At the time, the software company pledged to put that money into renewable energy certificates and carbon offset projects that focus on resource conservation.
Now, Microsoft has disclosed 15 diverse initiatives benefiting from the strategy, including biodiversity conservation in Brazil, sustainable agriculture and reforestation in Kenya and a massive wind farm in China.
It is also investing in efforts in India, Peru, Guatemala, Cambodia, Turkey and the United States.
"We looked for projects which might not have happened without the finance from the purchase of the carbon credits," Rob Bernard, Microsoft's chief environmental strategist, wrote on the company's Green Blog. "We've chosen to invest in carbon offsets because, in addition to helping us offset global emissions, our carbon offset strategy also helps us deliver the added economic, societal and educational benefits that Microsoft is already committed to providing around the world."
Here are four of the projects:
Brazil: A collaboration between local communities and NGOs in Brazil's Acre state aims to preserve about 86,500 acres. The Acre Amazonian Reforestation Project supports farming practices focused on growing sustainable profitable crops that don't exacerbate deforestation, organically rearing pigs and using rotational cattle pastures.
Kenya: The Meru Nanyuki Community Reforestation project near the base of Mt. Kenya trains farmers in better land management practices. Members receive annual payments for planting trees that help sequester carbon, while providing them with a source of income for the future in the form of food from fruit, fuel from deadwood and branch trimmings, and medicines from barks. The program also focuses on beekeeping and erosion control. It has more than 53,341 members and more than 6 million trees have been planted.
Mongolia: The focus here is on helping poor households reduce their heating fuel requirements and costs by up to 60 percent through more efficient cookstoves and improved insulation for yurts. Currently reaching 100,000 people, the project planners hope to double their impact over the next three years.
China: The 50 megawatt Chifeng Wind Power Project generates 130,000 megawatt hours (MWh) of energy a year. Over its lifetime, it will help the world's biggest greenhouse gas emitter offset more than 1 million tons of carbon.
All projects selected by Microsoft are independently validated and verified by The Carbon Neutral Company.
Aside from such investments, Microsoft continues to fund ambitious pilots that are testing ways of using powerful analytics software to create smarter, greener buildings without costly retrofits. On its own campus, it already has saved more than $1.5 million in energy costs through this technology.
As of July, Microsoft is the second largest green power user in the U.S. (after Intel) – purchasing more than 1.9 billion kilowatt-hours a year, totaling about 80 percent of its electricity use.