Economic growth and environment quality: New evidence using continuous wavelet

The relationship between the economic growth and the environment quality and degradation is one of the most debated topics among the economists and environmentalists. Economic growth usually requires more consumption of energy, which leads to more environment degradation. Substituting renewable energy sources for fossil fuels would prevent environment degradation; however, it will hinder the economic growth. Therefore, the relationship between the economic growth and environment could go in both directions and previous studies have shown different results. This study uses time-frequency analysis through wavelet transforms to examine this relationship in Iran using the data from the first quarter in 1991 to the last quarter in 2016. This approach allows identifying the change in the relationship between the variables over different time horizons. To that end, we calculate the coherence and energy of the wavelets over different time horizons using Matlab 2018a. The results show that in the short-run (less than a year) and mid-run (between one and four years), economic growth is the cause of environment and an increase in the economic growth would cause environment degradation. The results from the short and medium run show that this relationship was much stronger during the periods 2012-2015 and 2009-2010. However, in the long run, there is no causality between the two variables so environment regulations would not hinder the economic growth.