Yazar "Ursavaş, Uğur" seçeneğine göre listele

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    Convergence analysis of ecological footprint at different time scales: Evidence from Southern Common Market countries
    (Sage Publications Ltd, 2023) Ursavaş, Uğur; Yılancı, Veli
    This study investigates the convergence in ecological footprint per capita across Southern Common Market countries over the period 1961-2016 within the framework of the environmental convergence hypothesis. However, unlike the existing literature, which mainly tests the convergence for the overall period, this study follows a different path. First, the time series is decomposed into different frequencies using the discrete wavelet transform method. Then, using the Fourier Augmented Dickey-Fuller and Augmented Dickey-Fuller unit root tests, convergence in ecological footprint per capita is tested for different time scales; short-run, medium-run, and finally long-run. The results indicate that countries show different convergence tendencies at different time scales. While the results support the convergence hypothesis for all countries in the short-run, the convergence hypothesis holds for only four and three of the five countries in the medium and long-run, respectively. Besides, the results show that the convergence hypothesis holds for only Uruguay for the whole period.
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    Dynamic relationship between carbon emissions and climate policy uncertainty: a dynamic symmetric and asymmetric fourier causality analysis
    (Gheorghe Asachi Technical University of Iasi, Romania, 2023) Yılancı, Veli; Ursavaş, Uğur
    This paper tests the causal link between climate policy uncertainty (CPU) and carbon dioxide (CO2) emissions in the United States from April 1987 to February 2022. In this paper, we use a novel CPU index recently developed and employ a novel econometric methodology, dynamic symmetric and asymmetric Fourier causality tests. The findings of the causality tests show a symmetric causality relationship from CO2to CPU, and a unidirectional causality runs from positive shocks of CO2to positive shocks of CPU. We also run the causality test in a dynamic framework to test the instabilities in the causality relationship. The dynamic symmetric causality test results show a significant unidirectional causality from CO2(CPU) to CPU (CO2) for specific periods. Since different shocks may affect the causality relationship, we test the causality relationship by considering positive and negative shocks. The asymmetric causality test results show a significant unidirectional asymmetric causality from positive shocks of CO2(CPU) to positive shocks of CPU (CO2) for certain periods. Finally, the asymmetric causality test results also show a unidirectional asymmetric causality from negative shocks of CO2(CPU) to negative shocks of CPU (CO2) for certain periods. Based on our results indicating a significant causal link between CPU and CO2, governments and policymakers should avoid policies and decisions that may lead to such uncertainties.
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    Uncertainty and diversification: Analyzing the impact of energy-related and climate policy uncertainties on environmental degradation in the United States
    (Elsevier, 2025) Yılancı, Veli; Ursavaş, Uğur; Yasin, İftikhar
    This study examines the complex relationship between environmental degradation, energy-related uncertainty (EUI), climate policy uncertainty (CPU), and energy consumption diversification (ECD) in the United States from January 2001 to September 2022. Employing novel and robust econometric methods, including the Bootstrap ARDL Bounds test with smooth and sharp structural breaks, the Toda-Yamamoto causality test with a Fourier function, and partial wavelet coherency analysis, the study reveals a surprising negative relationship between both EUI and CPU with CO2 emissions which suggests that uncertainties surrounding energy and climate policies may incentivize actors to adopt cleaner technologies and prioritize emission reduction strategies. However, the study also identifies a positive relationship between ECD and CO2 emissions, highlighting the need for strategic diversification prioritizing renewable and low-carbon sources. These findings emphasize the critical role of clear, consistent, and sustained climate policies in fostering clean energy investment and mitigating environmental degradation.