The winds of change
Like leviathan cows, the mighty sauropods might have generated enormous quantities of methane. Sauropods, recognisable by their long necks and tails, were widespread around 150 million years ago. Scientists believe that, just as in cows,...
Like leviathan cows, the mighty sauropods might have generated enormous quantities of methane.
...our calculations suggest that these dinosaurs could have produced more methane than all modern sources put together
Sauropods, recognisable by their long necks and tails, were widespread around 150 million years ago.
Scientists believe that, just as in cows, methane-producing bacteria aided the digestion of sauropods by fermenting their plant food.
“A simple mathematical model suggests that the microbes living in sauropod dinosaurs may have produced enough methane to have an important effect on the Mesozoic climate,” said study leader Dave Wilkinson, from Liverpool John Moores University.
“Indeed, our calculations suggest that these dinosaurs could have produced more methane than all modern sources put together.”
The research is published in Current Biology.
Methane is a more potent greenhouse gas than carbon dioxide, with a stronger ability to trap heat.
Dr Wilkinson and colleague Graeme Ruxton, from the University of St Andrews in Scotland, began to wonder about Mesozoic methane while investigating sauropod ecology.
Research on a range of modern species has allowed experts to predict how much methane is likely to be generated by animals of different sizes.
The key factor is the total mass of the animal. Medium-sized sauropods weighed about 20 tonnes and lived in herds of up to a few tens of individuals per square kilometre.
Global methane emissions from the animals would have amounted to around 472 million tonnes per year.
The figure is comparable to total natural and man-made methane emissions today.
Before the start of the industrial age, about 150 years ago, methane emissions were around 181 million tonnes per year.
Sauropods alone may have been responsible for an atmospheric methane concentration of one to two parts per million (ppm).
In the warm, wet Mesozoic, forest fires and leaking natural gasfields could have added another four parts per million.
“Our simple proof-of-concept model suggests greenhouse warming by sauropod megaherbivores could have been significant in sustaining warm climates,” the scientists wrote.
Sauropod facts
• Fossilised remains of sauropods have been found on every continent, including Antarctica.
• The name Sauropoda is derived from Greek, meaning “lizard foot”.
• Thousands of 70 million-year-old sauropod eggs were found in a mudstone rock in Argentina a few years ago.