Policy Analysis of Environmental Governance in the Bohai Rim Region (2001–2021)—A Perspective Based on the Vertical Synergy of Policies

Abstract

This study utilized policy text quantification, the entropy weighting technique, and the standard setting of the vertical policy synergetic degree to measure the synergy status of the environmental protection and governance policies in the Bohai Rim Region horizontal space (2001–2021). The standard setting of the vertical policy synergetic degree encompasses three dimensions, namely the policy subjects, policy objectives, and policy instruments. A comprehensive text database was established to facilitate analysis with 122 pieces of Bohai Sea environmental governance policies. After policy text quantification, this research found that the weight coefficients of the three indicators of policy subjects, policy instruments, and policy objectives were slightly different. This study found that provinces should balance the roles of policy issuers, the selection of policy instruments, and the setting of objectives to enhance compatibility between local and central governance policies; the vertical synergy of policies is closely related to the scientific nature of policy formulation. The incompleteness of the vertical synergy of policies affects the effectiveness of Bohai Sea environmental governance. In the future, the Bohai Rim Region’s environmental governance should continue to deepen the synergy of policies, strengthen scientific governance, promote regional linkage, and improve the scientificity of the policy system.

1. Introduction

The white paper “Marine Eco-Environmental Protection in China”—issued by the State Council Information Office of the People’s Republic of China [1] in July 2024—emphasized that China is a firm promoter and active actor in protecting the marine eco-environment. The paper has given priority to eco-environmental conservation and pursued systematic governance. The Bohai Sea is a key marine ecological and environmental management area. It is a semi-enclosed, prominent strategic position with a unique natural ecology and limited water exchange and self-purification capacity. It is also an important sea area supporting the economic and social development of the Beijing–Tianjin–Hebei region and the national energy strategy.

In 2001, the Bohai Blue Sea Action Plan was approved by the State Council, initiating the Bohai Sea pollution control action. Also, in 2021, the three-year ecological restoration campaign for the comprehensive management of the Bohai Sea successfully concluded with the core objectives of several high-quality tasks. The Circum-Bohai Sea Region (encompassing Tianjin Municipality, Liaoning Province, Shandong Province, and Hebei Province) includes 12 cities (Dalian, Yingkou, Panjin, Jinzhou, Huludao, Qinhuangdao, Tangshan, Cangzhou, Binzhou, Dongying, Weifang, and Yantai) and 1 municipality (Tianjin); these make up the “1 + 12” coastal cities. Shandong, Liaoning, Hebei, and Tianjin have issued policy documents to guide the regional comprehensive governance of the Bohai Sea and improve the efficiency of coordinated management work in the Bohai Sea environment. The vertical synergy of policies can reflect the degree of importance attached to Bohai Sea’s comprehensive governance by different provinces and the scientific and rational nature of policy formulation.

The formulation of policies related to Bohai Sea environmental governance can effectively guide the development of the latter. However, due to the conflict and uncertainty in the policy, the policy’s failure is inevitable. The consideration of the vertical synergy of the introduction of the policies of Bohai Sea provinces and cities is important for understanding the central government’s policy and for the Circum-Bohai Sea Region. It is important to understand the proliferation of and improvement in the Bohai Sea environmental governance policy documents issued by the central government [2].

Policy synergy at different levels can produce the effect of 1 + 1 > 2 [3], is conducive to the promotion of the advanced experience of each region, and harnesses the enthusiasm of local governments [4]. Therefore, the exploration of environmental governance in the Bohai Sea region should also pay attention to the vertical synergy between the Bohai Sea environmental governance policies of different provinces and municipalities around the Bohai Sea and the central policy and then summarize the general rule of policymaking and advanced experience, as well as analyzing the effects of policymaking and environmental governance in the Bohai Sea. The potential connection between policy formulation and the effect of Bohai environmental governance should be analyzed.

The purpose of this article is to discuss the policies in the circum-Bohai region in terms of environmental protection and enrich the empirical research on vertical policy synergy with indicators and real-world data. Additionally, leveraging text mining to analyze policy documents, assess vertical synergy, and evaluate vertical policy synergy in real time is valuable in developing governance models tailored to the Bohai Rim region to enhance policy implementation and provide a basis for continuous improvement.

The research questions raised in this study are as follows: What are the similarities and differences in the vertical synergy of the Bohai Sea environmental governance policies in the Bohai Rim region (encompassing Tianjin Municipality, Liaoning Province, Shandong Province, and Hebei Province)? Does the vertical policy synergy of comprehensive Bohai Sea environmental remediation in the Bohai Rim region directly impact the actual governance effect?

In order to address these questions, this study explored the following research ideas: i. determining an evaluation index system; ii. designing scoring criteria; iii. scoring and assigning values; and iv. analyzing the data, conducting a comparative analysis of the Bohai Rim region, and drawing conclusions.

To address these questions, the remainder of this article is organized as follows: Section 2 introduces the existing empirical studies related to vertical policy synergy. Section 3 presents the methodology of this research, including the policy text quantification method, data analysis method, research framework, and data collection. Section 4 introduces the results of the three-index analysis of policy vertical synergy. Section 5 focuses on analyzing environmental governance effectiveness in the Bohai Rim region. Section 6 comprises the conclusion and discussion of this research.

2. Literature Review

2.1. Theoretical Framework for Vertical Policy Synergy

Policy synergy is a theory that emerged in the West on the basis of “policy management” and “holistic government”. It is a way for different institutional levels of government to make their public policies compatible, coordinated, and mutually supportive through communication and dialog in order to solve complex problems and achieve common goals [5]. Policy synergy refers to the consistency between two or more policy procedures [6]; it can be understood as the harmonization, coordination, and cooperation of mutually reinforcing policies through the achievement of synergies or the creation of positive interactions between policy objectives or actions (both horizontally and vertically) across scales and sectors within a given governance context [7,8,9,10]. It also emphasizes that, under the premise of common policy goals, different departments, and institutional multi-level governments can cooperate and support each other from policy formulation to policy implementation. Policy synergy can be divided into horizontal and vertical dimensions, and also includes the time dimension synergy of the same type of policy [11].

Studies on vertical policy synergy are closely connected with multi-level governance (MLG) and collaborative governance theory. The purpose of collaborative governance is to manage relationships and take action on common problems [12], an important premise of which is that it is difficult for individuals or organizations to accomplish a task independently, and that there are three key elements: solving a common problem as a common goal, cooperation among multiple actors, and a consensus on values [13,14]. Vertical policy synergy considers questions of alignment between levels of governance [10] and is concerned with linking national and sub-national levels to guarantee the joined-up and sustainable implementation and management of inclusive policies, as well as interactions between policy implementers and policymakers that result in policy decisions [15]. These synergy mechanisms traditionally focus on the work of governmental institutions. Effective vertical policy synergy between the policymakers at the “top” and the implementers at the “bottom” is important for successful policy design and policy implementation that result in effective and practical policy decisions [15] Autonomy, far-reaching discretion, and the orchestration of different institutional levels of government with actors are needed to prevent policy failure [16,17,18].

