Double-difference Method Research Articles

Relocation of the 8 September 2023 High Atlas, Morocco, Earthquake Aftershock Sequence

ABSTRACT The earthquake that occurred on 8 September 2023, with a magnitude of 6.8, was the most destructive earthquake event in Morocco in the past decade. This earthquake took place in the Al Haouz region, located in the western part of the High Atlas Mountain range. To better understand what caused and triggered this earthquake, the earthquake catalogs including P and S arrival times were collected from the Moroccan seismic network and combined with regional data from the International Seismological Centre. The mainshock and aftershocks were relocated by using iLoc, a state-of-the-art single-event location algorithm, and then by the multiple event location double-difference algorithm, hypoDD. The improved earthquake relocations using iLoc and the double-difference methods provide sharper lineation of seismicity and agree well with tomographic images of the earthquake zone. The seismicity distribution and the focal mechanism of the mainshock indicate that the earthquake sequence has occurred along the South Atlas fault system.

Quasi-real-time earthquake relocation and monitoring in the northeastern Noto Peninsula

The seismicity rate markedly increased in the northeastern Noto Peninsula of Ishikawa Prefecture around the end of 2020, with an Mw6.2 event on 5 May, 2023, followed by many aftershocks. Previous earthquake relocation studies have detected upward migration of microearthquakes via multiple faults and clusters, suggesting the involvement of crustal fluids in this sequence. Since some active faults exist near the source region, there was concern that this sequence could lead to a larger earthquake; it became a reality with the Mw7.5 earthquake on 1 January 2024. This study aims to develop an algorithm to precisely relocate microearthquake hypocenters in quasi-real time for better monitoring. A fine view of seismicity requires relative relocation methods such as the double-difference (DD) method with numerous arrival time difference data precisely measured by the waveform correlation analysis. However, the standard DD method has the disadvantage of huge computational costs when data increase, making it unsuitable for real-time monitoring in such situations. We developed a quasi-real-time algorithm that relocates only new earthquakes using the DD method each time a new time window of data is added. The major improvement is that our method incorporates a traditional simple relative relocation and preserves constraints between different time windows; the relative locations of new events are constrained from reference events that were already relocated in the previous time windows. We tested a daily relocation algorithm on 11,546 events from 19 June, 2022, to 31 May, 2023, in the Noto Peninsula earthquake sequence. We found that our modification substantially reduced artificial hypocenter offsets between different time windows and succeeded in resolving the fine fault structures from the cloud-like distribution of initial hypocenters. If we do not impose constraints between different windows, the relocated hypocenters are scattered and do not show fine planar structures. Our algorithm greatly reduces the computational cost, allowing for quasi-real-time earthquake relocation and monitoring. We hope this algorithm will help monitor the spatio-temporal distribution of future earthquake sequences.Graphical

The impact of socialisation services in the whole process of agricultural production on food security—quasi-natural experimental evidence from China

Food security (FS) is an important guarantee for world peace and development and the basis for building a community of human destiny, which has a bearing on the sustainable development and future destiny of humankind. This study empirically analysis the relationship between socialisation services in the whole process of agricultural production (ASS) and guaranteeing FS, as well as the path of their role, using provincial panel data from 2010 to 2022 in China as an example, using the double-difference method. The regression results show that ASS can have the ability to contribute to the level of FS, and the conclusion still holds after a series of robustness tests. The results of the heterogeneity analysis show that the role of ASS in guaranteeing FS receives the influence of the level of agricultural development in each region, while it plays a greater role in the main food-producing areas. The mechanism analysis analyses the mechanism of the role of ASS in the whole process of agricultural production in guaranteeing FS from the three links of pre-production, mid-production and post-production respectively, and finds that ASS in the whole process of agricultural production is able to guarantee FS by reducing the cost of purchasing means of production in the pre-production stage, fostering a new type of agricultural management main body in the mid-production stage, and increasing the income of farmers’ household management in the post-production stage. Based on the above findings, this study proposes corresponding policy recommendations. This study can provide insights for ensuring world FS and contribute to maintaining social stability and development. The conclusions of the study are universally applicable, and all countries in the world can benefit from and draw lessons from it.

