However, despite appearances, these two worlds are really one, and that means, anything produced or consumed by humans has environmental sources, impacts, and ramifications.
When I am thinking about buying something, I try to remind myself of these considerations. Specifically, I think about what went into the product and what will happen to it after I am done with it. That helps me determine whether the cost to the environment is worth it. For example, if I cannot recycle it and/or its packaging, it's probably not something I want.
An interesting consequence of this kind of thinking is that I end up buying a lot less stuff because by the time I am done, I wonder whether I really need it anyway: All those things that seem cool at first glance start to look frivolous.
If you are looking for a way to remind yourself about these considerations, when you are about to buy something, think "It is (or is near) a rock somewhere." Of course, this is taken from "It's five o'clock somewhere," but hopefully, it helps you remember that the product you are thinking about buying came from some place in the environment, is now in the environment in a different form, and, even after it leaves you, will have a place in the world--perhaps as part of one of those trash islands in the Pacific Ocean.
Using this reminder is a surprisingly easy habit to develop because it starts to become just part of how you think about things. In addition, you'll love how good it makes you feel when you can deny that initial impulse to buy.