Research on vertical policy synergy has transitioned from the description of the latter to complex research methods for evaluating its effects [19,20]. In terms of the design of the research dimensions, the studies on vertical policy synergy focus on assessing synergy’s effects, synergy path analysis, and synergistic incentive research. Even though vertical policy synergy is an important current research hotspot that is reflected in policy coordination and cooperation, there are insufficient empirical studies on vertical policy synergy that have sufficient data and well-designed research methods. In addition, the measurement indicators in the existing studies are too limited to fully capture the complexities of policy vertical coordination. The existing political science and public administration literature primarily focuses on discussing the pros, cons, and types of policy instruments [21], having little to say about how policy vertical synergy assists with evaluating policy conduction in specific regions like the Bohai Sea.

2.2. Empirical Studies on Vertical Policy Synergy in the Bohai Sea Region

The marine environmental problems in the Bohai Sea mainly include the eutrophication of nearshore water bodies, land-based pollution, etc. [22]. Relevant studies are more concerned with the Bohai Sea’s environmental governance issues due to the lack of an effective governance model plus the impact of human activities; the Bohai Sea’s ecosystem health, fishery water environment, and other indicators are lower than the averages in China [23].

The existing Bohai Sea environment-related policy studies differ in their research content, research dimensions, research methodology, and other aspects. The scientific community has provided a wide variety of content regarding Bohai Sea environmental policy research to help solve the marine problem: comprehensive management measures for the Bohai Sea’s ecological environment [24,25]; institutional research, e.g., research on marine ecological and environmental liability insurance systems [26,27]; research on the pollution management model [28]; and policy research [29].

Several empirical studies have examined the application of vertical policy synergy in the Bohai Region. Pan et al. (2023) [21] quantitatively analyzed Bohai Sea environmental governance policies from 1996 to 2022, revealing a shift from command-and-control instruments to mixed policy instruments, reflecting improved vertical synergy. There were researchers evaluated the synergy of coastal ocean pollution prevention policies in China, identifying significant gaps in vertical coordination within the Bohai Sea region [20]. As well as examined the vertical coordination challenges in Bohai Sea reclamation ecological compensation policies, highlighting the need for better alignment between central and local governments [24]. Existing studies also evaluated the sustainable development of the Bohai Sea Rim, emphasizing the importance of vertical synergy in achieving integrated land–sea management [25] and assessed the value of marine ecosystem services in the Bohai Sea, underscoring the role of vertical policy coordination in marine resource management [26]. Despite progress, several challenges hinder effective vertical policy synergy in the Bohai Sea region, such as misaligned policy goals [11], inadequate information sharing [12] and uneven resource allocation [9].

There are several existing studies utilizing various methods to evaluate policy synergy. For example, one study proposed a model of synergy between urban greening and local planning according to a case study [30], one study used a difference-in-difference approach to evaluate the synergy of the Comprehensive Demonstration Cities of Energy Conservation and Emission Reduction Fiscal Policy for pollution and carbon reduction [31], and a policy text quantification method to evaluate policy vertical and horizontal synergy was proposed [21]. The policy text quantification method is a popular method for evaluating policy synergy; it was utilized to evaluate the regional coordination of the Beijing–Tianjin–Hebei region in China [32,33].

In conclusion, vertical policy synergy plays a crucial role in promoting regional integration and sustainable development in the Bohai Region [20,21]. By analyzing existing research and policy documents, this review has identified key factors that contribute to successful vertical policy synergy, as well as challenges and opportunities for future policy design and implementation. To develop governance models tailored to the Bohai Sea region to enhance policy implementation, text mining could be leveraged to analyze policy documents and assess and evaluate vertical policy synergy in real time, providing a basis for continuous improvement.

3. Methods

3.1. Policy Text Quantification Method

According to the theory of policy synergy, the policy synergy of Bohai Sea environmental governance is reflected in three aspects: the vertical policy synergy process following the superior national strategy, the horizontal synergy between different provincial governments as well as departments within the province, and the temporal synergy between the policy introduction and the central policy introduction [11]. Drawing on existing research, this study started from the perspective of vertical policy synergy, focusing on the synergy between the Bohai environmental governance policies of Shandong, Liaoning, Hebei, and Tianjin, and the central policy text, to analyze the characteristics, experiences, and shortcomings of the policy’s introduction in circum-Bohai provinces and, furthermore, put forward policy recommendations.

This study adopted the text analysis method and entropy power method, for circum-Bohai Sea provinces, to analyze the policies related to Bohai Sea environmental governance, drawing on the existing policy synergy research to construct the “policy subject–policy objectives–policy instruments” trinity analysis research framework, as shown in

Table 1. Vertical policy synergy evaluation criteria.

Policy subjects	Subject synergy	Measures the level of importance local governments attach to Bohai Sea policies [34].
Policy objective	Objective synergy	Evaluates the clarity, specificity, and alignment of local and central policy goals [35]
Policy instruments	Instrument synergy	Assesses the clarity, specificity, and appropriateness of policy tools and measures [36].

. The main body of the text describes the importance of different institutional levels of government for the Bohai Sea’s environment; the policy objectives relate to the importance and focus of different governments regarding the foundation of Bohai Sea governance; the policy instruments relate to the orientation of different levels and different local governments’ thinking and personality characteristics in the formulation and implementation of policies, which determine whether or not the policy objectives can be realized. In order to assess the synergy between the central and local governments in the environmental governance policy in the Bohai Rim Region, a scientific and reasonable scoring evaluation system can be established to assess the vertical synergy between the Bohai Rim Region and the central Bohai Sea environmental governance policy, with the following evaluation indicators:

The scoring criteria were derived from normative documents such as the Interim Measures for the Management of National-level Special Programs and Interim Measures for the Management of Provincial-level Special Programs, as well as through iterative readings and categorizations of policy texts. The scoring system is detailed below in

Table 2. General scoring criteria.