The Impact of the National Civilized City Program on the Environmental, Social and Governance Performance of Enterprises: Evidence from China

The National Civilized City Program is an important governance championship for cities in China. Taking the National Civilized City Program as a quasi-natural experiment, based on the data of A-share listed companies in Shanghai and Shenzhen from 2009 to 2021, the multi-period double-difference method is used to investigate the impact, mechanism of action and heterogeneity of the National Civilized City Program on corporate ESG performance. It is found that the National Civilized City Program can significantly enhance corporate ESG performance, and this conclusion still holds after a series of robustness tests. The National Civilized City Program improves corporate ESG performance through two channels: strengthening environmental regulation and promoting the fulfillment of corporate responsibility towards employees. There is significant heterogeneity in terms of geography, firm ownership and pollution attributes in the impact of the National Civilized City Program on firms’ ESG performance.

Can E-Commerce Policies Drive Common Wealth Levels —— A Study Based on County-Level Data in China, 2012-2020

Based on national county panel data from 2012 to 2020, this study systematically examines the impact of the comprehensive e-commerce into rural areas demonstration project implemented in rural China on promoting the level of common wealth by applying the multi-period double-difference method (DID). It is found that the e-commerce policy significantly enhances the level of common wealth. Further analysis of the impact mechanism shows that the policy effectively promotes the goal of common prosperity by enhancing the level of rural employment. In addition, the positive effect of the e-commerce policy is strengthened by the increase in the level of local government fiscal expenditure, however, the driving effect of the policy is weakened by the higher level of social consumption. Heterogeneity analyses indicate that the policy's promotional effect is particularly significant in the demonstration counties of the Yangtze River Economic Belt. This paper fills the research gap on the relationship between rural e-commerce policy and the level of common wealth, and provides empirical evidence and policy recommendations for related policy formulation.

Impact Study of Environment Public Interests Litigation on Carbon Emissions: Taking Pilot Policy of Procuratorial Public Interest Litigation as a Quasi-Natural Experiment

The environmental problems caused by carbon emission have become the focus of worldwide attention. Effective control of carbon emissions cannot be achieved without the protection of the rule of law. Environment public interests litigation is a prominent innovation in the judicial system, and its role in supervising the government to perform its regulatory duties on carbon reduction and regulating the carbon emission behaviors of enterprises and the public deserves discussion. The paper selected the panel data from 274 prefecture-level cities from 2013 to 2021 and analyzed the impact of a procuratorial public interest litigation pilot policy on carbon emission control by using the double difference method. The research found that the procuratorial public interest litigation pilot policy can effectively curb carbon emissions. Heterogeneity analysis showed that in cities with relatively low level of green innovation, the negative correlation between procuratorial public interest litigation pilot policies and carbon emissions is more significant. Compared with the eastern region, in the central and western regions, especially in the central region, where the concept, policy, and funding of carbon emission governance are relatively weak, the implementation of the pilot policy of procuratorial public interest litigation had a more obvious effect on carbon emission governance. Mechanism tests showed that procuratorial public interest litigation policies reduce carbon emissions by reducing energy consumption and increasing public participation in environmental protection. The study will provide an empirical basis for the carbon emission reduction effect on pilot policy of procuratorial public interest litigation and will offer certain theoretical recommendations for improving the procuratorial public interest litigation system in the ecological environment field.

3-D P-wave velocity structure of the upper mantle beneath eastern Indonesia from body wave tomography

Eastern Indonesia's tectonic setting is well known for its complexity and intense seismic activity. Controlled by several major and minor plates, including the Eurasian, Australian, and Pacific plates, this region is famous for its U-shaped subduction system beneath the Banda Arc. To better understand the architecture of the underlying structure in this region, we performed body-wave travel time tomography using ten years of catalog data provided by the Indonesian Agency for Meteorology, Climatology, and Geophysics. We utilize 9729 events in total, from which 46,446 P-wave arrival times were extracted. We used a double difference method to relocate the initial event catalog, which produced a pattern of seismicity consistent with a curved subduction system. Our tomographic model reveals a high velocity band between 90 and 240 km depth in the upper mantle, which is interpreted to be a concave dipping lithospheric slab that is parallel to the present-day Banda arc. Our results also show that lithosphere subducting from the north and south starts to collide at a depth of 300–350 km and becomes shallower further east. Apparent discontinuities in the high velocity band and a corresponding lack of seismicity supports the presence of a slab tear to the west of Seram. A dipping high velocity structure that is present from south to north beneath the island of Timor represents a subducting slab that dips more steeply beyond a depth of 150–200 km, which appears consistent with slab roll-back. Our tomographic model also shows evidence of back arc thrusting to the north of Sumbawa and Flores Islands in the form of a south-dipping higher velocity band at shallow depth. Furthermore, our tomographic models also reveal the possible presence of underthrust continental forearc in the form of a thin higher velocity anomaly that connects the backarc thrust and northward dipping lithosphere slab in the Timor area. Finally, a zone of low velocity above the higher velocity slab is clearly seen beneath Seram Island at a depth of ∼100 km and may represent a partial melting zone.

