The scientific consensus is that the main cause of the extinction was the flood basalt volcanic eruptions that created the Siberian Traps, which released sulfur dioxide and carbon dioxide, resulting in euxinia (oxygen-starved, sulfurous oceans), elevated global temperatures, and acidified oceans.
The level of atmospheric carbon dioxide rose from around 400 ppm to 2,500 ppm with approximately 3,900 to 12,000 gigatonnes of carbon being added to the ocean-atmosphere system during this period.
Several other contributing factors have been proposed, including the emission of carbon dioxide from the burning of oil and coal deposits ignited by the eruptions; emissions of methane from the gasification of methane clathrates; emissions of methane by novel methanogenic microorganisms nourished by minerals dispersed in the eruptions; longer and more intense El Niño events; and an extraterrestrial impact that created the Araguainha crater and caused seismic release of methane and the destruction of the ozone layer with increased exposure to solar radiation.
The thing that is harder to grasp is the scope and scale of the timeline. Like 252 million goes into 4.5 billion nearly 18 times. This means 252 million is recent on the total scale of time. While a similar eruption is impossible within our lifetimes, it will happen again many times in the future.
Won’t actually run out of hydrogen. Only the accessible bit in the core. Most of the hydrogen is in the outer layers and remains untouched. Thus why red dwarfs flare like crazy but Sol, a G-type star does not. Still, we only have around a billion years at Earth’s present orbit until the sun is hot enough that the seas will evaporate. That won’t matter after we live in space stations.
Number 3 of the big 5:
https://en.wikipedia.org/wiki/Permian–Triassic_extinction_event
https://en.wikipedia.org/wiki/Extinction_event
That’s intense
The thing that is harder to grasp is the scope and scale of the timeline. Like 252 million goes into 4.5 billion nearly 18 times. This means 252 million is recent on the total scale of time. While a similar eruption is impossible within our lifetimes, it will happen again many times in the future.
Now consider that the sun is going to run out of hydrogen in ~4.7-5b years and realize that we’re about halfway through this planet’s lifecycle.
Won’t actually run out of hydrogen. Only the accessible bit in the core. Most of the hydrogen is in the outer layers and remains untouched. Thus why red dwarfs flare like crazy but Sol, a G-type star does not. Still, we only have around a billion years at Earth’s present orbit until the sun is hot enough that the seas will evaporate. That won’t matter after we live in space stations.