What can prove its existence?

`1. Remain of the creature in oceans beds and was turned in to fossils via the environment. 2. Tree rings getting thicker because the environment is getting warmer and wetter 3. The gas levels trapped in ice can show how it has changed over 400 thousand years 4. The temperature has generally been going up at a explosive rate 5. Pollen can be analysed and can show how plants grew 6. History records can show how it was years ago.