COVID-19 pandemic, Russia-Ukraine conflict and shale gas development: Evidence from fractional integration.

Although there are papers on the persistence of energy series including the persistence of shale gas, the impact of recent developments such as the Covid-19 pandemic and Russia-Ukraine conflict have been rarely explored in the existing literature. This paper examines the structure of shale gas production in the U.S. by looking at the degree of persistence across different areas, with the aim to determine if shocks in the series are permanent or transitory. Using fractional integration methods (which unlike the conventional methods, allow for the determination of the persistence of energy and non-energy series in a robust manner), and different subsamples that include the Covid-19 pandemic and the Russia-Ukraine war, our results indicate that there is a substantial decrease in the integration order in the total shale gas production in the U.S. as well as in four other plays-Haynesville, Permian, Utica and Eagle Ford. However, no differences are observed with respect to the Russia-Ukraine war. There is another group of four series (Marcellus, Niobrara-Codell, Woodford and Rest of US 'shale') with a very small reduction in the degree of persistence and another group of three series with almost no reduction at all in the order of integration (Barnett, Mississippian and Fayetteville). Several implications in terms of policy are reported at the end of the manuscript.

Inequality Persistence of 21 OECD Countries from 1870 to 2020: Linear and Non-Linear Fractional Integration Approaches.

This paper investigates inequality persistence in a group of 21 OECD countries using linear and non-linear fractionally integrated methods. Using linear models, the results show that the series are strongly persistent which implies lack of average reversal and permanency of shocks. Mean reversion is only found in the case of Finland and partial evidence of mean reversion is detected for Belgium, Greece, Austria and the Netherlands. The results are similar using non-linear methods. Mean reversion is only found in the case of Finland, Belgium, Greece and Spain. Although, most countries show no evidence of non-linear structures except for four countries, namely, Finland, Spain, the United Kingdom and the United States. The implications of the empirical findings are reported at the end of the manuscript.

Persistence and sustainability of fishing grounds footprint: Evidence from 89 countries.

This paper focusses on the examination of the fishing ground footprint in a group of 89 countries using fractional integration. The fishing ground footprint is one of the components of the ecological footprint. Nevertheless, it has not been investigated very much from an empirical viewpoint. We contribute to the existing literature on fishing ground footprint by using fractional integration techniques to examine the persistence of the series. Our results are very heterogeneous across countries though we find that most of the series are nonstationary and non-mean reverting, with most of the countries belonging to the upper-middle and high income levels. On the other hand, most of the 14.4% of countries that show a stationary pattern belong to lower-middle and low income countries. One of the implications of the study is that policies aimed at reducing fishing grounds footprint are likely to be effective in most of the investigated countries.