Does the Innovative City Pilot Policy Promote Urban Energy Use Efficiency? Evidence from China

The innovative city pilot policy (ICPP) is a key policy practice in China’s innovation-driven economic strategy, yet its influence on urban energy use efficiency (UEUE) has yet to be assessed. This study used balanced panel data from Chinese cities from the period of 2006 to 2022 to investigate the impact of innovative cities on urban energy consumption efficiency. The double-difference method, which treats creative cities as quasi-natural experiments, was applied to identify the impact mechanism of these cities. Additionally, this study looked at heterogeneity from several angles and assessed the effects of the policy on the environment. Following thorough testing to guarantee the reliability of the findings of this study—such as changing variables, ruling out further policy interferences, and running placebo tests—it can be concluded that the pilot program significantly improves urban energy consumption. The mechanism analysis performed in this study shows that, via talent concentration, utilizing technology, and optimizing the industrial structure, the creative city pilot policies increase energy consumption efficiency. Additionally, a heterogeneity analysis shows that eastern cities and cities with a high degree of digital finance benefit most from the legislation in terms of energy consumption efficiency. The application of creative city pilot programs has a more noticeable effect on increasing the energy consumption efficiency in eastern cities, as well as in cities with a high degree of digital infrastructure and digital finance, according to the heterogeneity analysis. Furthermore, an environmental consequence test shows that, by encouraging the growth of UEUE, the development of innovative cities can successfully help to reduce carbon emissions.

Assessing the impact of free trade agreement (FTA) signing on China’s outbound labor services

This study utilizes panel data encompassing 164 countries to analyze China’s foreign labor export from 2008 to 2017. Employing the multi-period double-difference method, the research investigates the impact of Free Trade Agreement (FTA) signings on China’s labor export. Empirical findings reveal the following insights:The signing of FTAs significantly enhances China’s foreign labor export, demonstrating a temporal effect. Importantly, this conclusion withstands rigorous testing through various robustness checks. FTAs have a positive impact on China’s labor export to developing countries but do not exhibit a similar effect on developed countries. The impact of FTAs on labor export is pronounced in contractual engineering scenarios, while no discernible effect is observed in China’s labor cooperation. Through a meticulous examination of specific WTO+ and WTO-X provisions, the study underscores that it is primarily the WTO+ provisions that drive China’s foreign labor export. Consequently, strategic recommendations are proposed. These include fostering additional FTAs between China and developing nations, prioritizing labor export within contracted projects, encouraging expansion of Chinese labor export enterprises into new markets, promoting multi-party cooperation to facilitate overseas labor export, diligent consideration of existing FTA provisions, and exploration of transitioning from WTO+ to WTO-X provisions.

Do Green Finance Policies Inhibit the Financialization of Manufacturing Enterprises? Empirical Evidence Based on a Quasi-Natural Experiment with the “Green Credit Guidelines”

Against the background of the increasing financialization of manufacturing enterprises, whether green financial policies can inhibit the financialization of manufacturing enterprises is a major practical issue worth exploring. It can help government departments to guide the sustainable development of the real economy of enterprises, effectively curbing the trend of over-financialization of enterprises, thus preventing potential systemic risks and safeguarding the sustainable development of the economy. Because the green credit guidelines function as a more mature development of green financial policies, this paper takes Chinese A-share listed companies from 2005 to 2022 as the research sample, adopts the propensity score matching and double difference method, and constructs a quasi-natural experiment with the “Green Credit Guidelines” as the policy shock to analyze the multiple impact effects of green financial policies on the financialization of manufacturing enterprises. The results of the study show that (1) green finance policy has a significant inhibiting effect on the financialization of manufacturing enterprises; (2) due to the different motives of manufacturing enterprises in holding financial assets, green finance policy has a more significant inhibiting effect on the long-term financialization of “substitution”; (3) state-owned enterprises (SOEs) bear more social responsibilities and have credit advantages. Green finance policy has a more obvious inhibiting effect on the financialization of non-state-owned manufacturing enterprises; (4) major shareholders can play a better supervisory role in enterprises with high equity concentrations, so green finance policy has a more significant inhibiting effect on the financialization of manufacturing enterprises with low equity concentrations; (5) financing constraints have a masking effect in green finance policy and enterprise financialization. Based on this, this paper puts forward the following targeted recommendations. For the governmental level: first, to establish a sound manufacturing credit system; second, to focus on enterprise-financing constraints. For the enterprise level: first, to optimize the asset structure to promote transformation; second, to deepen the mixed ownership reform of state-owned enterprises.

