Did Dinosaur Gas Contribute to Global Warming?
New research is making the startling claim that enough greenhouse gases were produced by large plant-eating dinosaurs passing wind, for a change in climate to be possible.
Sauropods Are Being Labeled As the Biggest Dinosaur Gas Producers
The culprits were sauropods, a widespread group of vegetarian dinosaurs that lived 150 million years ago. With their typically long necks and tails, this group included genera such as the well-known Diplodocus. At a weight of up to 45 tonnes, and body length reaching 150 feet, Diplodocus is one of the biggest animals to have ever walked the Earth.
Sauropods are now believed to have functioned like large cows, with a system of fermentation in place to assist with digestion, and – like cows – the bacteria produced large quantities of methane.
Dinosaur Gas Caused an Increase in Methane Levels Says Wilkenson
Dr Dave Wilkenson, leader of the study based at Liverpool John Moores University, said that a simple mathematical model has shown that the microbial action involved in sauropod digestion could have generated sufficient levels of methane to make an impact on the climate of the Mesozoic. The research was recently published by Wilkenson in the journal ‘Current Biology’, with Professor Graeme Ruxton of the University of St Andrews, Scotland.
The mathematical calculations even suggest that sauropod digestion could have generated larger quantities of methane than a combination of current natural and man-made sources. As a greenhouse gas, methane is more effective than carbon dioxide and exhibits better heat-trapping abilities.
The researchers became curious about methane-levels present in the Mesozoic during an initial project on the ecology of sauropods. A range of extant species has been studied to determine levels of methane generation, and this baseline has then be used as a predictive tool to determine the amount of methane that animals of various sizes can produce. It turns out that the total body weight of an animal is the determining factor in this equation.
472 Million Tonnes of Dinosaur Gas
Sauropods of medium size weighed in at ca. 20 tonnes, and they are predicted to have lived in herd sizes of up to a few tens of individuals per km2. Using this data, the researchers predicted that ca. 472 million tonnes of methane would be generated globally by sauropods in a year. This figure is similar to modern-day emissions, which is a combination of natural and man-made sources. By comparison, the ruminant animals of today, such as cows, giraffes and goats, produce a combined amount of 45 – 90 million tonnes of methane per year.
Pre-industrial levels of methane emission stood at ca. 181 million tonnes a year. The researchers suggest that sauropod digestion alone may have contributed one to two parts per million towards atmospheric methane concentration. Another four parts per million may have been added by leaks from natural gas fields, as well as forest fires in the wet, warm climate of the Mesozoic. This means that a total methane mixing ratio of six to eight parts per million was entirely possible during the Mesozoic.
Dinosaur Gas = Global Warming
The Mesozoic saw the evolution of increasing size in sauropods, which led to the development of giant species in these plant-eating dinosaurs. They effectively became enormous vessels of microbial activity of the kind that has not been seen since in land animals. Methane was most likely an important factor in greenhouse warming during this era.
The scientists maintain that their ‘simple proof-of-concept model’ points towards a greenhouse warming effect being caused by mega-herbivores such as the sauropods, and that this dinosaur gas may have been important in maintaining warm climates.
