Identifying risk transmission in carbon, energy and metal markets: Evidence from a novel quantile frequency connectedness approach

The carbon, energy, and metal markets are intricately interconnected, and clarifying their relationships is crucial for promoting sustainable development. This paper explores the risk transmission mechanism of carbon, energy and metal markets, as well as portfolio diversification. The quantile frequency framework and portfolio strategy are employed. Our empirical results indicate that the spillover effect is particularly pronounced in bearish and bullish markets. The connectedness of the carbon-energy-metal system is time-varying and cyclical, with short-term effects dominating. Moreover, the metal markets, especially copper, possesses greater explanatory power, and the carbon market is becoming increasingly connected with other markets in the post-COVID-19 period. In addition, the state of market dependence suggests that energy and metals can provide a better hedge against carbon in the medium and long term. Investors are recommended to hold more metals in their portfolios rather than carbon and energy, and to adjust portfolio allocations and hedge positions in response to market situations. Overall, these findings are of great significance for investors building diversified investment and for policymakers monitoring risk contagion.