Relocation of the 2018–2022 seismic sequences at the Central Gulf of Corinth: New evidence for north-dipping, low angle faulting

The Gulf of Corinth, Central Greece, is a highly active half-graben, characterized by seismicity which is more intense in its western part, while destructive earthquakes have also occurred towards its eastern end. We herein present an analysis of the seismicity in the Central Gulf of Corinth, for the period from June 2018 to December 2022. We applied the EQTransformer machine-learning model to enhance the initially available data, adding missing P- and S-wave arrival-times or improving existing ones. The events were initially located using a new local velocity model and then relocated using the double-difference method, including waveform cross-correlation data from local stations. The hypocenters, generally distributed at depths between 5 and 15 km, along with the focal mechanisms of significant earthquakes (1965 through 2022) and the geometry of mapped faults on the surface were co-examined to better understand their possible connection. It is shown that major outcropping north-dipping structures, such as the East Helike fault and its eastward offshore extension, match only with the southern bounds of seismicity. The Mw = 5.9, 1970 Antikira and Mw = 5.7, 1992 Galaxidi earthquakes cannot be associated with known mapped faults on the surface and likely occurred on low-angle, north-dipping planes. The variability in slip behavior of the low-angle detachment in the Gulf of Corinth, ranging from seismic slip to aseismic creep, probably accounts for the most part of the N-S extensional deformation. The spatial pattern of the 2018–2022 microseismicity delineates the edges of the rupture planes of major events that occurred during the instrumental era, including the Mw = 6.3, 1995 Aigion earthquake. The lack of aftershocks for significant earthquakes, including the Mw = 5.0, 8 October 2022 event, south of Desfina, is interpreted in terms of different pore pressure conditions, variations in fault-rock strength, and the preferred accumulation of high stress inside the upper crust.

Trade Creation or Diversion?—Evidence from China’s Forest Wood Product Trade

In recent years, trade protectionism and unilateralism have prevailed, and countries around the world have imposed restrictions on log exports. It has also become more difficult for China to import wood resources and export deep-processed wood forest products. Based on panel data from 2000 to 2019, this study uses social network analysis to measure the level of the Chinese wood forest product trade network, takes the Chinese free trade agreements (FTAs) as the natural experiment, and uses the multi-stage double-difference method to investigate the impact of the signed FTAs on China’s wood forest product trade. The study finds that the trade network of Chinese wood forest products is becoming increasingly complex, and the central position of China and the Association of Southeast Asian Nations (ASEAN) in the network is increasing year by year. The signing of FTAs has had a significant positive impact on the trade of wood forest products in China and a significant trade creation effect. This finding remains true after conducting the placebo test and propensity score-matched regression control. At the same time, the import of wood forest products in China will have a significant trade transfer effect due to the signing of FTAs, and this will not affect exports. Although FTAs show significant trade creation and trade transfer effects in China’s wood forest product trade, they also increase, to a certain extent, the mismatch of forest resources worldwide.

