Reducing the carbon footprint of global supply chains is a challenge for many companies. Governmental emission regulations are increasingly stringent, and consumers are increasingly environmentally conscious. Companies should therefore integrate carbon emissions in their supply chain decision making. In this paper, we study the inbound supply mode and inventory management decision making for a company that sells an assortment of products. Stochastic demand for each product arrives periodically and unmet demand is backlogged. Each product has two distinct supply modes that differ in terms of their carbon emissions, speed, and costs. The company needs to decide when to ship how much using which supply mode such that total holding, backlog, and procurement costs are minimized while the emissions associated with different supply modes across the assortment remains below a target level. We assume that shipment decisions for each product are governed by a dual-index policy for which we optimize the parameters. We formulate this decision problem as a mixed integer linear program that we solve through Dantzig–Wolfe decomposition. We benchmark our decision model against two state-of-the-art approaches in a large test-bed based on real-life carbon emissions data. Relative to our decision model, the first benchmark lacks the flexibility to dynamically ship products with two supply modes while the second benchmark makes supply mode decisions for each product individually. Our computational experiment shows that our decision model can outperform the first and second benchmark by up to 15 and 40 percent, respectively, for moderate carbon emission reduction targets.

减少全球供应链的碳足迹是许多公司面临的挑战。政府排放法规日益严格，消费者的环保意识也日益增强。因此，公司应将碳排放纳入其供应链决策中。在本文中，我们研究了一家销售各种产品的公司的入库供应模式和库存管理决策。每种产品的随机需求会定期到达，未满足的需求会积压。每种产品都有两种不同的供应模式，它们的碳排放量、速度和成本各不相同。公司需要决定何时使用哪种供应模式发货多少，例如总持有量、积压量、采购成本最小化，同时与不同供应模式相关的排放量仍低于目标水平。我们假设每种产品的发货决策均受双索引策略的约束，我们为此优化了参数。我们将这个决策问题表述为一个混合整数线性程序，通过 Dantzig-Wolfe 分解来解决。我们根据现实生活中的碳排放数据，在大型试验台上将我们的决策模型与两种最先进的方法进行基准测试。相对于我们的决策模型，第一个基准缺乏以两种供应模式动态运输产品的灵活性，而第二个基准则为每个产品单独做出供应模式决策。