33 thoughts on “The Day The Dinosaurs Died”

  1. I’m fairly innumerate, so I need someone to explain the arithmetic to me:

    “More than 99.9999 per cent of all living organisms on Earth died…”

    “About seventy-five per cent of all species went extinct…”

    How exactly does that work? The 25% of surviving species represented by the 0.0001% surviving organsisms? And what about the 30% of forests that did not burn down? Were the other forests that dense? Duhh…

    1. You have to kill all the members of a species to render it extinct. Just a few survivors can save the species. An event that killed 90% of the organisms on Earth would not render 90% of species extinct.

      1. I’m not so innumerate as all that!

        First, there’s such a thing as minimum population viability and density, Noah notwithstanding. It takes more than just a few survivors to save a species, especially under the difficult conditions of the early Paleocene. The numbers I cited below (one million organisms divided among 2.71 million species) suggest an average of 2/5 of an organism per surviving species. Obviously not possible. I think the 99.9999% kill is fantasy. Of the rest, I’d guess the 75% species extinction is *of the known Cretaceous species.* That’s only a few thousand, so it’s 75% of 8+ million/a few thousand species, whatever that number would be. Bacteria are hardy. Most of them would have survived. Also, if 30% of forests did not burn, their inhabitant species would have survived the immediate event. Then, when climate change caused the surviving forests to die back to roots and seeds, animals and plants dependent on full growth would have died off. This is consistent with the fate of birds: The ground and waterfowl of Australia survived, but the forest stem birds went extinct. Re-radiation of the ground birds gave rise to today’s forest crown birds. That’s likely to be the general story worldwide, not the hyperbole in the article.

  2. On seond thought, maybe that sarcasm was a little vague. I was merely pointing out the numbers cited represent breathless hyperbole, not the best idea in science writing, even for New Yorker, and Carl Sagan nothwithstanding.

    But it’s still a good question. Assuming the Cretacous, like today’s world, hosted a trillion organisms divided among 8.7 million species, doesn’t the KT event, as described, leave a million organisms to be divided among 2.175 millions species? What am I not understanding here?

    In passing, not that long ago I read a paper that suggests the Cretaceous ground and water birds of Australia survived the KT event and reradiated from there, which is why we have birds.

    I do support the idea we need to keep an eye on the asteroids and have said so for a long time. “Harvesting the Near Earthers” in Nov. 1989 Ad Astra and the novel “Fellow Traveler” (Bantam, 1991) are both primarily about this stuff. It’s all very well to worry about the rare civilzation-ending catastrophe, but it’d be bad enough to have a rock the size of Yankee Stadium come down on Los Angeles (or anywhere else).

    1. Where did you get only a trillion organisms from? The first estimate I came across was that there are 5 x 10^27 living organisms on Earth today.

      1. OK, your 8.7 million species is eukaryotes only, I’m still skeptical that there are only a trillion eukaryote organisms alive today or immediately prior to K-T.

      2. I got them from whatever bubbled up on a couple of Bing searches, as you’d expect. I just wanted some numbers to toss out to show the sentence in the article was hyperbole:

        “More than 99.9999 per cent of all living organisms on Earth died…” says *no more than* 0.0001 per cent of *all living organisms* survived. That’s ridiculous on the face of it. Even if I used a trillion-trillion organisms in a trillion species, it’s still ridiculous.

        If, as the article asserts, 70% of the earth’s forcests burned, that means 30% of the earth’s forests did not burn, and that places a hard limit on the prompt effects of the impact. And that means the dinosaur populations of those surviving forests must have survived for some little while after the impact. Delayed effects of the impact would have taken some time to evolve (death of surviving forests due to climate change, for example). My guess is, over the next few months or years, populations of larger animals and vulnerable plants went below minimum viable population size and density. But, as we certainly know, enough populations survived that the earth’s biosphere recovered within ten million years (or by the end of the Paleozoic). It’s only the second largest catastrophe of the Phanerozoic, after all. And that in the context that life survived much larger catastrophes in the Precambrian, possibly including the Late Heavy Bombardment, and maybe even the Moon-Forming Event.

        1. An estimate of the number of bacteria is 5×10^30. To get to the most numerous bird species, chickens, you’d have to get into 20 significant figures in the bacteria population before 19 billion chickens even registered.

          The numbers are very problematic. Something that can kill 100% of one species might not even be noticed by some other species. A lazy semi-arctic species that spends half the year on fat reserves might wake up after mass extinction and wonder what knocked over their lawn furniture.