The Policy of Cross Border E-Commerce Comprehensive Pilot Zone and the Growth of Urban Total Factor Productivity — Empirical Testing Based on Double Difference Method

Since the establishment of the first pilot zone in 2015, China’s cross border e-commerce has rapidly developed, becoming a new engine driving international trade. This paper delves into the impact of China’s cross border e-commerce comprehensive pilot zones on urban total factor productivity. The paper first provides an overview of the development trajectory and current status of cross border e-commerce comprehensive pilot zones and analyzes the potential mechanisms through which these pilot zones might affect urban TFP. Utilizing data from 70 major cities between 2011 and 2019, the study employs a Difference-in-Differences approach to evaluate the impact of the pilot zone policies on urban TFP growth. The results indicate that the establishment of pilot zones significantly enhances urban TFP growth rates, with more pronounced effects in the eastern regions. The regional heterogeneity test reveals that the pilot zones positively influence TFP growth in the eastern and central regions, while the impact on the western and northeastern regions is not significant. Robustness checks further confirm the significance of the policy effects. Based on the findings, the paper proposes policy recommendations, including strengthening policy support, enhancing infrastructure development, reinforcing technological innovation capabilities, and promoting regional coordinated development to fully leverage the role of cross border e-commerce comprehensive pilot zones in boosting urban TFP and driving high-quality economic development. Overall, this paper provides empirical evidence for understanding how cross border e-commerce comprehensive pilot zones enhance urban TFP through technological innovation and policy support, offering important insights for optimizing relevant policies and promoting regional economic development.

From poverty to prosperity: assessing of sustainable poverty reduction effect of “welfare-to-work” in Chinese counties

The “welfare-to-work” program is a comprehensive supportive policy in the 14th five-year plan period in China. In this paper, a systematical assessment of the long-run effectiveness of the welfare-to-work policy on poverty reduction is of great significance to stimulate the internal impetus of people who are lifted out of poverty to achieve income growth and prosperity and promote regional economic development. Based on the data at the county (city) level in China from 2000 to 2019 and the sustainable development theory, in this paper, a county-relative poverty evaluation system was constructed. Besides, the double difference method was employed to evaluate the effect of the welfare-to-work policy on poverty reduction and test its action mechanism. The findings are as follows: (1) the welfare-to-work policy has a significant poverty reduction effect and presents an inverted “U” shape. In addition, significant achievements have been made in “maintaining employment stability, ensuring income, strengthening skills, and supporting the economy” ; (2) the welfare-to-work policy boosts poverty reduction in counties through infrastructure construction, fiscal intervention, and financial tools; however, the financial tools play a positive role in poverty reduction in the northwest region and suppressed role in the southwest region, and has an insignificant effect in the central region; and (3) there are differences in the effect of poverty alleviation policies of the counties with different sustainable development levels, and the regions with higher development level have a stronger driving effect.

Seismic source analysis of the destructive earthquake November 21, 2022, Mw 5.6 Cianjur (Indonesia) from relocated aftershock

A destructive shallow earthquake with a magnitude of 5.6 struck Cianjur, West Java, Indonesia on November 21, 2022. This earthquake resulted in 602 casualties and the collapse of over 67,504 residences. The day after the mainshock, we deployed 19 temporary seismic stations to monitor aftershocks for a period of 30 days. We manually picked arrival times for 4499 P-waves and 3419 S-waves and determined locations for 514 events. Following the velocity model update, phase refinement through waveform cross correlation, and relocation using double-difference methods, we were able to determine 442 well-defined hypocenters of the aftershocks. We identified two clusters of aftershocks: one in the NNW-SSE direction, with a length of about 8 km, and another in the WSW-ENE direction, with a length of around 6 km. The seismogenic zone of these clusters ranges from a depth of 3 to 13 km. Our interpretation suggests that these clusters may indicate a conjugate fault. It is possible that the mainshock (Mw5.6) Cianjur earthquake on November 21, 2022 occurred on the WSW-ENE direction with sinistral movement.

The impact of internet use on entrepreneurial behavior and income: Evidence from Chinese rural households

China's low-income population is primarily mad up of farmers. Elevating their earnings is the key to realizing common prosperity. Based on the quasi-natural experiment of the "Broadband China" strategy, we applied the staggered double difference method to explore the impact of Internet use on the income of Chinese rural households. The findings indicate that Internet use can enhance the business income of rural households, whereas it does not have such significantly positive effects on other income. After mitigating endogeneity issues, the basic pattern of the effects remains. The heterogeneity analysis reveals that females and individuals with higher levels of education benefit more from the "Broadband China" policy. The mechanism results show that Income boosting effect may arise from improving rural entrepreneurship behavior.

