In the context of sustainability, the concept of balanced development is crucial at both global and regional levels. This principle is equally significant for specific regions, natural-economic complexes, and local communities. Sustainable regional development necessitates a holistic approach to addressing economic, social, and environmental challenges, which are particularly pertinent at the regional scale. The sustainable development of nations is intrinsically linked to their integration into global processes; however, its resilience and stability are contingent upon balanced regional progress. The West Kazakhstan region exemplifies an economic powerhouse within the country and plays a pivotal role in national regional policy. This study introduces a conceptual model designed to evaluate sustainable development through the balanced interaction of various indicators. The results reveal a disparity between the financial and economic potential of different regions and their environmental challenges. These findings form the foundation for developing a new paradigm of sustainable development that emphasizes the integration of economic growth, social stability, and environmental security. The proposed model has the potential to be adapted in various regions of the world facing similar climatic, water, and social challenges. However, it is necessary to consider local characteristics, data availability, and institutional contexts.

Western Kazakhstan is one of the most climate-vulnerable macro-regions in Central Asia. Intensifying aridification, acute water scarcity, and active land degradation are already undermining its ecosystems and an economy built heavily on oil and gas. Yet investment in the region is still driven by short-term priorities rather than a systematic assessment of actual need. A previous study by the authors identified a significant investment gap for sustainable development in the Aktobe region, and showed that this problem calls for comprehensive, comparative analyses rather than a localized one. This study aims to assess and compare investment needs for sustainable development across the four regions of Western Kazakhstan (Aktobe Atyrau, West Kazakhstan, and Mangystau) for 2021–2024, accounting for sustainability thresholds derived from optimal population density. An improved eco-economic methodology was applied, combining per capita investment need calculations with thresholds indicators of regional vulnerability and adaptive capacity, based on official statistical and sectoral data. The results revealed substantial inter-regional differences in investment needs, driven by differing economic specializations, and pointed to an urgent need for targeted investment in water infrastructure modernization, land degradation prevention, and renewable energy development. A new development paradigm is proposed that integrates sustainability thresholds into investment planning, with region-specific recommendations, offering a reproducible framework for arid regions worldwide. The study’s limitations include its short data coverage period (2021–2024), its reliance on official statistics, and the indirect nature of the population-density threshold. The proposed framework was tested for the hydrocarbon-dependent arid regions of Western Kazakhstan.