I won’t point at specific people, although it is very tempting to do…
From research it appears that the Earth was up to 10C (18F) warmer in the Mesozoic era, circa 250-60 million years ago. And British Scientists may now have found out why!
With the knowledge that livestock emissions currently contribute to a significant part of global methane levels, the researchers used existing data to estimate how dinosaurs could have affected the climate, with their flatulence! The team of scientist led by Dr David Wilkinson calculated that the total population of dinosaurs must have produced 520 million tonnes of Methane annually, 5 to 10 times the amount emitted by a cow today. Methane gas is known as a "greenhouse gas" that leads to increased temperatures, causing Global Warming.
The BBC article doesn’t reveal what stopped the temperature from further rising back then, but assuming that the root cause of the problem (Flatulent Dinosaur) extincted, it could be worth checking what would happen if we ban onion soup! BBC, Dinosaur gases 'warmed the Earth'