The most cataclysmic event to occur in nature?

Answer 1

Hydrogen burining

Answer 2

The most destructive natural event ever to occur on Earth was the Permian extinction event, which occurred about 251 million years ago. A large series of volcanic eruptions called the Siberian Traps erupted for thousands of years. They put so much additional carbon dioxide into the atmosphere, that the average temperature raised by 5 C (9 F). This would've been warm enough for the liquid methane reserves under the ocean to evaporate and float into the atmosphere. Because methane is an even more powerful greenhouse gas than carbon dioxide, the temperature rose another 5 C (9 F) for a total temperature raise of 10 C (18 F). That would have decimated ecosystems worldwide.

Another possible contributing factor could have been a large release of the toxic gas hydrogen sulfide from the ocean floor. This would have poisoned animals and even destroyed the ozone layer, letting in dangerous UV rays.

With or without hydrogen sulfide, the extinction killed off more than 90% of species worldwide. It took 30 million years for biodiversity to recover.

Answer 3

One of the most cataclysmic events in nature is a supervolcanic eruption, such as the one that occurred at Yellowstone around 640,000 years ago. These eruptions release massive amounts of ash and volcanic gases, causing widespread devastation to the surrounding region and on a global scale. The impact on the climate can be significant, leading to long-lasting effects on the environment and possibly triggering volcanic winters.