Fuels such as oil, natural gas and coal, are called 'fossil' fuels because they were formed by the decomposition of living organisms over millions of years. Our world today has a heavy reliance on fossil fuels, which unfortunately, has caused a lot of problems. When fossil fuels are burnt, they produce pollution in the form of greenhouse gases. These greenhouse gases contribute to climate change by altering the makeup of our atmosphere. Fossil fuel use is not sustainable. It took millions of years for the fossil fuels to be produced, but humans have used a vast quantity of the world's reserves already, since the dawn of the industrial revolution.
Fossil fuels are various carbon molecules formed as a result of anaerobic (without oxygen) degradation of living matter with deposits taking tens of millions of years to form. The resulting deposits fall into 3 categories, coal, oil and natural gas, from which useable materials can be refined such as petrol, Liquefied Petroleum Gas (aka LPG) and plastics. Their use as fuel releases CO2 into the atmosphere which helps drive climate change and ocean acidification. Climate change is a result of human carbon dioxide and other greenhouse gas emissions exceeding the planets natural ability to absorb them, such as in forests, resulting in the levels increasing. Carbon dioxide retains heat better than many other atmospheric gases effectively acting as a blanket preventing heat from the sun re-radiating back out into space. On top of this one of the major carbon dioxide ‘sinks’ is the ocean, converting atmospheric carbon dioxide into carbonic acid, this has caused the oceans to become more acidic over time and is resulting in mass die offs of many aquatic lifeforms, such as the bleaching of coral reefs.