Unburnable fossil fuels
Burning fossil fuels produces carbon dioxide.
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Carbon dioxide emissions need to be limited.
However, the potential carbon dioxide emissions contained in fossil fuel reserves are vast.
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So it's not possible for all current fossil fuel reserves to be used, if the Earth's warming is to be kept below 2 °C.
The chart below is from The Guardian (7 Jan 2015)
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Carbon dioxide emissions need to be limited.
However, the potential carbon dioxide emissions contained in fossil fuel reserves are vast.

So it's not possible for all current fossil fuel reserves to be used, if the Earth's warming is to be kept below 2 °C.
The chart below is from The Guardian (7 Jan 2015)