    2. Ants have colonised almost every landmass on Earth. Their population is estimated as 10^16–10^17 (10-100 quadrillion).[27] wiki.
      So total eucaryote population on Earth before K-T was probably a million times more than the figure of a trillion you used

  3. ” a rock the size of Yankee Stadium come down on Los Angeles (or anywhere else).”
    Now there’s an idea. 🙂

  4. Congress would rather build a big monster rocket

    Half of Congress would rather worry about a possible +2 degree temperature rise over the next 80 years, because they believe they have more control over the climate than the ability to build a rocket.

  5. Rand, this is awful science writing.

    DePalma claims to have found the saurian Pompeii? Where a T-Rex was caught in mid-chomp when it got buried alive from the fallout of the asteroid strike?

    Reporter Preston “buried the lede” on that one. A reader has to wade through so much human drama to get to that point.

    Here is how I would have started the article:
    “A young paleontologist may have uncovered a treasure trove of fossil dinosaurs killed in the immediate aftermath of the asteroid strike that brought about the extinction of dinosaurs. Until now, scientists had not located dinosaur fossils anywhere near the geologic layer at the time of the hypothesized impact event, leading many skeptics to reason that the dinosaurs may have died out gradually. The new discovery could be a 65-million-year-old saurian version of the Roman city of Pompeii, where ash from volcano a thousand years ago froze the instant where humans perished.”

    Instead we get this quiche-eating prose
    “If, on a certain evening about sixty-­six million years ago, you had stood somewhere in North America and looked up at the sky, you would have soon made out what appeared to be a star.”


    1. The death of Pompeii and its citizens was in 79 CE, give or take. About 2000 years ago. I knew that.

        1. Btw, it was Pliny the Younger’s reportage. Pliny the Elder is the one who died during recue efforts. And the story ends on a silly note. When the rescuers couldn’t get back off the beach, they had a picnic, and abandoned Pliny the Elder when he collapsed. Current theory is, he was a fat old man and died from a heart attack.

    2. A number of studies I’ve seen investigate — and in conclusion contradict — the idea that the end-Cretaceous extinction event was gradual and long-drawn-out. Here’s one, from Nature (2016): “Macrofossil evidence for a rapid and severe Cretaceous-Paleogene mass extinction in Antarctica.”

      As it says in the Abstract:

      Debate continues about the nature of the Cretaceous-Paleogene (K=Pg) mass extinction event. An abrupt crisis triggered by a bolide impact contrasts with ideas of a more gradual extinction involving flood volcanism or climatic changes. Evidence from high latitudes has also been used to suggest that the severity of the extinction decreased from low latitudes towards the poles. […] We show that the extinction was rapid and severe in Antarctica, with no significant biotic decline during the latest Cretaceous, contrary to previous studies. These data are consistent with a catastrophic driver for the extinction, such as bolide impact, rather than a significant contribution from Deccan Traips volcanism during the late Maastrichtian.


      1. Yes, the article actually discusses that competing hypothesis at one point, briefly. But it seems to be the minority view at present.

        1. Although most everyone is agreed the Chicxulub impact event really happened, and really caused a global catastrophe, it wasn’t one of unparalelled proportion (although near the top of the list!). It behooves us to remember scientists keen on shouting down opposing theories have a career investment in their own preferred theory, and that those careers are embedded in the same Acdemic universe responsible for… well. Pretty much all the nonsense around us today.

          The fact that the two largest extinction events of the Phanerozoic (the ones ending the Paleozoic and Mesozoic) align with the two largest flood basalt eruptions of the Phanerozic (the Siberian and Decan Traps), and that the larger eruption aligns with the larger extinction event and the small eruption with the smaller extinction event, is unlikely to be a coincidence.

          I can’t say this enough: We. Don’t. Know. What. Really. Happened. Maybe someday we will.

    3. Too much journalism takes the form of story telling. I usually just jump to the end and read it backwards.

  6. Here’s a final thought: If 30% of the Earth’s land surface was not immediately devastated by the Chicxulub impact (and ignoring the Deccan Traps problem), then paleotologists should logically examine those areas (as currently known by, for example, the described simulation) in much greater detail. The area right above the KT boundary (the first little while of the Paleocene) is where the rest of the story will be found. It behooves us tp remember the Permian-Triassic Event was MUCH worse than the KT.

    1. Yeah, you can deploy a space force to protect against the Chicxulub impact, and than WHAM!, you get blindsided by a much bigger asteroid on the scale of Permian-Triassic.

      1. Which is why you want Skywarn AND a space-faring civilization. Musk and Bezos want different versions of that future, but it’d be best if we had both.

