More and more companies are recognizing the value of environmental efforts and changing their business structure’s to be more green. And now, the trend is seeping into social media. Facebook, in an effort to green its social network, agreed to purchase power from a wind farm in Altoona, Iowa, once it’s completed in 2015. The 138 MW farm will supply enough energy to power 100 percent of Facebook’s nearby center in Wellsburg, Iowa, which should help make everyone’s time on the social site a little greener.

But beyond just the social media industry itself, businesses are using social platforms to communicate their green efforts with their followers. In honor of Earth Day, coming up April 22, here are four companies using social media as a tool to go green.

1. NASA

It should come as no surprise that NASA is doing a social media promotion this Earth Day, after all astronauts were the first to capture images of the Earth as a whole. This year, NASA is inviting everyone on the planet to snap a selfie outdoors as part of the agency’s #GlobalSelfie campaign. You can either post your selfie to NASA’s Facebook, Twitter, G+, Instagram or Flickr account or share it on your own account with the tag #GlobalSelfie on April 22. The agency will use the images gathered to create a mosaic image of Earth that will be released in May.

2. Jack Johnson

Musician Jack Johnson and his wife Kim established the Johnson Ohana Charitable Foundation to support environmental art and music education. In honor of Earth Day the organization’s goal is to reduce waste and single-use plastics in schools and communities all over the United States. To reach that goal, Jack Johnson has promoted the organization on his Facebook page, saying the foundation will match up to $25,000 in donations made on DonorsChoose.org.

3. SaveOnEnergy. com

SaveOnEnergy.com is all about saving people money on energy costs. The site itself serves as a place where consumers can shop for lower energy rates, but also has a vast number of tips and tricks to help people save money and reduce their carbon footprints. The same green advice is transferred to its Facebook page. And right now the company is running a promotion to help you offset the energy you do use. By simply liking its Facebook page, SaveOnEnergy.com will donate 100 pounds of carbon emissions on your behalf.

4. Keen

Keen, a shoe company, was founded in 2003 with the mission to work toward building stronger communities and a healthier planet. While its shoes do a lot to enable people to get out into the planet, the company also uses avenues such as social media to promote its environmental agenda. For example, the company recently promoted a campaign on Facebook, Give with Purchase, to help clean up rivers across the United States. Through the end of April, Keen will donate $5 of every pair of shoes purchased to River Network. The proceeds will help fund the KEEN River Clean-up tour, which will occur in 14 different cities.