May 7, 2012
Dinosaur Farts May Have Caused Prehistoric Warming
Brett Smith for RedOrbit.com
Dinosaurs may have had a silent, but deadly effect on their climate according to new research by scientists at two UK universities.The study, published in the May 8 edition of Current Biology, compared the digestion-related methane production of Mesozoic-era sauropods to modern cows in an attempt to determine a possible impact as the gas ripped into their prehistoric environment.
"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 Dave Wilkinson of Liverpool's John Moores University. "Indeed, our calculations suggest that these dinosaurs could have produced more methane than all modern sources–both natural and man-made–put together."
Against the backdrop of the climate change debate, many scientists have been studying the environmental impact of methane production for years. Microbes within animals´ intestinal tracts aid in the digestion of their diet and produce methane as a byproduct. These researchers have found that methane production of the microbes´ host animal is directly related to its weight.
These previous findings allowed the UK researchers to scale up the methane production of cows, which typically weigh around 1000 pounds. Based on the calculated weight of the typical sauropods , the largest weighing in at about 240 tons, they determined that methane emissions of the ancient beasts to be around 520 million tons. This compares to the estimated production of today´s cattle of between 50 and 100 million tons. Modern methane production that includes manmade sources is estimated to be around 500 million tons.
Methane is known as a “greenhouse gas” because it absorbs the sun´s radiation and the impact of these calculations means the Mesozoic climate was likely warmer because of its effects. Previous research has shown that the Earth was up to 18 degrees higher during this time.
As impressive as these calculations are, Wilkinson added that dinosaurs were not the sole producers of methane at the time.
"There were other sources of methane in the Mesozoic so total methane level would probably have been much higher," he told BBC News.
Studies of mammalian herbivores have found that the larger animals have developed more efficient digestive processes. Food of larger herbivores tends to remain in the digestive tract longer, allowing the animals to maximize the amount of nutrients extracted from their diet. Many of these animals contain ℠fermentation chambers´ that cultivate large colonies of microbes, which assist in digestion.
The impact of methane produced by these herbivores can have a substantial impact on climate. A 2007 report published by the International Panel on Climate Change found that the 100-year global warming potential of methane is 25 times as great as that of carbon dioxide.
Researchers are currently exploring a variety of options for reducing digestion-related methane emissions from cattle and other animals. These solutions include genetic selection, diet modification and grazing management. Interestingly, cattle that eat grain produce less methane than their grazing counterparts; however greenhouse gas production is somewhat offset by pastures´ greater ability to capture CO2 as opposed to the same area used for grain production.