  7. Whatever the precise percentage of species or organisms killed, one thing that is not in serious dispute is that the Chicxulub impact *did* happen, and that its effects were catastrophic for life on Earth. What’s more important is what the effects would be if it struck today. As David Kring is quoted in the article: “There’s no uncertainty to this statement: the Earth will be hit by a Chicxulub-size asteroid again, unless we deflect it,” he told me. “Even a three-hundred-metre rock would end world agriculture.”

    And what are we doing about it? Something, but not much, at very modest funding levels. NASA has Spaceguard out cataloging NEO’s, and it has made some progress on that front; the DART mission to Didymos in 2021 will conduct a small experiment on kinetic impactors. But in terms of any serious proactive program of detection able to identify even long period and extra-solar objects at distance, and fast reaction planetary defense – which is what is really needed – that is simply not on the agenda.

    Arthur C. Clarke famously founded the premise of Rendezvous with Rama on a major impact event in Northern Italy in the late 21st century which kills hundreds of thousands and obliterates most of the irreplaceable cultural heritage of much of Italy, forcing governments to abandon their previous indifference to the subject of planetary defense. I fear that Clarke was prescient: It probably *will* take a catastrophic event before anything is done about it. Assuming there is any state actor left surviving to do it.

  8. but Congress would rather waste money pretending to build a big monster rockt to keep Shelby’s constituents employed…


  9. This discovery is of a magnitude as if a set of Tutankhamen tombs were discovered as a set in historical context, all with forensic evidence that showed how each pharaoh died.
    The importance of this find cannot be overestimated.
    It is more than mind-boggling.

    Now the effort must be to protect the site from looters and thieves who could do horrendous damage in minutes. Every square centimeter of this small site is precious beyond belief.
    Stand a 24-hour guard.

    John Strickland

    1. If it were on BLM or USFS land, that might be the case. But as the article points out, it’s on remote private property. Land probably owned by people with lots of guns and a willingness to use them on trespassers (and be supported by their local law enforcement.) I wouldn’t be surprised if the locations mentioned aren’t accurate, also.

  10. “This [layer of debris, ash, and soot] is called the KT boundary, because it marks the dividing line between the Cretaceous period and the Tertiary period. (The Tertiary has been redefined as the Paleogene, but the term “KT” persists.) Mysteries abound above and below the KT layer.”

    The biggest mystery to me, by far, is: what the heck does the “K” in “K-T” stand for?

  11. “What is the K-T boundary? K is actually the traditional abbreviation for the Cretaceous period, and T is the abbreviation for the Tertiary period.”
    site: https://www.universetoday.com/39801/k-t-boundary/

    If you use the “correct” term it is now the “KP” boundary, which sounds like army talk for kitchen patrol duty. So we still call it the K-T.
    John S

  12. “And that in the context that life survived much larger catastrophes in the Precambrian, possibly including the Late Heavy Bombardment, and maybe even the Moon-Forming Event.”

    That is unlikely unless your life form can survive in molten rock on a planet with an atmosphere of incandescent rock VAPOR for a long time.
    Several of the late heavy bombardment events were also planet sterilizers. It is also unlikely that bacteria had evolved to live in rock or were living deep in the rock during the Hadean period and that rock would have been much hotter than it is today.
    John S.

    1. Life could have survived such events by being blasted into solar orbit, to return to Earth after things had cooled a bit.

      1. An imaginative person can come up with any number of possibilities. How about a Krypton scenario? Say there was a life-bearing, sealed lava tube somewhere on Earth. The Moon-forming impactor hits and a hung of crust, lava tube, life and all, is ejected safely, then somehow become safely re-incorportayed into the Earth’s crust just when it’s safe to go back in the water (cue Jaws theme…).

  13. Call this a final postscript:

    We don’t have much evidence about what happened during any of these cataclysmic events. What we’re talking about here (including the breathless descriptions in the New Yorker) are primarily the results of simulations and highly theoretical guesswork. If it turns out there’s viable evidence life did somehow survive the Moon-forming impact event, then obviously the simulation that shows the Earth completely melted and supplied with an atmosphere consisting of 50 bar of silica vapor is probably inaccurate. In fact, the Q Machine similation of Chicxulub shows an event that’s far more benign that previous simulations leading to breathless hyperbole about how “looking at the sky would be like looking into a blast furnace.” When a scientist with a career investment in a theory makes a conclusive pronouncement about it, that it with a grain of salt. When a “science journalist” does the same, buy a salt mine. Yeah, the article mentions an important discovery that supports Chicxulub better than previous evidence. And then it launches into Climate Change hyperbole.

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