TRANSBOUNDARY REGIONS OF EAST ASIA: GEOGRAPHICAL AND POLITICAL PRECONDITIONS AND LIMITATIONS TO LONG-TERM DEVELOPMENT

. The contradictory integrity of globalization and regionalization processes in the modern world has been embodied in the formation of specific spatial areas – multiscale cross-border regions, whose functioning and development are determined both by the interactions between neighboring countries and by the totality of external geopolitical and geo-economic circumstances. The article is devoted to the factors and features of cross-border processes and socio-economic development within one of the largest and most dynamic structures of modern Eurasia – the Greater Macro-Region of East Asia, embracing the northeastern and eastern territories of Russia, eastern China, Japan, and both Korean republics, Vietnam, and a number of other countries facing the seas of the northwestern Pacific. The integrity of this vast and very heterogeneous macro-region ranging from Chukotka to the Philippine Sea is based on relatively stable cross-border relations, which, in turn, are one of the determinants of these territories’ development. The role of geographical prerequisites (geographical location, climatic conditions, natural resources of land and sea) and geopolitical factors (geopolitical location and cross-border features) in the long-term development of this macro-region is assessed. It is shown that both favorable and negative prerequisites are associated with the cross-border nature of the integrated geosystems, including the marine ecosystems. Various types of cross-border regions with two-, three-, and four-link territorial segments belonging to different countries have been identified. The geopolitical potential of countries and regions is assessed, and the zones of geopolitical tension are revealed.


INTRODUCTION
East Asia is a large, meridionally extended macro-region situated at the junction of the largest continent (Eurasia) and two oceans (the Arctic and the Pacific). In literature, there is no strict definition of the East Asia composition. The macroregion is defined differently among the countries of China, Japan, Republic of Korea and DPRK (Pacific Russia 2017; Terada 2006). As such, the Russian Far East and Southeast Asian nations are not always included in this region. More often, Northeast Asia is identified as a composition of Northeast China, the Russian Far East, DPRK, Republic of Korea and Japan (Pacific Russia 2017;Tulokhonov 2014;Womarck Brantly 2014). A.G. Druzhinin proposes a new approach to structuring of Eurasia based on a geo-ethnocultural systems conception (Druzhinin 2016). The Asiatic group of such systems is identified without concretization of their composition.
At present, the largest region -the North Pacific, including the USA, is identified but its full configuration is not always consistent (Geopolitical potential 2010; Pacific Russia 2017). In our opinion, East Asia is a more integral region. Taking into account similarity of geographical positions, we included the territorial subjects of the Russian Federation (RF) adjacent to the Pacific Ocean, the eastern portions of China, and all countries entering the seas and the North Pacific in East Asia. This macro-region extends over nearly eight thousand kilometers from north to south (Fig. 1).
The specific features of East Asia include great differences and the contrasts of its particular territories and regions if considered from different perspectives. So, from the environmental standpoint, the macro-region houses virtually all natural zones of the Earth: from the ice Arctic deserts of North Siberia and Chukotka to the tropical forests of Indonesia. The macro-region is characterized by the most diverse combinations of the natural resources of the land and adjoining seas and oceans. In East Asia, the unique diversity of civilizations and cultures was formed including the unique Chinese, Korean, Japanese, and paleo-Asiatic ones, as well as the Russian northern indigenous nations represented by the Yakuts, Chukchi, Koryaks. Finally, in the countries of East Asia, the strong diverse political systems have emerged: presidential republics (Russia, Republic of Korea etc.), constitutional monarchies (Japan, Thailand), the countries of socialist orientation (China, Vietnam), and DPRK, a country with the communist political regime).
The differences in the levels of the social and economic development in East Asian countries are also considerable. Highly-developed countries (i.e. Japan, Singapore and Republic of Korea), dynamically developing ones (i.e. China, Malaysia, Vietnam and Russia) and less-developed states (i.e. Thailand, Laos, Myanmar, Indonesia and Philippines) are found side by side.
The critical characteristic unifying the countries and the regions of East Asia derives from their transboundary nature. Thus, a great part of the Russian Far East and Northeast China are included into the transboundary basins of the Chukchi, Bering, Okhotsk, Japan, and Yellow seas. In addition, there are several transboundary river basins in the East-Asia region including the Amur, the Ussuri, and the Tumen. The basins of the East China, South China, as well as the Philippine seas are also transboundary. According to our estimates, the transboundary regions of East Asia include practically 100% of its territory. Therefore, the transboundary phenomenon is the most important factor for East Asia combining its regions and countries into one integrated transboundary space.
