Sustainability is the process of maintaining change in a balanced environment in which the use of resources, investment direction, technology development direction, and institutional change are all harmonized, and the potential of present and future is improved to meet human needs and aspirations. There is no universal definition of sustainability. In general, sustainability incorporates many aspects of the environment, economy, and society. It also covers a variety of geographic sizes such as ecosystems, regions, countries, and the world. It also has a limited duration. Sustainability includes long-term goals but cannot be planned for thousands of years in the future. We make adaptive decisions to get you as close to the goal as possible. A country’s overall sustainability (OSUS) is a combination of two major components: ecological sustainability (ECOS), and social or human sustainability (HUMS). The ecological input consists of four secondary components: land integrity (LAND), water quality (WATER), air quality (AIR), and biodiversity (BIOD). The human-level components of sustainability are the political side (POLICY), economic well-being (WEALTH), health (HEALTH), and education (KNOW), each secondary component being the organization’s pressure-state-response approach for the economy. Cooperation and Development. Sensitivity analysis plays a fundamental role in decision-making because it determines the impact of changes in decision parameters on system performance. The Sustainability by Fuzzy Assessment (SAFE) model can help decision-makers build sustainable policies by evaluating sustainability for a variety of development scenarios. Scenarios are defined by available sustainability indicators that primarily reflect the outcome of policies and actions taken over a specific period. As these values change and as a result changes in sustainability are observed, the most important indicators contributing to sustainable development can be identified. SAFE uses fuzzy logic, which does not require an explicit mathematical model to calculate aggregate metrics, and can process both quantitative and qualitative information.