Score	Indicator	Detailed Explanation
5	Subject synergy	Issued by the provincial people’s government; jointly issued by the provincial people’s government and the central government.
4		Jointly issued by the Provincial Development and Reform Commission and various departments (bureaus).
3		Issued by the Provincial Development and Reform Commission; jointly issued by various departments (bureaus); forwarded by the provincial government; response from various departments (bureaus) to proposals from the People’s Congress.
2		Issued by various departments (bureaus).
1		Issued by the offices of various departments; issued by specialized offices, groups, and other such agencies; issued by various prefecture-level cities.
5	Objective synergy	Clearly propose that the development goals should adhere to serving the overall objective of Bohai Sea governance: pollution control, ecological protection, and risk prevention; clearly specify the name of the central document to be followed; clearly establish goals in accordance with the overall planning for the marine functional zoning of the three provinces and one municipality as outlined by the central government (China’s marine functional zones are categorized into eight types: agriculture and fishery, port and shipping, industrial and urban sea use, minerals and energy, tourism and recreation, marine protection, special use, and reserved areas); explicitly state the intention to collaborate with the central government or relevant departments within the province (or municipality), or to work in accordance with central government documents to meet certain standards; dedicate a specific chapter to the relevant content, with clear exposition, quantitative indicators, or specific operational methods; clearly specify the names of national projects or funding programs; demonstrate synergy among specific provincial departments resulting from alignment and synergy with central government policies; fulfill 5 or more of the above conditions.
4		Fulfill 4 of the above conditions.
3		Fulfill 3 of the above conditions.
2		Fulfill 2 or 1 of the above conditions.
1		Fulfill none of the above conditions.
5	Instrument synergy	There is a specific and feasible project for the environmental governance or protection of the Bohai Sea, with operational details; there is a clear division of implementation responsibilities and public disclosure of personnel information; the planning project involves aspects such as pollution control, ecological protection, or risk prevention; there are specific implementation pathways and safeguarding measures, including measures and instruments such as allocated funds, regulatory controls, emission reduction subsidies, pollution taxes, and pollution standards; expressions indicating synergy in response to policies or measures from higher-level governments are present; there are practical and feasible policy suggestions or future plans; there are specifically broken-down project indicators; a dedicated chapter is established for the relevant content, with clear exposition and quantitative indicators; fulfill 5 or more of the above conditions.
4		Fulfill 4 of the above conditions.
3		Fulfill 3 of the above conditions.
2		Fulfill 2 or 1 of the above conditions.
1		Fulfill none of the above conditions.

Note: The indicator score is the average score of the indicator in a certain province, which is the ratio of the total score of subject collaboration to the number of policies.

:

The State Council’s policy documents on marine functional zoning for Shandong, Hebei, Liaoning, and Tianjin outline specific objectives, including reclamation control, mariculture zones, marine protected areas, and coastline restoration. These objectives align with broader central goals categorized into pollution control, ecological protection, and risk prevention. The synergy of objectives between local and central policies is a critical measure of vertical alignment.

Following the establishment of quantitative criteria, the study proceeded with a three-stage scoring process: pre-scoring, preliminary scoring, and final expert scoring. Detailed information is shown in

Table 3. The three-stage scoring protocol.

The Three-Stage Scoring Protocol	Sequential Refinement
Pre-scoring calibration	Involved independent coding by 2 trained researchers using a standardized rubric to assess 20% of randomly sampled policies. Inter-coder reliability was established via Cohen’s Kappa coefficient (κ = 0.81), resolving discrepancies through consensus-building sessions. This stage focused on rubric validation rather than final scoring.
Preliminary scoring	Applied the validated rubric systematically across all 122 policy texts, with dual-blind coding by two separate analyst teams. Automated text analysis (LDA topic modeling) complemented manual scoring to detect latent coordination patterns. Divergent cases (<15%) underwent third-party adjudication by senior researchers.
Expert validation	Employed purposive sampling of 6 domain specialists: 2 government officials involved in Beijing–Tianjin–Hebei coordination offices, 2 academic experts with ≥5 years’ regional policy research, and 2 trained researchers in universities.

.

A modified Delphi process ensured iterative feedback, achieving a content validity index (CVI) > 0.9 through two-round scoring and rationale documentation. This tripartite structure ensured progressive rigor—moving from instrument validation to comprehensive application and external verification—while addressing the reliability–validity trade-off inherent in policy text analysis. The expert scores were standardized to calculate a composite index of vertical synergy using the entropy weight method.

The composite index is expressed as follows:

The Vertical Synergy Comprehensive Evaluation index $\left(Y\right)=w_1\times X_1\left(\mathrm{S}\mathrm{u}\mathrm{b}\mathrm{j}\mathrm{e}\mathrm{c}\mathrm{t} \mathrm{S}\mathrm{y}\mathrm{n}\mathrm{e}\mathrm{r}\mathrm{g}\mathrm{y}\right)+w_2\times X_2\left(\mathrm{O}bjective \mathrm{S}\mathrm{y}\mathrm{n}\mathrm{e}\mathrm{r}\mathrm{g}\mathrm{y}\right)+w_3\times X_3\left(Instruments \mathrm{S}\mathrm{y}\mathrm{n}\mathrm{e}\mathrm{r}\mathrm{g}\mathrm{y}\right)$

$w_1, w_2{, w}_3$ are the weight coefficients of each index, respectively; X₁ is the average score for subject synergy in Bohai environmental governance policy texts, X₂ is the average score for objective synergy in Bohai environmental governance policy texts and instruments synergy, and X₃ is the average score for the instrument synergy index.

By systematically evaluating vertical policy synergy, this study aimed to contribute to the optimization of Bohai Sea environmental governance and inform future policy formulation and implementation.

3.2. Entropy Weight Method

The textual analysis method for policy synergy is actually based on certain quantitative standards for scoring policies. This study explored the synergy between the Bohai Rim Region’s environmental policy and the central policy based on the scoring standards, according to the first four quantitative indicators, to further construct the entropy weight method to determine the weights of the vertical policy synergy comprehensive evaluation index, the basic structure of which is as follows:

For the different synergy data of the Bohai Rim Region, the data need to be dimensionless in the calculation process because synergy values of different natures will have a large impact on the results.

When evaluating using the entropy weight method, the greater the degree of data change in the sample, the smaller the information entropy, the more the information that will be provided, the greater the importance of the feedback, and the greater the weight value.

Firstly, the data are standardized to obtain the matrix B. According to Formula (1), the weight of the jth sample under the ith indicator is calculated as P_ij:

$$P={\displaystyle \frac{\mathrm{y}\mathrm{i}\mathrm{j}}{{\sum }_{i=1}^n\mathrm{y}\mathrm{i}\mathrm{j}}},\mathrm{i}=1,\dots ,\mathrm{n}$$

(1)

Next, the entropy value e_j of the ith indicator is calculated according to Equation (2).

$$e_j=-{\displaystyle \frac{1}{lnn}}\sum _{i=1}^n{P}_{ij}\ln P_{ij}$$

(2)

Then, the coefficient of variation d_j for each indicator is calculated according to Equation (3):

$$d_j=1-e_j$$

(3)

Finally, the entropy method weight w_j of the ith indicator is calculated according to Equation (4):

$$w_j={\displaystyle \frac{\mathrm{g}\mathrm{j}}{{\sum }_{i=1}^n\mathrm{g}\mathrm{j}}}$$

(4)

The entropy value, difference coefficient, and weight of evaluation indicators at all levels were calculated according to the above steps. The entropy value method weights of the indicator system of the subject synergy, tool system, and goal synergy of the Bohai Rim Region were finally derived.

