The Effects and Scale of the Collapse of Regional Economies in Poland During the 2007–2009 Crisis and the COVID-19 Pandemic in the Aspect of Recent Energy Crisis Caused by the War in Ukraine

The purpose of this article is to assess the impact of three major crises—the global economic and financial crisis of 2007–2009, the COVID-19 pandemic (2020), and the energy crisis induced by the war in Ukraine (2022)—on the condition of regional economies in Poland, both before and after their occurrence. These events, which may be regarded as black swan phenomena, were examined using several indicators of regional economic performance: the Herfindahl–Hirschman Index (HHI), the dynamics of Gross Domestic Product (GDP), industrial output sold, construction and assembly output, and retail sales. The study is based on Statistics Poland GUS data ranging from the first quarter of 2004 to the fourth quarter of 2024. The findings indicate that some Polish voivodeships (Since 1 May 2004, Poland has been divided into regions (NUTS I) and voivodeships (NUTS II). In this division, the region is statistical in nature, but in the presented research we refer exclusively to voivodeships, and therefore we also use the terms “region” and “NUTS II” interchangeably in this work. The interchangeable use of these terms also stems from the practice in Polish literature) (regions) experienced increases in industrial concentration over the study period. In 2009, during the global financial crisis, seven regions (Dolnośląskie, Lubuskie, Małopolskie, Mazowieckie, Opolskie, Podkarpackie, and Pomorskie) exhibited a relatively high degree of industrial diversification. Seven others (Kujawsko-Pomorskie, Lubelskie, Łódzkie, Śląskie, Świętokrzyskie, Wielkopolskie, and Zachodniopomorskie) showed moderate concentration. The two eastern regions—Warmińsko-Mazurskie (HHI = 194) and Podlaskie (HHI = 315)—had the highest concentration of industrial production in that year. By 2024, the overall pattern remained consistent: seven voivodeships displayed high concentration, eight moderate concentration, and one (Podlaskie) exceptionally high concentration. The degree of cyclical convergence across regions was generally high throughout the examined period. However, notable differences emerged under crisis conditions. Synchronization was strongest during the COVID-19 pandemic, when abrupt and unexpected shocks produced relatively similar regional responses. In contrast, the financial crisis of 2007–2009 and the energy crisis of 2022 generated more heterogeneous regional effects, resulting in lower and more varied levels of convergence.