Researchers Discover That Global Mass Extinctions of Land-Dwelling Animals Follow a 27-Million-Year Cycle

Asteroid Hitting Earth

Mass extinctions align with major asteroid impacts and devastating volcanic outpourings of lava called flood-basalt eruptions.

Researchers find that timing of mass extinctions lines up with asteroid impacts and massive volcanic eruptions.

Mass extinctions of land-dwelling animals — including amphibians, reptiles, mammals, and birds — follow a cycle of about 27 million years, coinciding with previously reported mass extinctions of ocean life, according to a new analysis published in the journal Historical Biology.

The study also finds that these mass extinctions align with major asteroid impacts and devastating volcanic outpourings of lava called flood-basalt eruptions — providing potential causes for why the extinctions occurred.

“It seems that large-body impacts and the pulses of internal Earth activity that create flood-basalt volcanism may be marching to the same 27-million-year drumbeat as the extinctions, perhaps paced by our orbit in the Galaxy,” said Michael Rampino, a professor in New York University’s Department of Biology and the study’s lead author.

Sixty-six million years ago, 70 percent of all species on land and in the seas, including the dinosaurs, suddenly went extinct, in the disastrous aftermath of the collision of a large asteroid or comet with the Earth. Subsequently, paleontologists discovered that such mass extinctions of marine life, in which up to 90 percent of species disappeared, were not random events, but seemed to come in a 26-million-year cycle.

In their Historical Biology study, Rampino and co-authors Ken Caldeira of the Carnegie Institution for Science and Yuhong Zhu of NYU’s Center for Data Science, examined the record of mass extinctions of land-dwelling animals and concluded that they coincided with the extinctions of ocean life. They also performed new statistical analyses of the extinctions of land species and demonstrated that those events followed a similar cycle of about 27.5 million years.

What could be causing the periodic mass extinctions on land and in the seas? Mass extinctions are not the only events occurring in cycles: the ages of impact craters — created by asteroids and comets crashing to the Earth’s surface — also follow a cycle aligning with the extinction cycle.

Astrophysicists hypothesize that periodic comet showers occur in the Solar System every 26 to 30 million years, producing cyclical impacts and resulting in periodic mass extinctions. The Sun and planets cycle through the crowded mid-plane of the Milky Way Galaxy about every 30 million years. During those times, comet showers are possible, leading to large impacts on the Earth. The impacts can create conditions that would stress and potentially kill off land and marine life, including widespread dark and cold, wildfires, acid rain, and ozone depletion.

“These new findings of coinciding, sudden mass extinctions on land and in the oceans, and of the common 26- to 27-million-year cycle, lend credence to the idea of periodic global catastrophic events as the triggers for the extinctions,” said Rampino. “In fact, three of the mass annihilations of species on land and in the sea are already known to have occurred at the same times as the three largest impacts of the last 250 million years, each capable of causing a global disaster and resulting mass extinctions.”

The researchers were surprised to find another possible explanation beyond asteroids for mass extinctions: flood-basalt eruptions, or giant volcanic eruptions that cover vast areas with lava. All eight of the coinciding mass die-offs on land and in the oceans matched times of flood-basalt eruptions. These eruptions also would have created severe conditions for life, including brief periods of intense cold, acid rain, and ozone destruction and increased radiation; longer term, eruptions could lead to lethal greenhouse heating and more acid and less oxygen in the ocean.

“The global mass extinctions were apparently caused by the largest cataclysmic impacts and massive volcanism, perhaps sometimes working in concert,” added Rampino.

Reference: “A 27.5-My underlying periodicity detected in extinction episodes of non-marine tetrapods” by Michael R. Rampino, Ken Caldeira and Yuhong Zhu, 10 December 2020, Historical Biology.
DOI: 10.1080/08912963.2020.1849178

30 Comments on "Researchers Discover That Global Mass Extinctions of Land-Dwelling Animals Follow a 27-Million-Year Cycle"

  1. Stop being a fear monger

    • Torbjörn Larsson | December 11, 2020 at 7:09 pm | Reply

      Mass extinction has been observed. The paper attempts (poorly, IMO, see my longer comment on it) to analyze those observations.

  2. How far away from our next extinction in years are we?

    • ScienceTeacher | December 11, 2020 at 9:19 am | Reply

      The article referred to the mass extinction 66 million years ago, but did not mention any more recent. So… does that mean we are long overdue? Or that there was another one more recently? Since the whole purpose is to enable prediction, the article kind of skipped an important point.

