Changing what we buy is an essential part to the long term plan of actually saving our planet, our resources, and our animals. By purchasing certain products, we often inadvertently support behaviors and acts, that if we were aware they were going on, we would definitely not stand for.
These atrocities take on such forms as violently sheared sheep, whose wool makes the clothing we wear; to the deforestation of the rainforest for palm oil, destroying the ecosystems and habitats of countless species; to commercial long-lines and gill nets, which slowly and painfully kill, not only the fish they are meant to catch, but thousands of other marine animals.
These are a few of the many issues, and they only gets worse. The supply-chain/origination-points of the products we use and the food we consume can be near impossible to determine, as there is very little focus on transparency. But that has slowly started to change. Packaging and labels on many products now include tags or disclaimers letting you know that the items were responsibly sourced or humanely raised/harvested.