3.3. Research Framework

On the basis of existing research, this study constructed a four-pronged policy analysis framework of “policy time–policy subject–policy objective–policy tool” to assess the vertical synergy between the Bohai Sea environmental governance policies of the three Bohai provinces and one city and the central government’s policy of dividing the Bohai Sea into functional zones. The vertical synergy between the Bohai environmental governance policies of the Bohai Rim Region and the central government’s policies on environmental governance and functional zone division was evaluated. The analytical framework shown in Figure 1 was constructed:

3.4. Data Collection

The regional scope studied in this work is the Bohai Rim Region, and the literature collection and organization was based on the following principles:

This study adopted a systematic approach to data collection and analysis, focusing on policy documents related to the environmental governance of the Bohai Sea. The temporal scope of the research spans from 1 October 2001, marking the State Council’s approval of the Bohai Sea Action Plan by the Environmental Protection Administration, to 31 December 2021, which coincides with the conclusion of the three-year Bohai Sea Comprehensive Treatment Campaign.

The data collection process was conducted in three stages. First, using “Bohai Sea” as the primary keyword, we systematically screened departmental regulations and national normative documents pertaining to the environmental management of the Bohai Sea. This was accomplished by searching authoritative platforms, including the official website of the Chinese government, the Ministry of Natural Resources, the National Development and Reform Commission, and the Peking University Faber database.

Second, we expanded the search to include policy documents at the provincial and municipal levels. Using “Bohai” as the keyword, we examined the official websites of the provincial governments of the three provinces (Shandong, Liaoning, and Hebei) and one municipality (Tianjin) directly bordering the Bohai Sea, as well as the Peking University Faber database. Additionally, we conducted a targeted search of the official websites of the “12 + 1” coastal cities within the Bohai Rim region to identify relevant local policy documents.

Third, the scope of data collection encompassed policies and regulations formulated by both central and local legislative and administrative bodies. The selection criteria prioritized policy instruments such as laws, regulations, plans, decisions, opinions, measures, rules, and notices.

As of 31 December 2021, a total of 122 policy documents related to the environmental governance of the Bohai Sea, issued between 2001 and 2021, were identified and included in the final dataset. These documents were categorized as follows: 24 from the central government, 32 from Shandong Province, 35 from Liaoning Province, 16 from Tianjin Municipality, and 15 from Hebei Province. A comprehensive text database was established to facilitate analysis.

The concept of vertical policy synergy examined in this study specifically refers to the alignment and coordination between provincial and municipal policies within the three provinces and one municipality, as well as their integration with 12 key central policy texts. Particular emphasis is placed on the synergy between the Action Plan for the Comprehensive Treatment of the Bohai Sea, the Action Plan for the Prevention and Control of Water Pollution, and the State Council’s Document on Functional Zoning of the Four Provinces and Municipalities. Consequently, the temporal dimension of the analysis was confined to policy texts issued between 2001 and 31 December 2021.

4. Results

4.1. Analysis of Vertical Synergy Index

In order to ensure the rigor of the index weights, this study formed a group of experts to score the subject synergy, goal synergy, and tool synergy of the Bohai environmental governance policy texts of the Bohai Rim Region in a two-by-two comparison according to the scoring system mentioned above.

Through pre-scoring, preliminary scoring, and final scoring by experts, the average scores of subject synergy, objective synergy, and instrument synergy for the Bohai environmental governance policy texts of the circum-Bohai Sea region shown in

Table 4. Average scores ($X_i$) for subject synergy, objective synergy, and instrument synergy in Bohai environmental governance policy texts.

	${\mathit{X}}_1$ (Subject Synergy)	${\mathit{X}}_2$ (Objective Synergy)	${\mathit{X}}_3$(Instrument Synergy)
Shandong	3.16	3.44	4.16
Liaoning	2.73	3.97	4
Hebei	2.47	3	3.73
Tianjin	3.19	3.75	4.19

were determined:

Following the scoring of policies across the three provinces and one municipality based on the established index system, this study employed the entropy method to calculate the entropy values and weight coefficients for the comprehensive evaluation index of vertical synergy in Bohai environmental policies. As shown in

Table 5. Entropy weight calculation results.

Index	Subject Synergy	Objective Synergy	Instrument Synergy
ej	0.111	0.108	0.111
dj	0.889	0.892	0.889
wj	0.333	0.334	0.333

, the entropy weights for the corresponding coefficients, ranked from smallest to largest, are as follows: w₁ = 0.333 (subject synergy), w₂ = 0.334 (objective synergy), and w₃ = 0.333 (instrument synergy). This indicates that objective synergy exerts a slightly greater influence on the evaluation of vertical policy synergy coefficients compared to the other two dimensions. However, the marginal differences in entropy weights among the three indices suggest that their impacts on the overall vertical synergy index are relatively balanced.

The weight coefficients for the three dimensions—subject synergy, objective synergy, and instrument synergy—are nearly equivalent, with values of approximately 33.3%, 33.4%, and 33.3%, respectively. This parity underscores the balanced influence of these indices on the vertical synergy evaluation. Specifically, the alignment of local-level policy texts with central government strategies in the comprehensive environmental remediation of the Bohai Sea is critical. The formulation of detailed objectives in accordance with central government directives, as well as the consistency of policy instruments between local and central documents, plays a pivotal role in enhancing vertical synergy.

The comprehensive evaluation index for vertical synergy is calculated using the following formula:

The Vertical Synergy Comprehensive Evaluation index $\left(Y\right)=w_1\times X_1\left(\mathrm{S}\mathrm{u}\mathrm{b}\mathrm{j}\mathrm{e}\mathrm{c}\mathrm{t} \mathrm{S}\mathrm{y}\mathrm{n}\mathrm{e}\mathrm{r}\mathrm{g}\mathrm{y}\right)+w_2\times X_2\left(\mathrm{O}bjective \mathrm{S}\mathrm{y}\mathrm{n}\mathrm{e}\mathrm{r}\mathrm{g}\mathrm{y}\right)+w_3\times X_3\left(Instruments \mathrm{S}\mathrm{y}\mathrm{n}\mathrm{e}\mathrm{r}\mathrm{g}\mathrm{y}\right)$

w₁ = 0.333 (subject synergy), w₂ = 0.334 (objective synergy), and w₃ = 0.333 (instrument synergy); the minimal variation among these coefficients further confirms the balanced contributions of subject synergy, target synergy, and tool synergy to the overall vertical synergy index.

The calculated vertical synergy indices for the three provinces and one municipality are as follows:

• Y (Shandong Province) = 3.59;
• Y (Liaoning Province) = 3.57;
• Y (Hebei Province) = 3.07;
• Y (Tianjin Municipality) = 3.71.

