Has fire existed on earth for billions of years?

Answer 1

Fire was among the first sources of light and heat on Earth's surface (apart from the Sun and lightning). Fire, however, is an oxidation reaction, so actual fire would have been very limited, even in volcanoes, until the Earth had considerable free oxygen in its atmosphere. This occurred around 3.5 billion years ago when the first one-celled plants appeared. There was no coal or oil to burn, and no biomass fuels such as wood, until much later. The earliest fires would have been from heated metals in magma, when exposed to the oxygen released by early cyanobacteria in the oceans.

Answer 2

Fire as a chemical reaction process has been present on Earth for millions of years, with evidence of wildfires dating back to the time of early land plants, roughly 420 million years ago. While the specific conditions needed for fire may not have existed for billions of years, the concept of combustion and the utilization of fire have been integral parts of Earth's history for a significant amount of time.