Browsing by Author "Romero-Avila, Diego"

Now showing 1 - 4 of 4

Citation - WoS: 5
Citation - Scopus: 8
Are CO₂ Emissions Stationary After All? New Evidence from Nonlinear Unit Root Tests
(Springer, 2022) Romero-Avila, Diego; Omay, Tolga
This study applies a large battery of state-of-the-art nonlinear unit root tests to examine the stationarity properties of carbon dioxide emission series for 28 industrialized countries, five BRICS and seven transition economies over a very long horizon, in some cases over more than two and a half centuries. The application of time-dependent and state-dependent nonlinear unit root tests separately provides mixed evidence regarding the time-series properties of CO2 emissions and a high degree of variability across the different tests. However, the use of hybrid nonlinear unit root tests, combining the presence of structural breaks with symmetric or asymmetric ESTAR adjustment, leads to the rejection of the unit root hypothesis in each of the countries under study with at least one of the hybrid tests. This has important climate policy implications.
Citation - WoS: 1
Citation - Scopus: 2
Convergence of Ghgs Emissions in the Long-Run: Aerosol Precursors, Reactive Gases and Aerosols-A Nonlinear Panel Approach
(Springer, 2023) Romero-Avila, Diego; Omay, Tolga
Anthropogenic emissions of reactive gases, aerosols and aerosol precursor compounds are responsible for the ozone hole, global warming and climate change, which have altered ecosystems and worsened human health. Environmental authorities worldwide have responded to these climate challenges through the 2030 Agenda for Sustainable Development. In this context, it is key to ascertain empirically whether emission levels are converging among the countries forming the industrialized world. In doing so, we focus on 23 industrialized countries using a novel dataset with ten series of annual estimates of anthropogenic emissions that include aerosols, aerosol precursor and reactive compounds, and carbon dioxide over the 1820-2018 period. We apply four state-of-the-art panel unit root tests that allow for several forms of time-dependent and state-dependent nonlinearity. Our evidence supports stochastic convergence following a linear process for carbon dioxide, whereas the adjustment is nonlinear for black carbon, carbon monoxide, methane, non-methane volatile organic compounds, nitrous oxide, nitrogen oxides and sulfur dioxide. In contrast, ammonia and organic carbon emissions appear to diverge. As for deterministic convergence, carbon dioxide converges linearly, while black carbon, carbon monoxide, nitrogen oxides, non-methane volatile organic compounds and sulfur dioxide adjust nonlinearly. Our results carry important policy implications concerning the achievement of SDG13 of the global 2030 Agenda for Sustainable Development, which appears to be feasible for the converging compounds.
Citation - WoS: 21
Citation - Scopus: 26
Convergence of Per Capita Energy Consumption Around the World: New Evidence From Nonlinear Panel Unit Root Tests
(Elsevier, 2022) Romero-Avila, Diego; Omay, Tolga
This paper investigates the existence of stochastic and deterministic convergence in per capita energy consumption among the countries forming four income-level groups and a full sample of 110 countries over the 1971-2019 period. For that purpose, we employ six state-of-the-art nonlinear panel unit root tests with nonlinear dynamics that range from state-dependent nonlinearities such as ESTAR, AESTAR and TAR dynamics to timedependent nonlinearities of structural break form. We find consistent evidence supporting stochastic convergence among high-income and upper-middle-income countries according to two of the six panel tests. Concerning the stronger notion of deterministic convergence, three tests point to deterministic convergence among high-income countries, and only one supports this hypothesis among upper-middle-income countries. Lack of convergence across all country groups carries important policy implications concerning the achievement of SDG7 of the global 2030 Agenda for Sustainable Development that affects every single country in the planet.
Citation - WoS: 4
Citation - Scopus: 5
A Long-Run Convergence Analysis of Aerosol Precursors, Reactive Gases, and Aerosols in the Brics and Indonesia: Is a Global Emissions Abatement Agenda Supported?
(Springer Heidelberg, 2023) Romero-Avila, Diego; Omay, Tolga
This article examines the hypothesis of deterministic emissions convergence for a panel of the BRICS and Indonesia to advanced countries' emissions levels as well as to Sweden (which is a country that has clearly gone through decoupling) using a novel dataset with ten series of annual estimates of anthropogenic emissions comprising aerosols, aerosol precursor and reactive compounds, and carbon dioxide from 1820 to 2018. For that purpose, we employ four novel panel unit root tests allowing for several forms of time-dependent and state-dependent nonlinearity. The evidence supports deterministic convergence following a linear process for carbon dioxide, whereas the adjustment is asymmetric and nonlinear for carbon monoxide. Methane and nitrogen oxides exhibit logistic smooth transition converging dynamics. In contrast, black carbon, ammonia, nitrous oxide, non-methane volatile organic compounds, organic carbon, and sulfur dioxide emissions diverge. These results have implications for the abatement of greenhouse gases emissions at the global level, given the high share of emissions of the BRICS.