We extend the dual sourcing model based on the newsvendor framework by considering the environmental impact of transport. In our context, dual sourcing means that a company, e.g. a retailer, uses an offshore and an onshore supplier. We include environmental regulations for transport in the model. Firstly, emission taxes for the transport from the offshore source are considered. It can be shown that with increasing emissions taxes the company sources less from offshore. This improves the environmental performance but the economic performance (expected profit) is severely harmed. Secondly, we propose that an emission trading scheme is valid for transport activities. In this case, the optimal policy turns out to be a two-sided control-limit policy. If the emission limit (expressed in product units) is set to the minimal offshore order quantity the environmental impact of transport can be reduced while the economic performance is nearly not affected. Thus, from managerial perspective emission trading is preferred to an emission tax on transport. Also from the perspective of policy-making emission trading is reasonable as it helps to limit the negative environmental impact of transport but does not strongly reduce the competitiveness of individual companies.

Cooperation among humanitarian organizations has attracted increasing attention to enhance effectiveness and efficiency of relief supply chains. Our research focuses on horizontal cooperation in inventory management which is currently implemented in the United Nations Humanitarian Response Depot (UNHRD) network. The present work follows a two-step research approach, which involves collection of empirical data and quantitative modeling to examine and overcome the coordination challenges of the network. Our interviews with members of the network identified several managerial issues for sustainable cooperative inventory management that the UNHRD network pursues. Using a newsvendor model in the context of non-cooperative game theory, our research has explored member humanitarian organizations' incentive of joining the network, a coordination mechanism which achieves system optimality, and impacts of members' decisions about stock rationing. Our results indicate that behaviors of member HOs do not necessarily align with the UNHRD's expectation. Our results suggest that for system optimality, a system coordinator should carefully assess the circumstances, including demand coefficient and stock rationing. Our research also proposes a policy priority for the first-best system optimal inventory management.

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