      • Torbjörn Larsson | December 11, 2020 at 7:14 pm | Reply

        FWIW, the better paper I reference debt (diversity capital attrition rate) clock and its current is stated in the abstract.

        “A direct test of the time to over-threshold macroevolutionary decay4 (shared fraction of species between two times ≤ 0.1), counted by the decay clock, reveals saw-toothed fluctuations around a Phanerozoic mean of 18.6 million years. As the Quaternary period began at a below-average decay-clock time of 11 million years, modern extinctions further increase life’s decay-clock debt.”

        The Quaternary began 2.6 Myrs ago, so we are down to 8 Myrs and counting, if I understand correctly. But then again, we are – as I think the author’s imply – resetting the clock ourselves.

        The paper here is worthless IMO, so I can’t help you there. I can’t even find the first claimed putative land extinction event anywhere (and they give 5 references to their data).

    • Exactly, 26 million yrs, where we today!

      • Torbjörn Larsson | December 12, 2020 at 5:40 pm | Reply

        Not even if you accept the junk model described here. Their last putative extinction event was 5 Myrs ago, so it would be 21 Myrs to the next one according to that pseudoscience.

  3. I am guessing we are 12 million years from the last one. So there should be another one in about 14 million years. Plus or minus a million obviously.

  4. well now thomas if u had a crystal ball u might be able to tell us
    so lets peer inside it and see
    65 million years ago last mass extinction event
    as our solar sun and planets cycle proper motion direction navigates its way through the crowded mid plane of the milky way galaxy periodic comet showers occur in the solar system as it enters and exits the crowded mid plane of the milky way galactic ancient relic plate disc
    and then as a back up
    gaia will map for u where the solar sun and its closest stars within 100 par secs will be located within the next 400,000 years
    the video is so fuzzy and very unclear and the 3 d is out of sync with the reality of the milky way galactic plane that you could not make head nor tail of it
    but historically if they say the extinction cycle is every 30 million years approximately
    then and only then
    i will inform you
    unless i have missed a major extinction event between 66 million and now
    that we are presently reentering the mid plane of the milky way galactic disc
    and if this be true
    according to the data published above
    the seven oceans are the first to feel the effects of all those other stellar objects in the mid plane ancient relic disc of the ancient galactic disc
    ie by the heat
    and so they evaporate every 26 million years
    and them the land begins to dry out and life begins to find it hard to survive i would reckon hence terrestrial extinction every 27 million years
    but there again thats a solar proper motioin sine wave
    66 million years ago comet crash ie sun in galaxy plate disc
    33 million years ago stellar proper motion at top of its arc curve either above or below the galactic plane
    today 33 million years later descending down re entering through the mid plane of the galactic plane disc
    and it probably will take 5 million years to go through the plane of the milky way disc and exit the far side
    r u ready therefore in the meantimes ahead
    for ocean depletion 500,000 years hence
    followed by terrrestrial extinction 1,500,000 years hence
    followed by volcanic eruptions 2,000,000 years hence
    followed by cometary collisions 2,500,000 years hence
    its all ahead of us
    fail to prepare
    prepare to fail
    unless the position of the solar sun is not at this coordinate point in space and time
    maybe gaia could map it out correctly for us all see correctly with all the stars within 300 parsecs inside the milky way galaxy and not outside it
    and if i be wrong
    where then is the stellar sun location as my crystal ball cracks and breaks and crumbles in a thousand shattered pieces

  5. How is it humanly possible to write an article on mass extinctions every 25 million years and not talk about when we are gonna be do for the next one? How is that even possible?

    • You probably aren’t a subscriber, so you don’t see the full text.

    • Torbjörn Larsson | December 11, 2020 at 7:20 pm | Reply

      It is a press release copy, not a tabloid article (which I noted since so many ask, the tabloid papers for some reason of their own mentioned the last one – so readers can draw their conclusion).

      FWIW, I point to a real science (the one the press release describes looks like poor, bordering on pseudoscience, work) paper below, and give an answer based on that above.

