Carboniferous period

This period in the late Paleozoic is best known for its insanely high carbon dioxide levels. The levels in Earths atmosphere were about 15,000 parts per million, which when compared to todays levels that are on average 400 parts per million.

Becuase of these really high levels of carbon dioxide in the atmosphere it cause organisms and plants to get really big

The insects during this time grew to insane sizes which in todays world would terrorize people seen in the picture above on the left is known as the Arthropleura armata. This organism grew up to 8 feet in legth and 1.5 feet in width according to Pizzoferrato. The organism on the right is known as the Pulmonoscorpius kirktonensis which grew up to 8 feet long and belonged to the scorpion family.

The carbon dioxide levels also affected the plants and trees during this time as well, it is said that if you were to see a tree during this time you would not even recognize it as a tree or even be able to tell what it is. The trees grew up to 30 meters high and 1.5 meters in diameter. This time was also knows for swampy forest which were everywhere during the time. After these swampy forest eventually died, millions of years later led to the spawn of vast coal deposits. It is also known that 90% of the coal deposits we have today were created during this single time period.

https://owlcation.com/stem/The-Carboniferous-Period-When-Giant-Insects-Ruled-the-Land-and-Sky

https://ucmp.berkeley.edu/carboniferous/carboniferous.php