
Barbados	0	606	2030
Belize	0	120	2030
Cabo Verde	235	380	Unconditional by 2030, conditional by 2040
Comoros	None	None	-
Cuba	836	1308	2030
Dominica	0	35	2025
Dominican Republic	0	977	2030
Fiji	133	266	2030
Grenada	0	15	2030
Guinea-Bissau	0	90	2030
Guyana	26	436	2025
Haiti	37.5	162	2030
Jamaica	None	None	-
Kiribati	2.1	3.5	2025
Maldives	None	None	-
Marshall Islands	69	0	2030
Mauritius	863	0	2030
Federated States of Micronesia	None	None	-
Nauru	0	6	2030
Palau	0	24	2025
Papua New Guinea	0	860.1	2030
Saint Kitts and Nevis	35.7	33.1	2030
Saint Lucia	0	72	2025
Saint Vincent and the Grenadines	15	0	2025
Samoa	0	35	2025
São Tomé and Príncipe	0	49	2030
Seychelles	0	11	2030
Singapore	2000	0	2030
Solomon Islands	22.8	45.8	2030
Suriname	209	0	2030
Timor-Leste	0	352	2030
Tonga	0	31	2030
Trinidad and Tobago	None	None	-
Tuvalu	6	0	2020
Vanuatu	0	47	2030

Source: [39].

Table 3. SIDS’ conditional and unconditional renewable energy targets in NDCs.

Country	Re Power Target in NDC—Unconditional (MW)	Re Power Target in NDC—Conditional (MW)	Target Year in NDC
Antigua and Barbuda	0	270	2030
Bahamas	475	0	2030
Bahrain	710	0	2035
Barbados	0	606	2030
Belize	0	120	2030
Cabo Verde	235	380	Unconditional by 2030, conditional by 2040
Comoros	None	None	-
Cuba	836	1308	2030
Dominica	0	35	2025
Dominican Republic	0	977	2030
Fiji	133	266	2030
Grenada	0	15	2030
Guinea-Bissau	0	90	2030
Guyana	26	436	2025
Haiti	37.5	162	2030
Jamaica	None	None	-
Kiribati	2.1	3.5	2025
Maldives	None	None	-
Marshall Islands	69	0	2030
Mauritius	863	0	2030
Federated States of Micronesia	None	None	-
Nauru	0	6	2030
Palau	0	24	2025
Papua New Guinea	0	860.1	2030
Saint Kitts and Nevis	35.7	33.1	2030
Saint Lucia	0	72	2025
Saint Vincent and the Grenadines	15	0	2025
Samoa	0	35	2025
São Tomé and Príncipe	0	49	2030
Seychelles	0	11	2030
Singapore	2000	0	2030
Solomon Islands	22.8	45.8	2030
Suriname	209	0	2030
Timor-Leste	0	352	2030
Tonga	0	31	2030
Trinidad and Tobago	None	None	-
Tuvalu	6	0	2020
Vanuatu	0	47	2030

Source: [39].

3.4.3. Other International Legal Instruments

Regional legal instruments and institutions can provide more operational institutional arrangements tailored to the specific geographical and economic conditions of SIDS.

The Framework for Energy Security and Resilience in the Pacific (FESRIP) 2021–2030 embodies integrated thinking encompassing regional coordination, climate adaptation, and sustainable development [40]. This framework comprehensively addresses key issues including technological challenges, institutional development, and financing, providing unified action guidance for dispersed Pacific Island nations. Similarly, the Caribbean Centre for Renewable Energy and Energy Efficiency (CCREEE) serves as both a “catalyst” and “coordination hub” for Caribbean regional energy transition, promoting renewable energy investment initiatives among SIDS.

However, successful implementation of these regional mechanisms continues to face common challenges including resource constraints, insufficient technical capacity, and coordination complexity. Achieving established visions requires sustained international support, innovative financing mechanisms, and firm governmental commitment.

At the global governance level, the Barbados Programme of Action and the SAMOA Pathway enhance SIDS’ negotiating power in international climate negotiations through coordinated positions and unified action, helping to create synergies with the aforementioned regional cooperation efforts.

