The world inhabited by dinosaurs was typically a hot one, with high levels of greenhouse gasses, lots of water vapor, and no permanent ice sheets. And, according to a new estimate published in the journal Current Biology, the dinosaurs themselves may have contributed to their hothouse conditions.
(Note to the editors of Current BIology: I'm not sure that the Jurassic really qualifies as "current.")
A team of British researchers has put together various estimates of the features of the Jurassic's large herbivores, such as population density, typical body mass, and so on. Combined with an estimate of how much methane is emitted by a typical herbivore, these numbers suggest that the dinosaurs were pouring out enough methane to help the greenhouse effect keep the Earth nice and toasty.