Miri I'm a vegan and the idea you need to understand is that we're not to attempt to live life having no impact on the environment, because that's impossible. The idea is that you make every effort you can to have the least, minimal effect on the environment in the way you live as you possibly can. That includes your modes of transport, your dress, everything you consume and your overall lifestyle.
While I'm aware that I'm using up some of the earth's resources, I do the best I can from educating myself daily about my habits and lifestyle to ensure that I have the least impact on my surrounds as I possibly can.
I purposely never bought a car because of emissions, I walk or bike everywhere I go and if needs be, catch public transport.
I grow my own fruits and vegetables, have a worm farm, recycle and try to eat raw as much as possible. If I want chocolate from time to time, I chose a vegan chocolate (Pana), which I know is fair trade, has no animal product (therefore no animal cruelty) and just as importantly no child slave labour was involved in the production.
We have an anti paper policy at our school, where we photocopy and print as little as we possibly can for our lesson planning to be as environmentally sustainable as we can make it.
The point is, for as long as you live here on earth Miri, you're going to use up some resources. If however you can be as mindful as possible about the way you live your life to maintain God's creation and the health and vitality of yourself and those around you, these are just some of the efforts you can make, and collectively they go a long way to making a significant difference in the world.