4. Discussion

4.1. Analysis of Environmental Challenges of SIDS

SIDS exhibit high exposure and vulnerability to disasters including cyclones, floods, droughts, sea level rise, earthquakes, and tsunamis. The global average rate of sea level rise over the past decade (2013–2022) was more than double that of the first decade of satellite records (1993–2002), posing direct threats to SIDS’ territorial sovereignty, marine rights, and human rights protection [41]. Van Beynen et al. highlighted the unique vulnerability of SIDS due to their geographical isolation, limited resources, and high exposure to environmental risks, proposing a sustainable development measurement index specifically designed for SIDS [42]. However, existing research on SIDS’ environmental vulnerability suffers from common limitations: an excessive focus on describing external climate risks, remaining at the level of status quo diagnosis, and failing to analyze in depth how internal governance structures, resource allocation mechanisms, and socioeconomic institutions systematically undermine environmental resilience.

The fundamental causes of SIDS’ environmental vulnerability are not merely geographical or ecological factors, but essentially the compounded effects of colonial economic legacies and globalization marginalization. SIDS that failed to establish effective environmental governance mechanisms after independence often became trapped in a path dependency of “development priority, environmental compromise”, resulting in structural conflicts between short-term economic gains and long-term ecological stability. For instance, driven by sea level rise, land scarcity, and spatial demands for economic development, the Maldives implemented land reclamation projects that may have “long-term irreversible negative impacts” on the environment and communities, including destruction of coral reefs and seagrass meadows and damage to fisheries and tourism [43]. This endogenous vulnerability undermines the baseline resilience of ecosystems, causing the destructive impacts of external climate shocks to be amplified exponentially. Therefore, understanding SIDS’ environmental challenges requires not only assessing the objective impacts of climate change, but also analyzing the sensitivity and response capacity of their internal institutions to external shocks.

4.2. Energy Transition Challenges of SIDS

As most scholars have noted, SIDS universally face a structural contradiction between abundant renewable energy potential and high dependence on imported fossil fuels [44]. This paper further explores how “energy–climate–development” are interconnected, while also exhibiting inherent tensions among these three elements. SIDS require clean, renewable energy to mitigate climate change, need economic development to support financial investments in climate response, while economic development itself depends on stable and affordable energy supply. In other words, vulnerabilities across economic, environmental, and social dimensions interact and reinforce each other, constituting the systemic challenges facing SIDS’ energy transition.

First, SIDS possess singular economic structures, limited market size, and constrained fiscal budgets. The dispersed characteristics of islands result in the absence of economies of scale in SIDS, elevating the marginal costs of renewable energy technology deployment. This energy structure not only increases the fiscal burden on SIDS’ governments and weakens their resources for enhancing climate change mitigation and adaptation capacity, but also exacerbates coastal erosion and climate risks. Second, SIDS confront environmental challenges, including frequent extreme weather events, sea level rise, and ecosystem degradation, that pose persistent threats to energy infrastructure. Climate risks have multiplier effects on SIDS’ energy systems and economies. Take Hurricane Maria in 2017 as an example. It paralyzed Dominica’s power system and severely damaged public infrastructure, causing losses and damages totaling about USD 1.3 billion, accounting for about 226% of the country’s GDP in 2016 [45]. This transmission chain of “disaster impact–resource crowding–transformation obstruction” shows that the vulnerability of SIDS’ energy systems has nonlinear amplification characteristics, and there is an urgent need to transition to renewable energy and improve energy resilience. Finally, SIDS face social challenges, including brain drain, shortage of technical personnel, and limited educational resources, that directly constrain their capacity for indigenous adaptation and development of renewable energy technologies, as well as absorption of imported technologies [46]. Small population size and scarce professional skills make it difficult for SIDS to establish comprehensive talent pipelines and technical service systems for energy transition.

4.3. Analysis of SIDS’ Financing Dilemmas

The international community has been working hard to help SIDS cope with climate change and transition to renewable energy, conducting negotiations on related issues, formulating treaties, and listing SIDS as priority recipients of assistance. However, financing amounts received by SIDS are disproportionate to the degree of climate change impacts they experience, far insufficient to help SIDS address major challenges of energy transitions and climate change [47]. The amount of funds promised by developed countries has mostly remained verbal or politically motivated. As in the case that developed countries failed to fulfill their commitment to provide USD 100 billion to developing countries annually by 2020, as agreed upon at the 15th Conference of the Parties to the United Nations Framework Convention on Climate Change (UNFCCC, COP15) in 2009, there are many voices of doubt about the USD 300 billion funding target recently proposed at COP29 in 2024 [48].