The environmental, social-economic, cultural, and political characteristics of the macro-region combine to form a pattern that is diverse and unique. The dynamics of the separate parts and structures of this space are determined in many respects by the effect of the geographical and geopolitical factors. These factors also have different impacts on the long-term development of the countries and regions of East Asia. Such separate factors create the favorable prerequisites for the regional development, while the others restrict them. As a whole, the combined impact of the geographical and geopolitical factors and their spatial differentiation on the long-term development of the East Asia macro-region has not been practically investigated. Some works were devoted to Northeast Asia (Baklanov 2000;Geopolitical potential 2010;Larin 2016;Nature management 2005;Tkachenko 2009;Womarck Brantly 2014), the Far-Eastern region of Russia (Baklanov et al. 2016;Baklanov et al. 2015;Larin 2016), Northeast China, Vietnam (Baklanov et al. 2017;Larin 2014;Nature management 2005), the countries of Southeast Asia (Asia-Pacific 2010; Baklanov et al. 2017;Pacific Russia 2017). However, the transboundary nature of the macro-region presents additional complexity to understanding its long-term development. Therefore, the task of this paper is to make an aggregated assessment of the geographical and geopolitical factors and their role in the long-term development of the macro-region.

The main geographical and geopolitical factors
The geographical factors exerting a significant influence on the long-term development of the macro-region include their geographical and economic-geographical positions, the effect of the natural-climatic conditions due to their spatial differentiation, as well as a natural-resource potential in the form of the territorial and aqua-territorial combinations of natural resources.
The most important characteristic of the geographical position of East Asia resides in the fact that its greater part is a zone of the global contact among geographical structures (Baklanov 2000). Firstly, this is a junction between Northeast of Eurasia and the Pacific and Arctic Oceans resulting in different interrelations between land and the sea in the natural-ecological, natural-resource and economical spheres. Secondly, this is the place where Russia borders the world's largest economies (the USA, China and Japan). The contact structures serve as the basis for performing various functions, including utilization of different natural marine resources supported by inshore infrastructure in combination with terrestrial resources. The proximity and dynamic development of the countries of the macro-region generate the external-economic interactions through the joint partnership of land-based and marine transport systems, which in turn contribute to the extension of the market spaces.
The southern portions of the Russian Far East, the southeast portions of China as well as the areas of Vietnam, Singapore and Malaysia have the most favorable economic-geographical position from the viewpoint of interfacing with the external transportation routes and proximity to the developing markets.
Due to a variety of natural conditions, the most favorable opportunities for sustainable development are found in the southern areas of the Russian Far East and East China. Low temperatures, permafrost and other extreme conditions become the limiting factors in the central and northern portions of the Russian Far East. In the areas of East Indo-China, the tropical extreme natural processes, such as typhoons, floods and tsunami are frequent, although many of these regions are most favorable for cultivation of rice. Local populations have generally adapted to these naturalclimatic disturbances (Baklanov et al. 2017).
For some areas of East Asia and adjacent seas, one can identify both land-based and aqua-terrestrial resources. Their similarity and differences for different areas, as well as their generalized natural-resource potential were estimated. The regions of the Russian Far East, Northeast China, Malaysia, Indonesia and Myanmar hold the highest potential. As a whole, one can note the great complementarity of landbased natural resources with marine natural resources, as well as some complementarity of natural resources in certain neighboring areas, like between the Russian Far East, Northeast China, Japan, Republic of Korea and DPRK (Nature management 2005; Tkachenko 2009). Such complementarity of land-based natural resources with those of the marine origin, as well as natural resources between neighboring countries, which is typical in the regions and countries of East Asia, create favorable conditions for the long-term sustainable development.
It should be noted that the regional contrasts within the transboundary space are generally large. Here, one finds neighboring countries vastly differing both by their size and development level (Table 1). The world's largest countries are China (18.7% of global GDP in 2018), Japan (4.1%) and Russia (3.1%). Smaller countries include Indonesia (2.6%), Republic of Korea (1.6%), Malaysia (0.74%), while Singapore is a small but highly-developed country.
As the Table shows, from 1990 to 2018, many countries of East Eurasia have demonstrated extremely high rates of development: China has increased its GDP by 2,162%, Myanmar by 1,727%, Laos by 1,013%, Vietnam by 1,005%, Malaysia by 709%, Indonesia by 542% and Philippines by 491%. This is in contrast to many other regions of the world, where increases in the GDP have been lower. For example, the GDP during this same period has increased in the EU by 227%, the USA by 244%, Russia by 236%, and for the world taken together -by 370% (gtmarket.ru 2019; fincan.ru 2019). Among the geopolitical factors essential in the longterm development of the macro-region, we consider the geopolitical position of East Asia as a whole and its separate regions, as well as its transboundary phenomenon to be an important specific characteristic of the geopolitical position of the macro-region.
The essential features of the geopolitical position of this macro-region are determined by Russia and China, the eastern areas of which belong directly to East Asia. Russia and China have different "weights" and political systems but, in recent years, the strategic partnership was established between them.
