The Earth spent billions of years without fires until the evolution of oxygen and the appearance of the first large forest fires.
Earth is the only planet in our Solar System that has ever experienced fire. While there may be volcanoes on Venus, the hottest planet, spewing magma onto the surface, an actual fire has never occurred. Likewise, neither on Mercury, nor on Jupiter, nor on any other planet in our solar system or in any other star system has a fire ever developed.
For billions of years of Earth’s history, there was no sign of fires. It took a long period of time before the conditions for a fire could arise, with the planet’s primordial inhabitants living in a fire-free world for an unimaginable period of time.
Although volcanoes could produce fire fountains, as they probably do on Io, and there could be flames from gaseous volcanic eruptions, this was magma sprayed from a fissure, not an actual fire.
About 2.4 billion years ago, Earth’s atmosphere was likely shrouded in a thick methane haze, produced by emerging bacterial life on the planet. Subsequently, the Great Oxidation Event occurred, during which ancient cyanobatteries began producing energy from sunlight, releasing oxygen into the atmosphere.
This event marked the beginning of the accumulation of molecular oxygen in the atmosphere, although initially not in sufficient concentrations to support combustion. The Great Oxidation Event, also known as the Oxygen Catastrophe, brought the Earth into a period of global deep freezing, as oxygen destabilized methane, eliminating it and causing the greenhouse effect to collapse.
The first fossil record of fire dates back to the Middle Ordovician period, billions of years later. There is a sweet spot for the presence of oxygen in relation to fire: if oxygen is less than 13%, plant matter does not burn, if it is greater than 35%, it burns so intensely that forests could not survive.
In the Ordovician period, about 470 million years ago, early land plants such as mosses and liverworts began producing more oxygen, eventually leading to a concentration sufficient to start fires. Around 420 million years ago, the first fossil evidence of fire was found on Earth, represented by the coal present in the rocks of that period.
However, large forest fires did not occur until about 383 million years ago, when oxygen levels reached a stability that allowed large-scale fires to develop. Since then, fires have become a common and often devastating phenomenon.
Links:
