In our society today we are very much aware of the effects of greenhouse gases on the climate. Global warming due to anthropogenic pollution has been discussed vigorously over the last decade. We spend enormous amounts of money on research and development of Carbon Capture and Storage, i.e. the possibilities of storing excess carbondioxide underground.
Geologists discuss the causes and effects massive release of carbondioxide or the four times more potent greenhouse gas methane possibly had on the climate and on life on Earth during the end-Permian and end-Triassic mass extinction events.
In a quest to find out what is normal and not normal when it comes to carbondioxide levels in the atmosphere, and the circulation of carbon on Earth, researchers have found out that our domestic cows produce some 50-100 million tonnes methane per year by gases formed in their guts.
Now a team of researchers lead by David Wilkinson have calculated how much methane may have been produced by large herbivorous dinosaurs, the so called sauropods including e.g. Apatosaurus, and their best estimates suggest 520 million tonnes of methane per year. A truly staggering amount as this equals the total combined methane emissions per year from all sources on Earth, i.e. from all animals and all human activities.
Sauropods probably had big guts containing lots of methane producing microbes!
The mean global temperature during the Mesozoic is estimated to have been 10 degrees Celsius warmer than today. Interestingly the Jurassic and Cretaceous periods are in general considered to have been periods of high diversity and productivity, both at sea and on land, despite the high levels of carbondioxide in the atmosphere.
So how come we fear carbondioxide and methane emissions today?
The key issue is probably time. Our planet; its interacting animals and plants, minerals and rocks, needs time to adapt to environmental changes. Fast injection of huge amounts of greenhouse gases to the atmosphere, whether from massive volcanism or from anthropogenic emissions, can shift climatic zones and cause major disruptions in ecosystems.
Perhaps the methane farts from the herbivorous dinosaur populations only sustained the greenhouse climate that was initiated at the end-Triassic?
Perhaps they didn’t really make things worse…just kept things normal?