Filipinos are not taking it seriously because of many factors. One is experience about it. Many Filipinos know the consequences but they are not taking it seriously because they did not experience it. And even if they experience the consequences, they don't think that it will have significant effects in their personal lives. Another factor is laziness. They tend to let others do it for them or clean the mess that they do. For example, if they dropped litter, they let others clean those mess for them.
To convince them, they need to experience what reality is. They should see what is happening outside of their homes. Parents should help their children to have empathy for others.