Ranking the regions from highest to lowest by vertical synergy yields the following order: Tianjin > Shandong Province > Liaoning Province > Hebei Province. This indicates that Tianjin exhibits the highest degree of vertical synergy with central government policy documents in the context of Bohai Sea environmental governance, followed by Liaoning and Shandong provinces. Hebei Province, however, lags significantly behind the other regions.

Notably, the vertical synergy indices for Tianjin, Liaoning, and Shandong are relatively close, suggesting a comparable level of policy alignment with central government directives. In contrast, Hebei Province demonstrates a markedly lower level of vertical synergy, highlighting potential gaps in policy coherence and implementation.

The findings underscore the importance of aligning local policy objectives and instruments with central government strategies to enhance vertical synergy in environmental governance. While Tianjin, Liaoning, and Shandong have achieved relatively high levels of synergy, Hebei Province’s performance indicates a need for targeted interventions to improve policy coherence and integration. These insights provide valuable guidance for policymakers seeking to strengthen the effectiveness of environmental governance frameworks in the Bohai Sea region.

4.2. Subject Synergy Analysis

Based on the expert scoring of policy texts, the subject synergy scores for the three provinces and one municipality, as Figure 2 shows, are as follows: Shandong Province (3.16), Liaoning Province (2.73), Hebei Province (2.47), and Tianjin Municipality (3.19). Ranking these regions from highest to lowest by subject synergy yields the following order: Tianjin > Shandong Province > Liaoning Province > Hebei Province.

The subject synergy metric reflects the degree to which the three provinces and one municipality align their local policies with the central government’s regulations, resolutions, and plans for Bohai Sea governance. This alignment is indicative of the importance these regions place on central directives and their commitment to integrating them into local policy frameworks.

Tianjin Municipality: Tianjin demonstrates the highest level of subject synergy among the regions, with a score of 3.19. This is attributable to the active role of the Tianjin Municipal People’s Government in policy formulation. Of the 16 provincial-level policy documents analyzed, 5 were directly enacted by the Tianjin Municipal People’s Government, while the remaining 11 were issued by municipal departments. This high level of engagement by the municipal government underscores its strong alignment with central government priorities.

Shandong Province: Shandong Province ranks second, with a subject synergy score of 3.16. The province issued a total of 32 documents, with 11 originating from the provincial government and 21 from prefecture- and county-level cities. The relatively lower score can be attributed to the larger volume of documents and the greater number of subordinate administrative units involved in policy formulation. This decentralization, while indicative of broad engagement, may reduce the coherence and alignment of policies with central government directives.

Liaoning Province: Liaoning Province ranks third, with a subject synergy score of 2.73. The provincial government issued 13 documents, while departments and prefecture-level cities issued 21 additional documents. Notably, the Liaoning Provincial Department of Ocean and Fisheries and the Department of Finance played particularly active roles in shaping Bohai Sea environmental policies. This collaborative approach reflects the provincial government’s efforts to delegate responsibilities while maintaining oversight, though the involvement of multiple actors may dilute the overall subject synergy score compared to Tianjin.

Hebei Province: Hebei Province has the lowest subject synergy score (2.47) among the regions. This reflects a comparatively lower level of engagement by the provincial government in issuing policy documents related to Bohai Sea environmental governance. The limited involvement of the provincial government as the primary issuing body may explain the weaker alignment with central government priorities.

The variation in subject synergy scores across the regions highlights the influence of administrative structure and policy issuance patterns on vertical policy alignment. Tianjin’s high score underscores the benefits of centralized policy formulation at the municipal level, which enhances coherence and alignment with central directives. In contrast, the larger number of policy documents and the involvement of multiple administrative units in Liaoning and Shandong provinces, while indicative of broad participation, may lead to fragmented policy implementation and lower subject synergy. Hebei Province’s low score suggests a need for greater provincial-level engagement to improve alignment with central government priorities.

These findings emphasize the importance of administrative coordination and centralized leadership in achieving vertical policy synergy. Policymakers in regions with lower subject synergy scores may consider streamlining policy issuance processes and enhancing the role of provincial governments to improve alignment with central directives.

4.3. Objective Synergy Analysis

The expert-assigned scores for the objective synergy indicators of policy texts across the three provinces and one municipality, as Figure 2 shows, are as follows: Shandong Province (3.44), Liaoning Province (3.97), Hebei Province (3), and Tianjin Municipality (3.75). Ranking these regions from highest to lowest by goal synergy yields the following order: Liaoning Province > Tianjin > Shandong Province > Hebei Province.

Objective synergy is a critical dimension of vertical policy alignment, reflecting the extent to which local policy objectives align with those of the central government. The central government’s Bohai Sea environmental management policies, as outlined in planning documents, emphasize three overarching goals derived from NVIVO V15.0 software-based text analysis: pollution control, ecological protection, and risk regulation. The goal synergy scores of the three provinces and one municipality provide insights into their adherence to these national policy priorities.

Liaoning Province: With the highest goal synergy score (3.97), Liaoning Province demonstrates the strongest alignment with central government objectives. Its policy documents extensively and meticulously reference the central government’s goals, reflecting a comprehensive and detailed approach to policy formulation. This high level of alignment suggests that Liaoning Province has effectively internalized and operationalized the central government’s priorities in its local policies.

Tianjin Municipality: Tianjin ranks second, with a goal synergy score of 3.75. While slightly lower than Liaoning’s, Tianjin’s score still indicates a robust alignment with central government objectives. This reflects the municipality’s proactive efforts to integrate national priorities into its local policy framework, though there may be minor gaps in specificity or comprehensiveness compared to Liaoning.

Shandong Province: Shandong Province’s goal synergy score of 3.44 places it third among the regions. While its policies generally align with central government goals, the lower score suggests room for improvement in the precision and depth of its policy objectives. This may stem from a broader or less detailed articulation of goals in its policy documents.

Hebei Province: Hebei Province has the lowest goal synergy score (3), indicating significant gaps in aligning its policy objectives with those of the central government. This suggests that Hebei’s policy documents may lack the clarity, specificity, or comprehensiveness needed to fully reflect national priorities. The relatively low score highlights the need for improved policy design and implementation to enhance goal alignment.

The variation in goal synergy scores underscores the importance of clearly defined and well-articulated policy objectives in achieving vertical policy alignment. Liaoning Province’s high score exemplifies the benefits of detailed and comprehensive policy formulation that closely mirrors central government priorities. In contrast, Hebei Province’s low score highlights the challenges of ensuring effective policy transmission and implementation at the local level.