The crucial component of the geopolitical position of the macro-region is the proximate neighborhood with the USA and strategic partnership between the USA, Japan and Republic of Korea that enhances geopolitical contrasts. The USA is one of the three largest countries by its geopolitical potential in the world (15.2% of the global GDP). It neighbors Russia and East Asia across the Bering Strait. The essential specific geopolitical role is performed by Japan. Being territorially a part of East Asia, this country has the closest and large economic and military-political ties with the USA. In this "team", Japan can be simultaneously considered an external geopolitical factor in East Asia. Its vicinity to the countries of Oceania and Australia, varying by political systems, is also of great geopolitical importance for East Asia.
In Eastern Asia, significant differences between countries and regions are reflected in their geopolitical potential (Table  2). On the one hand, China, Russia, and the USA are the largest countries of the world in terms of their geopolitical potential; and to perhaps a similar extent so is Japan and the Republic of Korea. However, there are a number of countries that have medium and small potential values.
Even greater contrast is reflected by the relative characteristics of the development of the territories including those which belong to the transboundary regions (Table  3). On the one hand, these estimates reflect a cumulative effect of the geographical factors on the development of the territories and, on the other hand, they reflect, perhaps to a larger extent, their geopolitical stability.
Generally, taking into consideration a transboundary phenomenon, the sea water area crossed by national frontiers, and the portions mainland of the territories adjacent to it to some extent become the influence zones of neighboring countries and the zones of intersection of their mutual geopolitical interests. The estimates of the natural-resource potential owned by one country (in the coastal areas and marine exclusive economic zone) and, especially, stability and efficiency of the national types of resource management in the neighboring countries become interrelated and interdependent. This refers to all transboundary regions. According to our research (Baklanov et al. 2008;Baklanov et al. 2015; Geopolitical potential 2010), a transboundary phenomenon creates both favorable and negative conditions for the long-term development. So, when reaching the high standards of natural resource management in a neighboring country, the space and efficiency of the renewable resources regeneration (fish, forest, land etc.) are extended.
Under otherwise equal conditions, the integrity of the transboundary geosystems (including the marine ecosystem) creates objective opportunities for the longterm international cooperation of the countries within the transboundary region. This contributes to the rise of a sustainable natural resources management system, extension of the market space, and, as a result, long-term viable development of the region. At the same time, a risk of transboundary transfer of technogenic pollutants from one country to another, regular violations of the natural resources management standards in one of the countries, and lack of the sufficient information can impair the achievement of sustainable development in the transboundary region as a whole. All of the above-mentioned points are of great relevance for the countries and groups of countries included in various transboundary regions of East Asia.
Depending on how many countries border a transboundary sea (river), one can carry out specific zoning programs. This will determine a overlapping of influence zones and geopolitical interests of two, three or more countries within one transboundary region. Thereupon, we have identified the following types of the transboundary     (Baklanov 2000). East Asia, mainly in its transboundary regions, is characterized by the presence of zones of international tension and geopolitical problems related to unresolved borders, some of which are remaining legacies of the World War II. In particular, there is a certain unsettledness with regard to differences in positions and related geopolitical tensions between DPRK and the Republic of Korea, between PRC and Taiwan, as well as a number of geopolitical problems associated with the ownership of individual Pacific islands (Table 4).
The existence of such zones of tension in the transboundary regions creates significant constraints for sustainable natural resources management and development. The search for compromises and ratification of long-term international treaties are necessary.

CONCLUSION
Many countries and regions of East Asia have significant geographical (including natural-resource, advantages of location and collocation etc.) and geopolitical (transboundary phenomenon etc.) opportunities for longterm development.
Therefore, availability of considerable land-based natural resources and maritime natural resources seas is a favorable geographical factor for nearly all countries of the macroregion. Many of these resources are renewable (biological, forest, land, water, hydro-power, etc.) and thereby foster the long-term sustainable development of the macro-region. At the current stage of development, this macro-region has the highest and steady rates of economic growth in the world. Eastern Asia is characterized by a very high contrast of the key socio-economic indicators of cross-border spaces of neighboring countries: population density, GDP values, and economic density. A steady decrease in the contrast among neighboring countries of Eastern Asia can be an important factor in reducing the level of conflict and the growth of sustainable development.
The most significant geographical limitations to its sustainable development are evident for the northern and northeastern portions of the Russian Far East, as well as the Western Pacific seismic arc. Within other countries, these limitations are less pronounced. Geopolitical tensions, such as territorial disputes, should be removed by diplomatic means, if all countries are to achieve sustainable international cooperation. In general, the transboundary phenomenon that is typical for all regions and countries of East Asia presents favorable opportunities for the long-term development.
The paper was prepared as part of the project No. 18-05-04 under the "Far East" Program of the Far Eastern Branch of the Russian Academy of Sciences.