What does ‘fossil fuels represent a huge (but decreasing) store of carbon’ mean, thanks
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Unknown member
Jul 19, 2020
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Hi Charmz,
Could I just ask you to change the name of the post to something like "Fossil Fuels question" as even though this may be from a biology textbook or exam paper, I believe the actual subject matter is closer to physics or geography (with a good helping of chemistry).
In answer to your question, the main fossil fuels are coal, petroleum and natural gas. Fossil fuels such as the above are hydrocarbons - this means the majority of their makeup is of carbon and hydrogen.
The image below shows the chemical makeup of the smallest hydrocarbons - this is some of what is pumped into your parents' car at a petrol station!
The reason these huge deposits of coal just *exist* underground is because life on Earth is carbon-based. This means carbon is the main element found in life - it makes up 45-50% of dry biomass. When plants and animals die, their bodies get covered up by earth over time, which later fossilises them from the pressure. However, after enough mass above them has built up, this crushes even the fossil, causing it to decompose into fossil fuels. Different types of lifeform will decompose into different fossil fuels.
I hope that explains why fossil fuels represent a huge store of carbon. The "decreasing" part refers primarily to our overuse of them in the last few centuries. As I mentioned, fossil fuels take many millions of years to form, and we are using them much, much faster than that. As the image below shows, we don't have that long left using them by any accounts.
Consider that we've only used coal industrially for 250 years or so, and the others only around 50. Many estimates indicate we may be running out within the next half century.
I hope that helped, happy to answer any further questions.
Hi Charmz,
Could I just ask you to change the name of the post to something like "Fossil Fuels question" as even though this may be from a biology textbook or exam paper, I believe the actual subject matter is closer to physics or geography (with a good helping of chemistry).
In answer to your question, the main fossil fuels are coal, petroleum and natural gas. Fossil fuels such as the above are hydrocarbons - this means the majority of their makeup is of carbon and hydrogen.
The image below shows the chemical makeup of the smallest hydrocarbons - this is some of what is pumped into your parents' car at a petrol station!
The reason these huge deposits of coal just *exist* underground is because life on Earth is carbon-based. This means carbon is the main element found in life - it makes up 45-50% of dry biomass. When plants and animals die, their bodies get covered up by earth over time, which later fossilises them from the pressure. However, after enough mass above them has built up, this crushes even the fossil, causing it to decompose into fossil fuels. Different types of lifeform will decompose into different fossil fuels.
I hope that explains why fossil fuels represent a huge store of carbon. The "decreasing" part refers primarily to our overuse of them in the last few centuries. As I mentioned, fossil fuels take many millions of years to form, and we are using them much, much faster than that. As the image below shows, we don't have that long left using them by any accounts.
Consider that we've only used coal industrially for 250 years or so, and the others only around 50. Many estimates indicate we may be running out within the next half century.
I hope that helped, happy to answer any further questions.