The global economy is currently undergoing unprecedented uncertainty due to a series of complex and diverse external shocks and risk factors. The COVID-19 pandemic that began in 2019 caused the most severe economic crisis since the Great Depression, leading to a sharp contraction in global economic activity. In response to this crisis, governments around the world implemented fiscal and monetary policies on an unprecedented scale. While these measures helped stabilize markets in the short term, they also triggered side effects such as soaring asset prices and rising levels of public and private debt.

The war between Russia and Ukraine, which broke out in 2022, dealt a major blow to the global supply of energy and raw materials, further intensifying inflationary pressures worldwide. In response, central banks shifted from accommodative to tightening monetary stances, which in turn contributed to a slowdown in global growth. The Israel–Hamas conflict in 2023 deepened instability in the Middle East, adding yet another layer of uncertainty. Although inflation has begun to stabilize since mid-2024, geopolitical risks and asset price volatility remain key threats to global economic stability. At the same time, the intensifying strategic rivalry between the United States and China is accelerating the fragmentation of the global economy. Their competition for technological dominance is reinforcing protectionist measures in advanced sectors and triggering a restructuring of global supply chains.

This study seeks to analyze the relationships between economic fragmentation, global business cycles, and key macroeconomic flows such as trade and foreign direct investment, with particular attention to the evolving dynamics shaped by recent global disruptions. Excluding the introduction and conclusion, the study is composed of four main chapters. Chapter 2 examines the degree of real GDP synchronization among 45 major economies using a Bayesian Dynamic Factor Model. The findings show that global factors had a significant influence on national economies prior to the pandemic, but their importance diminished in the post-pandemic period, with regional factors playing a more prominent role. Differences in recovery speeds and synchronization patterns became more pronounced across regions—namely Europe, North America, and Asia. Europe experienced a slower recovery due to overlapping pressures from the energy crisis and inflation. North America, by contrast, achieved a rapid recovery through aggressive fiscal and monetary stimulus but faced mounting inflationary burdens. In Asia, recovery speeds varied widely across countries, influenced by China’s growth slowdown and divergent policy responses. These differences are interpreted as being driven by variations in national economic structures and policy choices, indicating a strengthening of country-specific dynamics. In particular, factors such as fiscal capacity, industrial structure, and labor market flexibility played critical roles in shaping each country’s crisis response and recovery path.

Chapter 3 assesses the impact of energy price shocks on the Korean economy using a small open-economy New Keynesian Dynamic Stochastic General Equilibrium (DSGE) model. This model is distinguished by incorporating features such as household heterogeneity, capital-investment decision-making, climate-related economic structure, energy consumption as part of household utility, and the role of fiscal authorities. The analysis finds that rising energy prices significantly increase consumer inflation and reduce real household income, leading to contractions in both consumption and investment, and ultimately weakening production and employment. These effects are especially severe among low-income households, given their higher share of energy expenditures. In terms of monetary policy response, interest rate hikes based on the Taylor rule are effective in curbing inflation but risk further suppressing aggregate demand and overall economic activity. By contrast, the Ramsey optimal monetary policy supports economic activity by stimulating consumption and investment through interest rate reductions. Additionally, reductions in fuel taxes help to ease inflation, alleviate consumption declines among constrained households, and reduce the upward pressure on interest rates, thereby helping to prevent a broader economic contraction.

In Chapter 4, the study evaluates the impact of the U.S.–China trade conflict using a general equilibrium model that includes multiple industrial sectors. The analysis assesses the effects of increased U.S. tariffs on imports from China and explores the resulting changes in trade balances under a comprehensive trade war scenario. The findings indicate that U.S. tariff hikes meaningfully altered Korea’s trade patterns with both China and the United States. Based on the assumption of balanced trade, the U.S. attempt to restructure global supply chains resulted in welfare losses across many countries, including the U.S. itself. Korea’s welfare loss was relatively smaller than those of China and the U.S., but still significant. Moreover, the impacts of the tariff war varied across industries. While the petroleum sector was projected to contract, sectors such as machinery, medical and office equipment, electronics and telecommunications equipment, and automobiles were expected to demonstrate relative resilience. These outcomes are attributable to differences in global value chain integration, substitutability, and technological sophistication across sectors.

Chapter 5 analyzes trends in foreign direct investment (FDI) and the role of geopolitical distance from 2013 to 2023. The analysis shows that greater geopolitical distance—measured using ideal point distances from political science—was associated with reduced FDI flows, and that this negative relationship has grown stronger over time. Coefficients were estimated using the Pseudo Poisson Maximum Likelihood (PPML) method. The effect of geopolitical distance was found to be statistically significant for the U.S. and its Western allies. However, in the case of Korea, China, and Japan, the significance was lower, or even reversed in some cases. These results reflect the high degree of economic interdependence and the complex geopolitical relationships in East Asia, suggesting that the influence of geopolitical distance on FDI can vary significantly depending on the region or industry. Accordingly, there is a need to formulate FDI policies that take into account sector-specific characteristics.

Based on these findings, the study presents the following policy implications. First, with global factors weakening and regional influences strengthening, it is important to enhance economic cooperation within the Asia region and promote the stabilization of regional supply chains. At the same time, maintaining policy flexibility is crucial for rapid and effective responses to future economic crises. Second, in the face of rising energy prices, coordinated use of monetary policy to ensure price stability and fiscal policy to support economic activity is required. Special emphasis should be placed on supporting low-income households and advancing energy efficiency initiatives. Third, in response to U.S.–China tensions, it is necessary to adopt customized industrial strategies that reflect heterogeneous impacts across sectors, while strengthening competitiveness and technological protection in industries where comparative advantages exist. Lastly, regarding FDI, long-term strategies should include the management of geopolitical risks, diversification of investment destinations to emerging markets, and enhanced global cooperation in advanced technology sectors. In particular, it is urgent for Korea to establish an FDI strategy that reflects its unique geopolitical position and ensures competitiveness in strategic and high-tech industries.