Feedback loops are how the environment reacts to being heated up. The root cause of feedback loops are greenhouse gases because they trap heat in our atmosphere. Think of feedback loops like cause and effect. Greenhouse gases are the cause and how the environment reacts is the effect. Take for example permafrost, which is permanently frozen ground that never thaws, the most serious feedback loop. Greenhouse gases get trapped in our atmosphere and trap heat. This melts some of the permafrost and releases methane stored underneath. The methane then gets trapped in the atmosphere and traps more heat. This melts more permafrost and releases more methane. This is what is called a feedback loop.