Starbucks Coffee, Seattle, is offering a one-day promotion to encourage consumers to opt for reusable cups. On Thursday, April 15, global Starbucks locations will reward customers who bring a reusable tumbler into participating stores with a complimentary brewed coffee.

The company’s Shared Planet commitment to environmental stewardship includes a goal to ensure 100 percent of its cups are reusable or recyclable by 2015. In 2009, more than 26 million beverages were served in reusable cups in its company-owned stores in the United States, Canada and the United Kingdom, according to Starbucks’ Global Responsibility Report. This number kept approximately 1.2 million pounds of paper out of landfills, the company said.

“While our cup has become an integral part of the coffeehouse experience over the years, it has also become an environmental concern,” said Ben Packard, Starbucks vice president of Global Responsibility, in a statement. “As a result, we’ve set aggressive goals to minimize cup waste through recycling and reusable options, and are collaborating with a wide range of stakeholders to drive meaningful change. In addition to working with cup manufacturers, municipalities and recyclers to make our cups more broadly recyclable, we’re encouraging customers to think about reusable cups the way they think about reusable grocery bags.”

Starbucks has offered customers a discount for tumbler use since 1985. In addition, the company developed an online Impact Calculator, powered by the Environmental Defense Fund, for customers to find out how many trees can be saved through their tumbler use. Customers also can make a pledge to use tumblers every day and encourage others to do so through social media tools such as Facebook.

The company also is working to develop a comprehensive recyclable cup solution. It is collaborating with local municipalities, raw materials suppliers, cup manufacturers, retail and beverage partners, recyclers, non-government organizations and academic experts to improve recycling infrastructures. Starbucks will host its second cup summit in Boston on April 22-23.