In this article we show that mean-adjusting panel and univariate time series unit root tests yield similar size when there is no drift. The conclusion of the empirics for Purchasing Power Parity is that on average it holds

This paper assesses the stochastic convergence of relative CO₂ emissions within three different sets of countries over the period 1950-2013. Using the Local Whittle (LW) estimator and its variants we investigate whether relative per-capita CO₂ emissions are long memory processes which, although...