These findings suggest that regions with lower goal synergy scores, such as Hebei Province, could benefit from adopting a more structured and detailed approach to policy design. This includes explicitly referencing central government goals, ensuring clarity in policy objectives, and enhancing the coherence of local policies with national priorities. By doing so, these regions can improve their alignment with central directives and contribute more effectively to the broader goals of Bohai Sea environmental governance.

4.4. Instrument Synergy Analysis

The expert-assigned scores for the instrument synergy indicators of policy texts across the three provinces and one municipality, as Figure 2 shows, are as follows: Shandong Province (4.16), Liaoning Province (4), Hebei Province (3.73), and Tianjin Municipality (4.19). Ranking these regions from highest to lowest by instrument synergy yields the following order: Tianjin Municipality > Shandong Province > Liaoning Province > Hebei Province.

Policy instruments represent the mechanisms and tools adopted by local governments to achieve policy objectives. The extent to which these instruments need to align with central government directives remains a subject of debate, as central policy documents often emphasize the need for the localized adaptation of policy measures to suit regional contexts. Nevertheless, the instrument synergy scores provide valuable insights into the alignment of local policy instruments with central government frameworks.

Tianjin Municipality: Tianjin ranks first, with an instrument synergy score of 4.19. While slightly lower than Shandong’s, Tianjin’s score indicates a strong alignment of policy instruments with central government priorities. The municipality’s policy texts reflect a balanced approach, combining central directives with localized adaptations to address regional challenges.

Shandong Province: With the second instrument synergy score (4.16), Shandong Province demonstrates the most detailed and scientifically designed policy texts. Its policy instruments are not only well-aligned with central government directives but also tailored to local conditions, ensuring feasibility and operational effectiveness. This reflects a high degree of sophistication in policy design and implementation.

Liaoning Province: Liaoning Province’s instrument synergy score of 4 places it third among the regions. Its policy instruments are generally aligned with central government frameworks, though there may be minor gaps in specificity or adaptability compared to Shandong and Tianjin.

Hebei Province: Hebei Province has the lowest instrument synergy score (3.73), suggesting a weaker alignment of its policy instruments with central government directives. This may reflect challenges in tailoring policy measures to local conditions or a lack of detailed and actionable policy design.

4.5. Comprehensive Evaluation of Vertical Policy Synergy

The overall vertical synergy indices for the three provinces and one municipality are as follows: Shandong Province (3.59), Liaoning Province (3.57), Hebei Province (3.07), and Tianjin Municipality (3.71). Ranking the regions from highest to lowest by vertical synergy yields the following order: Tianjin > Shandong Province > Liaoning Province > Hebei Province.

The results highlight significant regional variations in vertical policy synergy. Tianjin Municipality, with the highest vertical synergy index, demonstrates a strong alignment with central government priorities across all dimensions—subject, objective, and instrument synergy. Liaoning and Shandong provinces also exhibit relatively high levels of vertical synergy, though with minor differences in their respective scores. Hebei Province, however, lags significantly behind, with the lowest vertical synergy index, reflecting challenges in aligning its policies with central directives.

These findings underscore the importance of coherent and well-aligned policy frameworks in achieving effective environmental governance. Regions with lower vertical synergy scores, such as Hebei Province, could benefit from adopting more structured and detailed approaches to policy design, ensuring greater alignment with central government priorities. By doing so, they can enhance the effectiveness of their policies and contribute more effectively to the broader goals of Bohai Sea environmental governance.

5. Environmental Governance Effectiveness Analysis

In 2021, the Bohai Sea Comprehensive Environmental Governance Battle entered its final stage, and the governance work for the Bohai Rim Region was completed for acceptance; the Bohai Rim Region completed the remediation and restoration of 8891 hectares of coastal wetlands, exceeding the target requirement of 6900 hectares; 132 km of coastline was remediated and restored, exceeding the target requirement of 70 km; and 37.5% of the Bohai Sea’s nearshore waters were designated as the red line zone for the protection of marine ecology [37].

5.1. Outcomes of Three-Year Comprehensive Management Battle of Bohai Sea

According to the acceptance data for comprehensive management, 14 projects in Liaoning Province restored a total of 2,844.28 hectares of coastal wetland area and remediated and restored 47.33 km of shoreline, with completion rates of 149.7% and 157.8%, respectively [38].

In Hebei Province, by the end of 2020, restoration tasks had been completed for 800 hectares of coastal wetlands and 14km of shoreline, 1243.35 hectares of coastal wetlands had been repaired, 17.32km of shoreline had been restored, the width of the beach had been increased from 20 to 60 m, and the completion rates for the coastal wetland and shoreline remediation and coastal beach restoration tasks were 155.4% and 123.7%, respectively, with reference to the targets [39].

Tianjin city’s 12 rivers flowing into the sea improved from “all poor” in 2017 to “all eliminate poor” in 2020; the good water quality ratio of the city’s state-controlled section increased by 20 percentage points, and the proportion of poor V water quality decreased by 40 percentage points, reaching “zero”. The abatement ratio of “zero” ranks at the national forefront; the proportion of good water quality in nearshore waters reached 70.4%, an increase of 53.8 percentage points compared with 2017, the largest improvement in the Bohai Rim Region; furthermore, 4.78km of the shoreline remediation and restoration project and 531 hectares of the ecological wetland restoration project were completed, exceeding the national targets [40]. The targets had been to repair at least 400 hectares of coastal wetlands and to remediate and restore at least 4km of the shoreline by the end of 2020 [41]; the completion rates based on these targets were 119.5% and 132.8%, respectively. Shandong Province, during the implementation of the Bohai Sea comprehensive management battle, completed 3800 hectares of coastal wetland and 22 km of coastline shoreline restoration tasks. The Shandong Province Bohai Sea area completed the remediation and restoration of 4996 hectares of coastal wetlands and 62.82 km of shoreline, exceeding the targets [42], with completion rates of 131.5% and 285.5%, respectively. The data obtained for the Bohai Rim Region are summarized in

Table 6. Data for the results of the environmental management of the Bohai Rim Region (2018–2021).

	Shandong	Liaoning	Hebei	Tianjin
Existing wetland area (hectares)	245,500	294,000	135,900	33,000
Wetland restoration area (hectares)	4996	2844.28	1243.35	531
Achievement rate (%)	131.5	149.7	155.4	119.5
Restoration rate (%)	2.04	0.97	0.91	1.61
Coastline restoration length (km)	62.82	47.33	17.32	4.78
Coastline length (km)	3505	2290	487	153.7
Achievement rate (%)	285.5	157.8	123.7	132.8
Restoration rate (%)	1.79	2.07	3.56	3.11
Total achievement rate (%)	417	307.5	279.1	252.3
Total restoration rate (%)	3.83	3.04	4.47	4.72

:

It is worth noting that the absolute value of the area of wetland restoration in the Bohai Rim Region and the rate of achievement are not the only criteria for evaluating the comprehensive environmental management of this region, and that other elements such as improvements in water quality and the widening of the sandy beaches were not compared due to the inconsistency of the actual standards in different places.

