What strategy does Starbucks implement for reducing its carbon footprint in coffee sourcing?

Sourcing coffee from locations closer to roasting facilities is an effective strategy for reducing Starbucks' carbon footprint in coffee sourcing. By choosing suppliers that are geographically closer, the company minimizes transportation distances. This reduction in travel leads to decreased fuel consumption and lower greenhouse gas emissions associated with moving coffee beans from farms to roasting plants.

While utilizing biodiesel in transportation, using electric vehicles, and implementing water-efficient farming techniques are all commendable practices that can contribute to environmental sustainability, they are not directly related to the specific strategy focused on the carbon footprint associated with sourcing coffee. The core of the correct choice lies in the logistics of where coffee is sourced, emphasizing how proximity can play a significant role in environmental impact.