The carbon dioxide level in the atmosphere will dissipate so much that all plant life dies, and along with it, vegans and vegatarians.
After that it's just a matter of time before us carnivores eat eachother alive.
Should plant life die out then there wouldn't be time for carnivores to eat eachother.
Without plant life there would be no Oxygen recycling, therefore every animal and aerobic bacteria dies of asphyxiation.
The only things left would be those unusual creatures in massive volcanic caves, which live on Sulphur Dioxide, or those similar bacteria which live on deep sea volcanic vents.