Environment: not opportunity cost

In the class, we've learn that opportunity cost is the nest best alternative in a choice, is what you sacrifice to get what you want, the other option. However, for big industries and production centers, environment is not considered as an opportunity cost, because they don't care if they destroy habitats, they only care in selling, in producing money. How have we got into this? We have only one world, and we are destroying it just to gain a profit, and what's worrying is that there's a great amount of firms that do this, just destroying part of the planet to product and sell. What we can do is start to help, and get togetjer in programs that can help our environment, because if not, the world and the nature of it will slowly decrease, at the point in which we can't live in a proper way. But still, it's selfish to destroy part of the world just to obtain money and be succesful in matters of economy, but when the world starts to end, money will be just a paper without a value, monay can't save us, only us. So to keep living the way we have, we need to take caro of our surroundings, and to keep the way it was, if we need to take something from the nature, let's give it back, plant trees for example. There are many ways, let's not fool ourselves, the only thing we need is conscious and motivation.