First, barriers exist to accessing international public funds. International climate finance architectures fail to adequately adapt to SIDS’ special needs. Take the Green Climate Fund (GCF) established under the UNFCCC as an example. Due to the small populations of SIDS, the GCF relies too much on the GDP per capita identification standard, which fails to reflect the multi-dimensional vulnerability of SIDS and cannot accurately capture the development of SIDS, limiting the opportunities of SIDS to obtain international public funds [49] and the amounts that can be obtained. This is also the reason why SIDS call on the international community to consider the MVI index. Additionally, scholars point out that beyond GCF’s complex approval procedures, increasingly financialized financing methods—where developed countries attempt to downplay historical responsibilities and common but differentiated principles, promote loans rather than grants, and advocate using limited public funds to leverage additional private funds—are also unfavorable for SIDS already bearing heavy debt burdens [50].

Second, SIDS face considerable challenges in attracting private investment. Their small market sizes, geographical isolation, and high natural disaster risks significantly increase investment costs and risks. Renewable energy projects typically require large initial capital investments with long payback periods, while SIDS’ limited energy demands make it difficult for investors to achieve economies of scale. In addition, the incomplete regulatory framework and backward grid infrastructure of many SIDS further weaken the confidence of private investment. SIDS may face a more severe climate financing situation under the wave of “carbon unilateralism” triggered by the United States’ re-withdrawal from the Paris Agreement and its impact on global climate finance.

4.4. Inadequacies in Relevant International Institutional Supply

Current core obstacles facing SIDS’ energy transitions include not only technical and financial shortages but also fragmentation and insufficient coordination of relevant international legal institutions. International law fails to provide clear normative guidance for energy transitions, with disconnections between fossil fuel energy production regulation and advancing climate targets [51]. Specifically, the UNCLOS and the Paris Agreement have not formed institutional synergy, disadvantaging SIDS in synergistically achieving SDG 7 and SDG 13.

This first manifests as normative level in-coordination. For example, although the Paris Agreement promotes low-carbon transformation in various countries through NDCs, it has not established institutional links with the marine legal system, resulting in the separation of marine spatial planning and climate action planning. When formulating marine renewable energy strategies, SIDS need to comply with the provisions of the UNCLOS on marine activities and meet the emission reduction requirements of the Paris Agreement, but they cannot obtain integrated legal guidance.

The above in-coordination leads to two key consequences at the practical level. On one hand, marine renewable energy development faces ambiguous legal positioning dilemmas. While the Paris Agreement establishes technology transfer and capacity building frameworks, it fails to create specialized channels for marine energy technologies. On the other hand, dual values of blue carbon ecosystems lack institutional recognition. Mangroves, seagrass beds, and similar ecosystems both serve as important carbon sinks and provide climate adaptation functions, crucial for SIDS. But the Paris Agreement’s carbon sink accounting mechanisms lack coordination with the marine environmental protection provisions of the UNCLOS, preventing SIDS from simultaneously obtaining carbon sink benefits and adaptation support while protecting these ecosystems.

Moreover, the institutional gaps at the domestic implementation level are even more pronounced. The domestic energy legal frameworks of most SIDS lag behind their international commitments, lacking effective mechanisms for integration with international legal frameworks. By contrast, Fiji has achieved relatively successful alignment between international commitments and domestic legislation through its development of a National Energy Policy [52], whereas most SIDS continue to experience fundamental misalignment between policy objectives and legal safeguards. The absence of technical standards, environmental assessment procedures, and investment protection mechanisms further exacerbates implementation difficulties.

In summary, an integrated sustainable development goal, achieving energy transitions and climate resilience, has been artificially divided into scattered responsibilities under different legal systems without corresponding integration mechanisms to promote synergistic achievement.

