In the context of remanufactured products with low production and carbon emission costs, manufacturing firms that produce and sell new and remanufactured products need to choose whether or not to offer trade-in service only for remanufactured products. To address this challenge, this paper investigates the optimal trade-in and warranty period strategies of a firm subject to carbon tax and trade-in subsidies policies. According to the firm’s trade-in choices, we develop two theoretical models: model TIA (Trade-in services are offered for all products) and model TIR (Trade-in service is only available to remanufactured products). The results offer some managerial insights. TIA and TIR may be a firm’s optimal trade-in choice under certain conditions; furthermore, the optimal trade-in service choice is not always benefit consumers. The results show that trade-in strategies have no effect on warranty period strategies, while a firm does not take warranty periods into consideration is more likely to choose TIR rather than TIA. A firm in TIR can curb carbon emissions more effectively. Interestingly, trade-in subsidies are not necessarily conducive to curbing total carbon emissions. We also present several quantitative examples, and find that consumers’ increased acceptance of the remanufactured product does not always benefit the firm.

Recently, consumers have been increasingly shopping due to the development of e-commerce; thus, many traditional firms producing green products are entering e-commerce platforms to sell products for their survival. In the contexts of online sales and carbon tax policy, firms need to determine an optimal carbon reduction level and online return strategies. To address firms’ decision-making challenges, we consider a firm producing and selling its green products via an e-commerce platform. For optimal online return strategies, we find that if the residual value of the returned product is relatively small, the firm should not offer an online return service; otherwise, the firm should offer this service. Moreover, the results show that carbon tax policy is detrimental to the firm and consumers, while increasing the average customer satisfaction rate of the product benefits the firm and consumers. Interestingly, we find that the platform should reduce its referral fee as the unit carbon tax increases.

With the rapid development of low-carbon tourism and online travel agencies (OTAs), whether to enter OTAs has been a problem faced by tour operators in the context of low-carbon tourism. Besides, if tour operators enter OTAs, whether to provide online refund policies is also a challenge for them. To research whether tour operators should enter OTAs and provide online refund policies, three models are built. Main results reveal that when OTAs charge relatively high annual service fees, tour operators should not enter OTAs. When the annual service fees are relatively low and tourist’s satisfaction rate with tour package from online channel meets the constraint in our models, tour operators will enter OTAs and always provide online refund policies for tourists. Although entering OTAs and providing online refund policies will benefit tour operators and tourists, they will cause the worst impact on the environment. Moreover, when considering the impacts of online reviews, government subsidy and discounted value of the dissatisfied low-carbon tour package, operation strategies of tour operators are still held. When considering the different power structure, tour operators’ optimal channel choice strategies are not changed but optimal online refund policy strategies have changed a lot.