**1. Introduction**

Transboundary water is an important resource and a natural link that maintains relations between countries in the basin; this is also related to regional economic and social progress, world peace and stability, and the rapid development of human civilization. As of 2018, there are 310 international river basins in the world, shared by 150 countries, which cover 47.1% of the world's land surface and have 52% of the world's population residing within their boundaries [1]. However, shared water can indeed lead to regional tensions, threats, and even localized violence [2], and the unsustainable use of freshwater resources worldwide creates enormous challenges for human societies [3,4]. The excessive consumption of water resources in human production and life and the variation in water volume caused by climate change make international river basins face a great risk of conflict,

**Citation:** Yan, Z.; Qiu, X.; Du, D.; Grimes, S. Transboundary Water Cooperation in the Post-Cold War Era: Spatial Patterns and the Role of Proximity. *Int. J. Environ. Res. Public Health* **2022**, *19*, 1503. https:// doi.org/10.3390/ijerph19031503

Academic Editors: Alban Kuriqi, Luis Garrote and Jun Hou

Received: 15 November 2021 Accepted: 24 January 2022 Published: 28 January 2022

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and transboundary water resources are increasingly becoming the source of inter-country violent conflicts [5].

In 2014, the IPCC's (Intergovernmental Panel on Climate Change) Fifth Assessment Report made a serious estimate of the risks for global freshwater resources caused by climate change. It emphasizes that the risks for freshwater related to climate change and extreme events will increase significantly under the scenario of global warming of 1.5 ◦C [6]. As environmental changes will eventually lead to an increase in the economic and political value of water resources, this will increase the possibility of disputes between countries around transboundary water resources, and even the risk of military conflicts [7]. Furthermore, international river basins extend beyond national jurisdictions and their policy-making structures, making effective policy responses to them more difficult and prone to failure [4]. In the face of this dilemma, many basin countries facing water stress urgently call for international collective action to strengthen the rational control and effective governance of transboundary water resources. In the context of the in-depth development of world multi-polarization and economic globalization, and the unprecedented deepening of interdependence among countries, actively developing transboundary water cooperation (TWC) has become an inevitable choice for basin countries to enhance mutual trust. Therefore, we focus our research on the spatial pattern and generation mechanism of TWC between countries, which could substantially further our understanding of TWC issues.

This research may contribute to the literature in three ways. First, we applied the social network analysis method to TWC on the global scale, and quantitatively evaluated the status of the countries in the TWC networks and the connections between countries. Additionally, we visualized the networks geographically to better reveal the spatial pattern of TWC. Second, with the help of the multidimensional proximity framework, we studied whether the specific four relationships between countries (geographical, economic, organizational, and colonial proximities) have an impact on the intensity of TWC among countries. Third, we proposed a model that proximities further affect the willingness and ability of actors to cooperate, and ultimately leads to the emergence of the TWC intensity network pattern among countries. Which also extends the previous analysis of the TWC generation mechanism between countries. This also extends the previous analysis of the TWC generation mechanism between countries. Besides that, we have also expanded the current TWC events database to 2013. This is helpful for further research on the progress of TWC.

The research is structured as follows. Section 2 presents the literature review and the theoretical framework in this article. Section 3 introduces the research areas, the data, and research methods. Our main findings and discussion are reported in Section 4, and the final section offers conclusions and future research directions.