5. Recommendations

5.1. International Level

5.1.1. Strengthening International Cooperation

First, improving international public fund financing rules: To improve the fairness and effectiveness of climate finance, the following reform measures can be considered: incorporate the MVI into international climate fund allocation decision frameworks, prioritizing climate-vulnerable SIDS’ energy transition issues; simplify climate fund application procedures, establish SIDS special windows, or create dedicated SIDS funds; strengthen supervision mechanisms for developed countries’ climate finance commitment fulfillment. Second, innovative financing methods: Traditional financing tools can no longer meet the huge funding needs brought about by climate change, and innovative financing mechanisms may provide new possibilities for climate-vulnerable countries. For example, Seychelles successfully obtained private financing by swapping blue bonds with debt [53]. According to World Bank assessment reports, this bond not only significantly increased Seychelles’ marine protected area coverage but also created sustainable livelihoods for local fishing communities [54]. The success key of this model lies in combining debt conversion, concessional loans, and market mechanisms, reducing investment risks [55]. Third, strengthening bilateral and multilateral renewable energy technology cooperation: Through international technology cooperation, help SIDS combine local resources to build renewable energy technologies adapted to island environments.

5.1.2. Integration of International Legal Framework

Existing research has predominantly approached the “de-fossil fuelization” from singular perspectives of global climate governance or international climate treaties or has examined the independent roles of the UNCLOS and the Paris Agreement separately. However, in-depth analysis of the synergistic mechanisms between these two legal frameworks remains insufficient. Scholars such as Harro van Asselt emphasize that reducing fossil fuels and advancing energy transitions require support from international cooperation and international legal frameworks, with sustainable development goals also playing a contributory role that can indirectly influence domestic policies and legislation [56,57]. Building upon these studies, this paper undertakes a more detailed examination of energy transition pathways specifically for SIDS.

As a critical intersection of international maritime law and international climate law, SIDS simultaneously confront the threat of sea level rise while urgently requiring advancement in energy transition. Exploring governance innovations at the intersection of ocean law and climate law will help provide a more effective international support framework for SIDS, promote the achievement of SDG 7 and SDG 13, and balance the right to development and environmental protection.

On the one hand, international climate laws such as the Paris Agreement pay little attention to energy transition, oceans, and climate change—the Paris Agreement only mentions marine ecosystem protection in its preamble—but they can provide normative guidance for protecting the marine ecological environment and biodiversity, and they indirectly support Article 192 of the UNCLOS [58]. On the other hand, although the UNCLOS does not explicitly mention climate change, climate change is undoubtedly one of the causes of marine environmental problems such as ocean acidification and coral reef bleaching [59].

As shown in

Table 4. Synergies between the Paris Agreement and the UNCLOS.

Legal Framework	Key Provisions	Significance for SIDS’ Energy Transition
Paris Agreement	Articles 9, 10, and 14	Provides funding and technical support for renewable energy projects
UNCLOS	Article 192	Establishes environmental protection baselines for marine energy development
	Article 194	Balances energy development with ecological environmental protection

, effective integration of renewable energy regulation rules potentially applicable in the Paris Agreement and UNCLOS could provide normative guidance for synergistic achievement of SDG 7 and 13. For example, strengthening and advancing renewable energy targets in NDCs, clarifying timelines and roadmaps, demonstrating political determination and boosting international cooperation confidence [60]; refining assistance rules for climate finance and technology in the Paris Agreement, reducing barriers to financial and technical assistance; strictly implementing environmental impact assessments in SIDS’ marine renewable energy projects, incorporating UNCLOS environmental protection principles into entire energy development processes, protecting coral reefs, mangroves, and other key marine ecosystems.

Additionally, the advisory opinion issued by the International Tribunal for the Law of the Sea on 21 May 2024 responds to national obligations regarding climate change within the UNCLOS framework, indicating inherent connections between marine environmental protection and climate change responses, potentially creating interactions between marine environmental protection obligations and climate targets, enhancing legal binding force of climate actions [61].

The synergy between the Paris Agreement and the UNCLOS will help shape the public values and normative expectations of the international community, create a more just and safer environment for emission reduction and development for SIDS, and help solve the complex dilemma of climate change, energy transition and environmental protection faced by SIDS.

5.2. Domestic Level

5.2.1. Optimizing the Development and Deployment of Marine Renewable Energy

Special geographical positions limit SIDS’ economic development and increase climate change exposure while also providing excellent potential for renewable energy development. Through strategic spatial planning, SIDS can fully utilize abundant marine energy resources, focusing on promoting emission reductions and decarbonization in high-carbon sectors like electricity and transportation. Cape Verde, as a typical SIDS representative in Africa, has achieved significant results in comprehensive utilization of wind and marine energy. Its Cabeólica wind farm project has total installed capacity of 25.5 MW, with wind energy currently accounting for 25% of the country’s electricity structure [62].

