Ryu Jun-yeol, a famous actor in South Korea, has loved by Koreans of all ages. He first gained public attention through his role in the K-drama, Reply 1988(응답하라 1988) and has made a good impression by appearing a lot of movies that express Korean well such as Little Forest(리틀 포레스트), The Battle: Roar to Victory(봉오동 전투). To youngs, his fashion helped him popular among them as well. 

http://www.allurekorea.com/2018/03/19/i-am-ryu-jun-yeol/

Except for these external things, he is famous as giving social messages to the world. Among them, his the most active and largest action is about the environment. You can check it even through his Instagram profile.

It dates back to his trip to Africa. He had to live a little bit of water for 10 days there. At the dessert, he got found not only the value of water, but it was enough to survive for a person with less water. After that, the Greenpeace was the easiest way to conserve the environment for him. He started to support the Greenpeace from 2016. It was the first action of him for the environment. 

Subsequently, his environmental move continued without ceasing. Above all, there are campaigns with Greenpeace the most. Ryu Jun-yeol's the Rainbow Warrior abroad; Greenpeace's environment surveillance vessel is well known to almost all his fans or environmentalists in Korea. It is meaningful that he was the first Asian celebrity who boarded it. 

https://www.youtube.com/watch?v=rhKqarP4TsY

Plus, to promote Greenpeace's Antarctic Protection Movement to the public, he wrote a column, named 'May Spring Come to the South Pole: Join us in protecting the Antarctic Ocean' in The Huffington Post Korea. Besides, he donated to Greenpeace for particular campaigns like Australian wildfire contributions as well as the regular support. As his independent action without Greenpeace, he narrated a Korean documentary about climate change on EBS1, which is the Korean education channel. He also encouraged people active in the environmental movement by being a model for the April cover of Allure, which was about the environment in 2018.

http://www.allurekorea.com/2018/03/19/i-am-ryu-jun-yeol/

It didn't end with just one man's good. His move spread fast through SNS, and it touched many and make them reflect and practice. The tree-planting movement of Ryu's fan is one of the examples.

I believe the advertisement and marketing are important factors for successful environmental campaigns. If it needs lots of people's participation, it is no use to mention. The choice of Greenpeace with Ryu Jun-yeol as a delegate shows the good results of a good influence on a majority by one celebrity with a good image.

Sometimes, it might be easy to think that the environmental movement is a duty of only environmentalists, for there are only environmentalists in the people for the environment. Of course, the environmentalists are the pioneer to change the world, and they deserve to be praised more than who else. But this severity called the environmental problem is too enormous to confine to solely the environmentalists. Keep in mind that some 'normal' people(=celebrities) are endeavoring to gather power from another 'normal' people(=the public) because of the environment and finally the thing that makes it will be the 'super' power(=citizen participation) from the 'normal's

Sources: https://www.greenpeace.org/korea/press/5307/presslease-ryu-donation-10-million-won/

https://www.greenpeace.org/korea/update/6195/blog-ocean-ryu-allure-interview/