Does Urban Innovation Promote Rural Entrepreneurship? Quasi-Natural Experimental Evidence from Microdata on New Agricultural Subjects

Rural entrepreneurship has injected new vitality into the comprehensive realization of rural revitalization, and exploring the impact of urban innovation and development on rural entrepreneurship is of great significance in promoting the comprehensive revitalization of the countryside and achieving the coordinated development of urban and rural areas. This paper utilizes the panel data of 284 cities in China from 2005 to 2020 and adopts the multi-period double-difference method to test the effect of innovative city pilots on the entrepreneurial level of new agricultural management subjects, so as to reflect the impact of innovation policy on rural entrepreneurship. The study finds that innovative city construction significantly improves the entrepreneurship level of new agricultural business subjects and that the policy effect continues to increase over time, which is still robust after considering endogeneity issues. The above effects are mainly achieved through improving scientific and technological inputs, enhancing credit support effects, and promoting scientific and technological progress. In the heterogeneity test, innovative city construction significantly promotes the entrepreneurship level of new agricultural business subjects in both small and medium-sized cities and cities with a high level of science and education, but significantly inhibits the entrepreneurship level of new agricultural management subjects in large cities and cities with a high level of science and education. At the same time, innovative city development promotes higher levels of entrepreneurship only in agricultural cooperatives and agribusinesses, with no significant effect on family farms. This study has important policy references for accelerating innovative city construction and rural revitalization development in China in the new era.

Digital economy and urban innovation level: A quasi-natural experiment from the strategy of “Digital China”

The digital economy is an essential engine of the innovation-driven development strategy and plays a valuable role in promoting the high-quality development of the regional economy. Based on the panel data of 286 cities in mainland China with the help of the digital economy strategic plans issued by local governments as a quasi-natural experiment, we use the multi-temporal double-difference (DID) method to examine the impact of the digital economy on the urban innovation level. Findings show that the digital economy can significantly improve the urban innovation level. After a series of robustness tests, such as parallel trend test, updating sample and period, and repeated placebo test, the innovation-driving effect generated by the development of the digital economy remains significant. Results of the mechanism analysis indicate that the digital economy enhances the level of innovation through upgrading industrial structures. In addition, we find through the heterogeneity test that the digital economy has a stronger effect on improving the quality of innovation. Meanwhile, the innovation output in the Middle Eastern region is more significantly affected by the “Digital China” strategy than the Western region. Therefore, we should accelerate the implementation of the local digital economy development strategy to realize the high-quality development of the regional economy.

Does Green Finance Affect Economic Performance? Growth and Crowding-Out Consequences

ABSTRACT Green finance is crucial to the achievement of China’s dual-carbon goals and its sustainable economic development. Based on the data from 2011 to 2020, This paper employs a double-difference method to examine two effects of green finance on economic growth, namely, its growth and crowding-out effect. The empirical results show that, in general, green finance improves the level of economic growth and doesn’t impede the entry of new enterprises, while crowding out the contribution of heavy polluting industries to the economy. Green financial policies effect economic performance mainly through resource allocation and technological innovation. Specially, in comparison to the central and western regions, green finance exerts a more pronounced influence in the eastern region, potentially attributable to disparities in regional development levels, financial system efficiency, and degrees of marketization. In addition, both growth and crowding-out effect are more significant in resource-dependent cities.

Carbon emission allowances and green development efficiency

This study delves into the nexus between the efficiency of carbon emission allocation and the efficiency of green development within the context of innovative city construction. Leveraging data from 283 prefecture-level cities and corresponding provincial-level panel data spanning the period from 2005 to 2019 in mainland China, the research employs the zero-sum gain DEA model to compute provincial carbon emission allocation efficiency and allocate allowances. Furthermore, it utilizes the all-factor non-radial directional distance function and the SBM-DEA model to gauge the green development efficiency of prefecture-level cities. The double-difference method is applied to evaluate the impact of innovative city construction on regional green development efficiency. The results indicate that an imbalance between carbon emission allocation efficiency and emission quotas detrimentally affects urban green development. However, technological progress, factor accumulation, and the institutional environment associated with innovative city building mitigate this negative impact. Heterogeneity analysis reveals a differentiated effect of innovative city building on regional green development efficiency. This paper not only explores the concept of achieving an equitable distribution of carbon emission allowances but also examines how innovative city building influences regional green development. By establishing connections between urban policies, the equitable distribution of carbon emission allowances, and regional green development, it introduces a new perspective for promoting high-quality development at the regional level.