Another area worth noting is the floating solar power (FPV) system, which has relatively mature technology and low cost, and is an optimized use of marine space resources. It can form a complementary development system with traditional marine energy (wave energy, tidal energy).

5.2.2. Constructing Sustainable Investment Ecosystems

Stable and transparent domestic investment environments are prerequisites for attracting external funds. SIDS should focus on constructing supportive regulatory frameworks and service systems, formulating standardized and consistent project approval rules, strengthening relevant infrastructure construction, improving energy utilization efficiency, and enhancing investment attractiveness [63,64].

For example, Mauritius has enhanced investor confidence through ambitious renewable energy strategies and targets, focusing on developing green energy industries, and provided a series of preferential tax and financial incentive policies for investors, particularly targeting marine energy and renewable energy investments, optimizing investment environments [65].

5.2.3. Strengthening Environmental Scientific Research and Local Data Governance

Environmental science research and local data accumulation are core tools for SIDS to unleash the potential of renewable energy, avoid ecological risks, and attract sustainable investment. Complete and reliable environmental data systems can produce triple benefits: first, visualizing project economic benefits and ecological impacts to residents, reducing social resistance; second, supporting transparent environmental impact assessment (EIA) processes, improving project approval efficiency; third, helping SIDS quantify the carbon sink capacities of blue carbon systems like mangroves and seagrass beds, forming offset mechanisms with renewable energy project carbon emissions, enhancing overall project sustainability [66]. SIDS generally have low statistical capacities. In the future, SIDS can leverage environmental international organizations and regional cooperation mechanisms, focusing on strengthening environmental scientific research and local data governance [67].

6. Conclusions

Moving beyond vulnerability descriptions, this paper systematically analyzes the structural challenges and solutions faced by SIDS in achieving SDG7 and SDG13 from an interdisciplinary perspective.

SIDS have fragile ecological and environmental systems, a lack of diversification in economic development, and low resilience, and they are extremely vulnerable to climate change. They face the triple challenge of “energy–climate–development”. Climate vulnerability requires SIDS to accelerate the process of energy decarbonization; economic development demands prompt them to pursue energy security and affordability; energy system transformation requires a large amount of capital investment and technical support. However, international climate financing is seriously mismatched with the degree of SIDS’ vulnerability. These multiple constraints form self-reinforcing circular systems for SIDS’ existing development pathways, hindering SIDS’ synergistic achievement of SDG 7 and SDG 13.

Although international legal frameworks including the UNCLOS and the Paris Agreement provide certain support for SIDS, they suffer from normative separation and insufficient coordination, failing to form effective institutional synergy, resulting in insufficient legal foundations for marine renewable energy development and hindering SIDS’ energy transition processes.

This study proposes the following recommendations:

At the international level, suggestions are made across three dimensions: first, improving international public fund financing rules by incorporating the MVI into resource allocation decision frameworks; second, innovating financing models by promoting mechanisms like “debt-for-nature swaps”; third, integrating relevant provisions of the UNCLOS and the Paris Agreement to construct unified legal frameworks for marine energy development.

At the domestic level, SIDS should focus on constructing supportive policy systems: optimizing the development and deployment of marine renewable energy; constructing sustainable investment ecosystems through legislation and policy support to reduce investment risks; strengthening environmental scientific research and local data governance.

In conclusion, climate change, energy transitions, and international legal frameworks constitute an inseparable triangular relationship. SIDS’ environmental vulnerability should be viewed as a multi-level, cross-regional, complex, systemic challenge requiring multi-dimensional coordination across legal, technical, economic, and environmental spheres. Beyond legal frameworks, non-legal factors including political will, capacity-building, and socio-cultural dynamics exert significant influence on energy transition processes in SIDS. These factors frequently determine the effectiveness and sustainability of policy implementation. Through strengthening international institutional synergy and multi-level energy governance and by fully considering the specific national circumstances and socio-cultural backgrounds of individual countries, SIDS have prospects for constructing resilient energy systems and achieving SDG 7 and SDG13.