For the next 10 days, Apple will send proceeds from 27 popular apps in the App Store to the World Wildlife Fund (WWF) as part of what it's calling "Apps for Earth." The list includes mobile games like Angry Birds 2 and SimCity BuildIt, camera app VSCO, and messaging service Line. Some apps on the list are free, so Apple says the WWF will also receive proceeds from in-app purchases as well.

The environmental initiative builds on the iPhone maker's commitment to causes like climate change and conservation. CEO Tim Cook has become more vocal about those issues and other social and policy causes over the past few years as he's taken on a more outspoken advocacy role as chief executive.

For instance, Cook gave time during the company's March product reveal to Apple's Lisa Jackson, the former EPA director and now the company's vice president of environment, policy, and social initiatives. Jackson talked about sustainability and revealed that 93 percent of Apple's facilities now run on renewable energy. The company also partnered with the WWF back in May 2015 to help protect forests in China that are used to make its product packaging, and it's working on a 1,300-acre solar farm to power its new headquarters.