Burn off half of Earth's peat, oil, and gas supplies that have been sequestered over the past billion years. Burn it over a 100-year period, and see if Earth warms some.
Oh, wait: we already did that. :-\
Less than 3% of the global energy reserves have been "burned" (and you forgot coal)
The oldest fossil fuels are from The Carboniferous Period occurred from about 360 to 286 million years ago. (not "a billion")
More energy is locked up in gas hydrate under the oceans than we have burned since man discovered fire.
And at any time prior to the age of man, up to 20% of the dry land was being consumed by massive forrest and grass fires - replenishing the CO2 for the rest of the world's plants to "breathe"
Science is rational, not emotional.
And just how do you know that we've used HALF of the earth's supply of fossil fuels? Is there any scientific way to determine that, given we haven't even explored in many vast areas of the globe?