Fossil fuels are extremely bad because they bring multiple disadvantages. First, there is a limited supply. These fossil fuels are limited and we don't know when they will end. Secondly, they disrupt habitats. Because they are found underground, this means that when you take them out, there wont be anything to support the other sediments. This can destroy caves, forests might be fragmented which can lead to disrupting other animals life style. Lastly is pollution which is the biggest one.WHen creating fossil fuels, chemicals can run out and cause serious problems. The first one is that when burning fossil fuels you release a lot of carbon dioxide which can increase climate change. Also, chemicals that run out can turn the rain more acidic which can damage any nearby soil and living things.