After studying rocks associated with the Great Dying 251.9 million years ago that killed 96 percent of marine species and 70 percent of terrestrial species, Shu-Zhong Shen and others concluded that the extinction was very rapid. The researchers found no evidence of a slow dying off in the 30,000 years prior to the extinction event, and they believe the event might have occurred over just a couple or maybe over a few centuries.* That’s rapid, kinda like the current extinction event we have caused, but ours is spread over tens of millennia, as spear points in mammoth skeletons attest.
Yes, there’s no doubt we’ve done our share of harm to species. “Where’s the Do-do?” we ask. “Where’s the elephant bird?” Not that species don’t go extinct naturally all the time and always have done so, but we’re really efficient at it.
Have natural phenomena done their share of annihilating life-forms? Sure. In his study of the Great Dying, Peter Ward drew a different scenario for the extinction: Increased carbon dioxide coupled with increased atmospheric and ocean temperatures and decreased oxygen.* Ward also argues for a prolonged extinction event, and Shen’s group doesn’t seem to agree with that conclusion. One of the researchers, Ramezani, says that “big changes in temperature come right after the extinction, so we can rule out that ocean temperature was a driver of the extinction.”
And that brings me to what is scary. Here we have reputable scientists studying the same event without agreeing on its cause or its duration. Who’s right? Both Ward and Shen would argue for their conclusions. And while they and others debate the causes of extinction, the clocks of every species on the planet continue to tick. Will we hear the alarm when we’re already late for rising on a new day?
*Shu-Zhong Shen, et al. A sudden end-Permian mass extinction in South China, GSA Bulletin . (2018), Jennifer Chu, Phys.org, September 19, 2018. Online at https://phys.org/news/2018-09-end-permian-extinction-earth-species-instantaneous.html
**Ward, Peter D., Gorgon, New York. Penguin Group: Viking, 2004, p. 226. Ward concludes that the two agents of the extinction were heat and asphyxiation. “Now I am convinced that two things caused the Permian extinction: a sudden rise both in temperature and carbon dioxide near the end of the Permian Period and an equally sudden drop of oxygen in the atmosphere” (224).
Yes, there’s no doubt we’ve done our share of harm to species. “Where’s the Do-do?” we ask. “Where’s the elephant bird?” Not that species don’t go extinct naturally all the time and always have done so, but we’re really efficient at it.
Have natural phenomena done their share of annihilating life-forms? Sure. In his study of the Great Dying, Peter Ward drew a different scenario for the extinction: Increased carbon dioxide coupled with increased atmospheric and ocean temperatures and decreased oxygen.* Ward also argues for a prolonged extinction event, and Shen’s group doesn’t seem to agree with that conclusion. One of the researchers, Ramezani, says that “big changes in temperature come right after the extinction, so we can rule out that ocean temperature was a driver of the extinction.”
And that brings me to what is scary. Here we have reputable scientists studying the same event without agreeing on its cause or its duration. Who’s right? Both Ward and Shen would argue for their conclusions. And while they and others debate the causes of extinction, the clocks of every species on the planet continue to tick. Will we hear the alarm when we’re already late for rising on a new day?
*Shu-Zhong Shen, et al. A sudden end-Permian mass extinction in South China, GSA Bulletin . (2018), Jennifer Chu, Phys.org, September 19, 2018. Online at https://phys.org/news/2018-09-end-permian-extinction-earth-species-instantaneous.html
**Ward, Peter D., Gorgon, New York. Penguin Group: Viking, 2004, p. 226. Ward concludes that the two agents of the extinction were heat and asphyxiation. “Now I am convinced that two things caused the Permian extinction: a sudden rise both in temperature and carbon dioxide near the end of the Permian Period and an equally sudden drop of oxygen in the atmosphere” (224).
RSS Feed