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How do fossil fuels formed from ancient plants and animals contribute to the carbon cycle?

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Grinnell Glacier shrinkage — Global warming A series of photographs of the Grinnell Glacier taken from the summit of Mount Gould in Glacier National Park, Montana, in (from left) 1938, 1981, 1998, and 2006. In 1938 the Grinnell Glacier filled the entire area at the bottom of the image. By 2006 it had largely disappeared from this view.

Fossil fuels, such as coal, petroleum, and natural gas, are formed from the remains of ancient organic matter—primarily algae, bacteria, and plants—that underwent geologic processes over millions of years. These organisms originally assimilated carbon through photosynthesis, effectively removing carbon from the active cycle and storing it within Earth’s crust as fossil fuels.123

In the context of the carbon cycle, this carbon was sequestered for prehistoric eras, keeping it out of the atmosphere. However, human industrial and agricultural activities now extract and burn these fuels, releasing that stored carbon back into the atmosphere as carbon dioxide (CO₂) and methane at a rapid rate.134

This massive, human-driven influx of greenhouse gases disrupts the natural balance of the carbon cycle. By increasing atmospheric CO₂ concentrations, these emissions enhance the greenhouse effect, trapping heat and driving global warming. It is a fundamental ethical imperative to recognize that this alteration of the Earth's climate systems poses severe risks to ecosystems and human societies worldwide.354