“…Besides, the changes in energy costs might affect demand for energy, which may, in turn, affect the prices of carbon futures. Second, natural gas futures are widely used in energy economics research (Chen et al, 2019; Niu & Wang, 2017; Pouliasis et al, 2020), so this study selects European natural gas prices. In addition, the Port of Rotterdam is the most important and largest logistical center in the EU, so the Rotterdam coal futures price is selected for this study.…”