5.2. Analysis of Policy Formulation and Implementation

On the basis of the data in

Table 7. The original data matrix.

	Tianjin	Liaoning	Shandong	Hebei
Policy number	16	34	32	15
Total restoration rate (%) rank	1	4	3	2
Total achievement rate (%) rank	4	2	1	3
Vertical synergy index rank	1	3	2	4

, this research utilized the entropy-weighted TOPSIS method for multi-index synthesis to evaluate the outcomes of policies in the Bohai Rim Region.

a.

Data Standardization

$$r_{ij}={\displaystyle \frac{\max \left(x_j\right)-x_{ij}}{\max \left(x_j\right)-\min \left(x_j\right)}}$$

(5)

After the data standardization, the final results are shown in

Table 8. The calculation results after data standardization.

	Tianjin	Liaoning	Shandong	Hebei	Max	Min
Policy number	0.947	0.000	0.105	1.000	34	15
Total restoration rate (%) rank	1.000	0.000	0.333	0.667	4	1
Total achievement rate (%) rank	0.000	0.667	1.000	0.333	4	1
Vertical synergy index rank	1.000	0.333	0.667	0.000	4	1

:

b.

Entropy weight method to determine weights

After calculations using Formulas (1)–(4), the comprehensive rankings were as shown in

Table 9. The calculation results for the final weight.

Index	ej	dj	wj
Policy number	0.621	0.379	0.271
Total restoration rate (%) rank	0.788	0.212	0.151
Total achievement rate (%) rank	0.788	0.212	0.151
Vertical synergy index rank	0.788	0.212	0.427

:

c.

Constructing a weighted normalization matrix

$$v_{ij}=w_j\times r_{ij}$$

(6)

The calculation results obtained with Formula (6) are shown in

Table 10. The calculation results for constructing a weighted normalization matrix.

Province	Policy Number	Total Restoration Rate (%) Rank	Total Achievement Rate (%) Rank	Vertical Synergy Index Rank
Tianjin	0.271 × 0.947 = 0.257	0.151 × 1=0.151	0.151 × 0 = 0	0.427 × 1 = 0.427
Liaoning	0.271 × 0 = 0	0.271 × 0 = 0	0.151 × 0.667 = 0.101	0.427 × 0.333 = 0.142
Sahndong	0.271 × 0.105 = 0.028	0.151 × 0.333 = 0.050	0.151 × 1 = 0.151	0.427 × 0.667 = 0.285
Hebei	0.271 × 1 = 0.271	0.151 × 0.667 = 0.101	0.151 × 0.333=0.050	0.427 × 0 = 0

.

d.

Calculating distance and proximity

$$S_i^{+}=\sqrt{\sum {(v_{ij}-V_j^{+})}^2},S_i^{-}=\sqrt{\sum {(v_{ij}-V_j^{-})}^2}$$

(7)

$$C_i={\displaystyle \frac{S_i^{-}}{{S_i^{+}+S}_i^{-}}}$$

(8)

After the final calculation, the final ranking was as shown in the table below:

As demonstrated in

Table 11. Ranking for policy formulation and implementation.

Province	S+	S−	Ci	Ranking
Tianjin	0.152	0.526	0.776	1
Liaoning	0.201	0.344	0.631	2
Sahndong	0.375	0.173	0.316	3
Hebei	0.468	0.271	0.367	4

, the analysis of policy formulation and implementation across the four regions revealed significant variations in their approaches to Bohai Sea environmental governance. Each region demonstrates distinct strengths and weaknesses, reflecting differences in policy alignment, implementation effectiveness, and outcomes.

Tianjin has the smallest geographic scope for Bohai Sea environmental governance among the four regions but has issued a relatively large number of local policy texts. Notably, Tianjin’s vertical policy synergy index is the highest, reflecting its strong alignment with the central government’s policy directives. This alignment demonstrates the scientific rigor and effectiveness of Tianjin’s policy formulation process. However, due to natural geographical constraints, such as its shorter coastline and smaller governance area, Tianjin’s absolute achievements in environmental governance are the lowest among the four regions. Its rate of achievement is comparable to that of Hebei Province, ranking in the bottom two. While Tianjin’s policy rationality is commendable, its actual environmental governance outcomes require further enhancement.

Liaoning Province stands out for its robust policymaking and practical actions in Bohai Sea environmental governance. It has issued the largest volume of policies among the four regions, and it ranks third in comprehensive policy formulation and implementation. Additionally, Liaoning ranks second in both the absolute value of wetland restoration areas and the rate of achievement. These results underscore Liaoning’s success in integrating central government priorities into its local policies and practices. Its achievements offer valuable insights and serve as a model for other regions seeking to improve their environmental governance frameworks.

The total achievement rate of Shandong Province is perfect, but the vertical coordination is not optimal. Shandong Province leads among the four regions in terms of absolute achievements and the rate of progress in Bohai Sea environmental management. It has the largest wetland restoration area and has issued the highest number of local policy texts. However, despite these accomplishments, Shandong ranks third among the four regions in terms of policy formulation and implementation, indicating a gap between its local policies and the central government’s strategic intent. While Shandong’s execution in the comprehensive remediation of the Bohai Sea environment is commendable, there is room for improvement in aligning its policy formulation and issuance with central government directives. Enhancing this alignment could further strengthen the effectiveness of its environmental governance efforts.

Hebei Province presents a unique case among the four regions. It scores the lowest across all indicators, including the vertical policy synergy index, rate of achievement, and volume of policy texts. However, Hebei ranks second in terms of restoration rate. While these results may not be generalizable, they highlight significant room for improvement in Hebei’s Bohai Sea environmental governance practices and policy formulation processes. Addressing these gaps will be critical for Hebei to align more effectively with central government priorities and achieve better environmental outcomes.

The analysis reveals a clear divergence in the performance of the four regions. Shandong excels in implementation but needs to improve policy alignment; Liaoning demonstrates strong policymaking and implementation; Tianjin shows high policy alignment but faces geographical limitations; and Hebei lags behind in both policy formulation and implementation. These findings underscore the importance of balancing policy alignment with practical implementation to achieve effective environmental governance. Regions with lower performance, such as Hebei, could benefit from adopting best practices from higher-performing regions like Liaoning and Tianjin.

