AT the website of the University of New Mexico we read Research Suggests Large Mammals Influenced Global Climate. Here are some excerpts, with bold added by us:
More than 13,000 years ago, millions of large mammals such as mammoths, mastodon, shrub-ox, bison, ground sloths and camels roamed the Americas and may have had profound influences on the environment according to research in a paper titled, “Methane Emissions from Extinct Megafauna” released in the publication Nature Geosciences Sunday.
Here’s the abstract: Methane emissions from extinct megafauna. Let’s read on:
The extinction of these large herbivores, which also include horses, llamas and stag moose in addition to the giant wooly mammoth, probably led to an abrupt decrease in methane emissions and atmospheric concentrations of the gas with potential implications for climate change says Dr. Felisa Smith, Associate Professor of Biology at the University of New Mexico.
Approximately 13,400 years ago, the Americas supported a mammal fauna that was richer than that of Africa today explained Smith. “Around 11,500 years ago and within 1,000 years of the arrival of humans in the New World, 80 percent of these large-bodied mammals were extinct,” said Smith in the paper.
Humans — you can’t let ’em loose anywhere! We continue:
“This is arguably the first detectable influence of humans on the environment going back 13,400 years to when humans first got to the continent,” said Smith. “I think that it’s intriguing because there are a lot of ramifications. Potentially, if the decrease in methane, which is synchronous with this ice spell, was actually the cause, then humans contributed to the Younger Dryas cold episode.”
We hope you’re paying attention. The Younger Dryas, according to Wikipedia, “also referred to as the Big Freeze, was a geologically brief (1,300 ± 70 years) cold climate period between approximately 12,800 and 11,500 years ago” This implies that the extinction of those large herbivores could have brought an end to what was then a period of global warming.
Here’s more from the University of New Mexico news item:
Herbivores produce methane as a by-product of cellulolytic-microbial fermentation during the digestive process. Enteric emission occurs when methane (CH4) is produced in the rumen as microbial fermentation takes place; most of this is released as burps. Past studies have shown that domestic livestock are an important contributor to greenhouse gas concentrations and can represent ~20 percent of annual emissions.
Burps? Well, those too. Moving along:
The researchers looked at 114 different herbivorous species that were extirpated from the Americas at the end of the Pleistocene epoch. Using ice cores to determine the amount of methane during the onset of the Younger Dryas cooling period, they found the extinction of megafauna closely coincides with an abrupt drop in atmospheric methane concentration.
No burps, no methane. And methane is a greenhouse gas. Are you starting to see where this is going? Another excerpt:
Armed with that information, the researchers then decided to try and determine how much methane was produced by these species. They came up with an estimate of the number of animals and then an estimate of how much methane those animals actually produced. Other animals such as elephant, giraffes and hippos have been studied by putting a gas mask type of apparatus on them to determine how much methane they produce in a day.
Consider, dear reader, that if things had worked out differently in your life, you might have become a master of mammalian methane measurement. While you’re pondering that, here’s one final excerpt from the article:
“We were able to come up with an estimate, which turns out to be about 10 teragrams. This is really pretty enormous,” said Smith. “When you bracket it, at the very minimum, the demise of all these animals explains 12 percent of the decrease in methane seen at this time. At the maximum, it explains the entire decrease. This suggests that the extinction of megafauna by humans caused a detectable impact on the environment long before the development of agriculture and the industrial age.”
The calculations suggest that decreased methane emissions caused by the extinction of New World megafauna could have played a role in the Younger Dryas cooling event.
The lesson is clear. To halt the progress of global warming we must exterminate all remaining mammalian herbivores. Hurry, before it’s too late!
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