Environmental impact assessment of China’s primary aluminum based on life cycle assessment

Assessing and accounting for material consumption and environmental impact are necessary to measure environmental externalities of the aluminum industry and to construct an ecological civilization.In this research,life cycle assessment(LCA)theory was used to assess the environmental impact of primary aluminum based on the lime soda Bayer process and different power generation modes,and the sources and distributions of the four selected impact categories were analyzed.The results show that,(1)Negative environmental impact of aluminum industry generally occurs from alumina extraction,carbon anode fabrication and electrolysis,particularly electrolysis and alumina extraction.Primary energy demand(PED),water use(WU),global warming potential(GWP)and freshwater eutrophication potential(FEP)are main environmental impact categories.(2)The environmental load with thermal power is higher than that with hydropower,e.g.,for the former,the greenhouse gas emission coefficient of 21800 kg CO2 eq/t(Al)will be generated,while for the latter,4910 kg CO2 eq/t(Al)will be generated.(3)Both power mode methods reflect the energy structure,whereas direct emissions reflect the technical level,indicating the potential for large energy savings and emission reductions,and some policies,related to clean power,energy efficiency and technological progress,should be made for emission reduction.

Influence factors of international gold futures price volatility

Based on the commodity property and finance property of gold in the international gold futures market,the influence factors of international gold futures price volatility are analyzed from the perspectives of supply and demand factors,financial factors and speculation factors.The structural vector autoregression(SVAR)model is applied to investigating the direction and strength of the effects of influence factors on the international gold futures prices and the variance decomposition approach(VDA)is used to compare the contributions of these factors.The results show that the supply and demand factors still play a fundamental role in the international gold futures price volatility and the role of“China’s gold demand”is exaggerated.The financial factors and speculation factors have significant impacts on the international gold futures price volatility,which reflects that the financial property of gold becomes increasingly important.Governments and investors should pay close attention to the financial property of gold futures.

Time-varying impact of political risk on copper prices

Using the International Country Risk Guide(ICRG)index to represent countries’political risk,the time-varying effect of political risk on copper prices was examined based on the time-varying parameter structural vector autoregression with stochastic volatility(TVP-SVAR-SV)model.The empirical results show that the impact of political risk on copper prices is time-varying and has tended to increase gradually in recent years.There are significant country-level differences in the impact of political risk on copper prices.Political risk has a stronger and longer-lasting impact on copper prices in exporting countries.In terms of risk sources,external and internal conflicts contribute most to international copper price fluctuations in the sample period.The impact of political risk on copper prices reaches an extreme level during the international financial crisis,the European debt crisis,and the election of Donald Trump.

Nonlinear correlation between RMB internationalization and nonferrous metal prices

The correlation between Renminbi(RMB) internationalization and nonferrous metal prices was studied using the nonlinear Granger causality test and the dynamic conditional correlation-generalized autoregressive conditional heteroskedastic(DCC-GARCH) model. The results indicate that the relationship between RMB internationalization and nonferrous metal prices reflects a complex nonlinear mechanism. There was no mutual influence between RMB internationalization and nonferrous metal prices prior to the trials of the RMB settlement in the cross-border trade in July 2009. Since then, however, a bidirectional causal relationship between RMB internationalization and the price of copper and a unidirectional causal relationship from the price of aluminum to RMB internationalization were examined. In addition, due to the impact of extreme events, such as economic and financial crises, RMB internationalization and nonferrous metal prices are not always positively correlated but are rather occasionally negatively correlated.

Spillovers among China’s precious and industrial metals markets:Evidence from higher moments and jumps

This study reveals the time-varying spillover effects of higher moments(realized volatility,realized skewness and realized kurtosis)and jumps between China’s precious metals and industrial metals markets.Using 5-min high-frequency data from May 10,2012 to October 21,2021,the dynamic effects of spillovers are uncovered using the time-frequency domain spillover index framework.The results show that the system connectedness weakens as the moment order gets higher whereas the total jumps connectedness is the smallest,and the spillovers of all estimators are more evident in the short term.The overall information spillovers are time-varying and influenced by major market events.Specifically,for realized volatility,copper is the largest net transmitter and silver is always a net transmitter,while zinc is the largest net receiver.For realized skewness,copper is the largest net transmitter and silver is always a net transmitter,while lead is the largest net receiver.For realized kurtosis and jumps,copper is the largest net transmitter,while aluminum is the largest net receiver.Overall,copper and silver play dominant roles in China’s precious and industrial metals markets system.