6. Conclusions and Discussion

6.1. Comprehensive Consideration of Policy Subjects, Objectives, and Instruments in Bohai Sea Environmental Governance

The analysis of Bohai Sea environmental governance policies in three provinces and one municipality, using entropy weight and text analysis methods, reveals that the vertical synergy index is determined by three key indicators: policy subjects, objectives, and instruments. These indicators contribute evenly to the synergy index, suggesting that provinces should balance the roles of policy issuers, the selection of policy instruments, and the setting of objectives to enhance compatibility between local and central governance policies. The level of the issuing body reflects the importance provinces place on central policies, with provincial government documents playing a crucial role in policy dissemination. Despite similar weight coefficients (w1 = 0.334, w2 = 0.3327, and w3 = 0.33325), the policy subject’s weight is slightly higher, indicating that higher-level government documents tend to align more closely with central policies, enhancing vertical synergy.

Empirical evidence underscores the imperative to institutionalize vertical synergy metrics within provincial performance evaluation frameworks. Provinces demonstrating superior policy coordination efficacy and high attainment rates of Bohai Sea restoration targets—exemplified by Tianjin’s evidence-based policymaking paradigm—should pioneer targeted policy delivery mechanisms. This necessitates establishing interprovincial knowledge transfer platforms to codify and disseminate replicable governance innovations through case repositories and practitioner exchanges.

For jurisdictions achieving substantive environmental remediation outcomes yet constrained by suboptimal policy design rigor (e.g., Liaoning and Shandong), implementation of benchmark policy alignment initiatives is warranted. This involves the systematic adoption of Tianjin’s coordination protocols through institutionalized peer-learning mechanisms and cross-jurisdictional policy laboratories.

Conversely, provinces exhibiting acute synergy deficits (notably Hebei) require mandatory policy quality auditing systems, including pre-feasibility assessment protocols for legislative proposals and outcome-based ex-post evaluation matrices. Crucially, our analysis reveals that quantitative policy proliferation bears limited correlation with coordination effectiveness—the critical leverage point resides in vertical synergy infrastructure development, particularly intergovernmental decision-making synchronization and multi-level accountability circuits.

6.2. Incomplete Vertical Synergy Affects Governance Effectiveness

The vertical synergy of policies is closely related to the scientific nature of policy formulation. Scientific policy formulation requires full consideration of the rationality, clarity, synergy, stability, and fairness of the policy. However, in the process of formulating and implementing policies to comprehensively improve the Bohai Sea environment, some of the policy content lacks scientific assessment, resulting in poor policy implementation. For example, in terms of ecological restoration projects, some of the projects lacked systematicity and pertinence, and suffered from miniaturization and fragmentation, failing to fundamentally solve the problem of the Bohai Sea ecosystem’s degradation. In addition, the mechanism by which important ecosystems in the Bohai Sea degrade is not yet fully clear during the policy formulation process, affecting the precision and rationality of protection and restoration measures. Therefore, improving the scientific nature of policy formulation and strengthening the vertical synergy of policies is the key to enhancing the effectiveness of Bohai Sea environmental management.

The incomplete vertical synergy of policies significantly affects the effectiveness of governance during the implementation of comprehensive Bohai Sea environmental remediation policies. Although detailed policies and action plans have been formulated at both the national and local levels, such as the Action Plan for the Bohai Sea Comprehensive Remediation and Tianjin’s Three-Year Action Plan for the Comprehensive Remediation of the Bohai Sea, the shortcomings of policy synergies have gradually appeared in actual operation. For example, although the strict control of reclamation projects is clearly stipulated at the national level, there are still regulatory loopholes to a certain extent in local implementation, resulting in some projects being carried out without authorization and causing further damage to the ecological environment of the Bohai Sea. In addition, the provinces and municipalities along the Bohai Sea have ambiguous responsibilities and synergy difficulties in implementing the policy, which has led to inefficiency in the implementation of the policy and affected the overall effectiveness of governance. Therefore, the incomplete vertical synergy of policies is an important problem to be solved in the environmental governance of the Bohai Sea.

6.3. Limitations and Outlook

Looking ahead, the optimization of policies to comprehensively improve the Bohai Sea environment will show the following trends:

The first is deepening policy synergy, strengthening the vertical synergy between national and local policies, clarifying the division of responsibilities between all levels of government, and ensuring consistency and efficiency in policy implementation. By improving the policy synergy mechanism, the efficiency of policy implementation will be improved to ensure the realization of Bohai Sea environmental governance goals. The second is strengthening scientific governance. In the process of policy formulation, scientific assessment and research will be enhanced, a deeper understanding of the characteristics and degradation mechanisms of the Bohai Sea ecosystem will be attained, and more precise and reasonable protection and restoration measures will be formulated. At the same time, the systematic and targeted nature of ecological restoration projects will be promoted to improve the effectiveness of ecological restoration. Thirdly, regional linkage will be promoted, full play will be given to the advantages of Beijing–Tianjin–Hebei synergistic development, and the synergy among the provinces and cities along the Bohai Sea will be strengthened, so as to jointly promote the environmental management of the Bohai Sea. Through the establishment of a joint safeguarding mechanism, information sharing, resource complementation, and collaborative governance will be realized, and the challenges facing the Bohai Sea’s ecological environment will be jointly addressed. Fourthly, the scientific nature of the institutional system will be improved. The Bohai Sea environmental governance of the central policy promulgated in the policy subject, policy objectives, policy instruments, policy time, and other aspects of the policy generally have a strong scientific basis. The Bohai Sea provinces and cities, when formulating and introducing policies, should thoroughly grasp the policy objectives of the central policy documents, the policy instruments, and the introduction of time. The provinces and municipalities should respond to the national policy in time to respond to the call for important policies, policy objectives aligning with the central policy, the policy objectives of the central policy, and the introduction of time. The policy documents of each province and city should respond to the call for important national policies in time, and the policy objectives should be consistent with the central policy objectives; at the same time, it is necessary to combine the regional characteristics and development needs of each province and city, and formulate local policies according to the local conditions and innovativeness, in order to achieve the objectives of the governance of each province and city. In addition, the policy instruments of the Bohai Sea Environmental Governance Policy Documents issued by each province and city should encourage innovation and pragmatism, and the diversified and scientific use of policy instruments, in order to achieve high efficiency and convenience in the implementation of the policy.

6.4. Discussion

In conclusion, the effectiveness of Bohai Sea environmental governance is influenced by factors such as incomplete vertical synergy and the scientific rigor of policy formulation. By enhancing policy coordination, scientific governance, regional collaboration, and institutional frameworks, significant improvements in Bohai Sea environmental governance can be achieved, ensuring the long-term stability and health of the ecosystem. This study has certain limitations. Given that the Bohai Sea’s environmental governance has already achieved significant results and the action plan has concluded, the policy texts analyzed in this study were selected from the period between 2001 and 2021, with the end of the three-year action plan in 2021 serving as the cut-off point. Consequently, the findings of this study primarily reflect the state of Bohai Sea’s environmental governance up to 2022. Future research should continue to monitor the progress of Bohai Sea governance initiatives, incorporating the latest policy texts and regional documents from the Bohai Rim area to capture the most recent developments in governance efforts.