  6. If there is extinction from volcano action
    Why are we seeing more and more intense volcanic activity lately?
    That has nothing at present with any asteroid.
    We are seeing a increase in temperature across the world
    We are seeing the SUN temp increasing
    Now could the rise and effects of the sun becoming to a NOVA (and no one is speaking about this)?
    Then consider we are observing a magnetic pole reversal as well
    That means we are on the cusp of something much bigger than scientists can put together.
    How about a drastic shifting in land masses with the ocean waters suddenly running over the land masses, causing a serious extinction of man?
    Why is the government having built many tunnels underground in the US to hide the elite ?
    So they ca run to safety when we cannot,
    They are not telling us the real facts,
    Just start looking into the research videos at Diehold foundation,
    It may shock you and get you really upset about what is supposedly going to happen when government is wanting to depopulate this world.

    • David,
      You asked, “Why are we seeing more and more intense volcanic activity lately?” I’m not aware that we are. There have been many periods of time in the past when volcanic activity was much greater. Some geologists have even gone so far as to speculate that civilization only exists because we are experiencing a period of low volcanic activity.

      You asked the absurd question, “Why is the government having built many tunnels underground in the US to hide the elite? So they ca run to safety when we cannot” If you had given a moment of thought to this claim, you would have realized that the result of volcanic activity is to either cover the ground with lava, or bury it in ash (such as at Pompeii), or both. Your ‘elite’ would then find themselves sealed in, with no air to breath. Please take your med’s regularly!

    • Torbjörn Larsson | December 11, 2020 at 7:27 pm | Reply

      There isn’t any “unreal” facts, only facts or scams, and scientists endeavor to find them – and succeed, see how transistors, computers, internet and web was discovered by scientists.

      There is no one withholding facts on nature, except in companies short term for market reasons, except in beliefs of conspiracy theorists. Your comment reads like that, and I would guess your link is equally devoid of precisely the facts that you ask for.

      Best case scenario, you withdraw from your conspiracy theory peers and start an education to catch up on what science (and education) is.

  7. We are already in that affected 1/0 membrane has already been damaged pandemic is not just a pandemic the ozone’s that are chemical hand protectors type c and D’s are not as rapid ionization T shellz interferon to neurons our bodies used to rebuild itself same as the ozone’s in our blood to fight off infections nearly half of wildlife is already past carbohydrates random species how they didn’t want to pay attention to that not relevant but it can be seen from the air has one species depitulate

  8. Digital Bookworm | December 11, 2020 at 4:04 pm | Reply

    Asimov wrote something about this over 30 years ago.

  9. I’m sure I read something by Asimov about this more than 30 years ago.

  10. Torbjörn Larsson | December 11, 2020 at 7:05 pm | Reply

    This is a poor paper, where first author Rampino returns to fishing in cloud waters of earlier authors including himself, and that they find the same periodicity from the lumped data as earlier statistically problematic methods did does not bode well.

    In fact, already Alroy could see with event data and doing a perfectly fine autocorrelation that there isn’t any periodicity [“Dynamics of origination and extinction in the marine
    fossil record”, PNAS, 2008]. “Furthermore, the lack of any significant autocorrelation in the data is inconsistent with macroevolutionary theories of periodicity or self-organized criticality.”

    Presumably that is why these authors use poorly defined lumped data (“distinct extinction episodes “) that only covers land originates from one source which is reused over and over.

    For another and much more promising take, see “Impacts of speciation and extinction measured by an evolutionary decay clock”, Nature:

    “Here we apply machine learning to generate a spatial embedding (multidimensional ordination) of the temporal co-occurrence structure of the Phanerozoic fossil record, covering 1,273,254 occurrences in the Paleobiology Database for 171,231 embedded species. This facilitates the simultaneous comparison of macroevolutionary disruptions, using measures independent of secular diversity trends. Among the 5% most significant periods of disruption, we identify the ‘big five’ mass extinction events2, seven additional mass extinctions, two combined mass extinction–radiation events and 15 mass radiations. In contrast to narratives that emphasize post-extinction radiations1,3, we find that the proportionally most comparable mass radiations and extinctions (such as the Cambrian explosion and the end-Permian mass extinction) are typically decoupled in time, refuting any direct causal relationship between them. Moreover, in addition to extinctions4, evolutionary radiations themselves cause evolutionary decay (modelled co-occurrence probability and shared fraction of species between times approaching zero), a concept that we describe as destructive creation. A direct test of the time to over-threshold macroevolutionary decay4 (shared fraction of species between two times ≤ 0.1), counted by the decay clock, reveals saw-toothed fluctuations around a Phanerozoic mean of 18.6 million years.”

    That is a massive data set of 1+ million events, using the best modern method, and they find a decay clock from asynchronous diversification and extinction events that accumulates and spends a diversity capital. That is consistent with Alroy, but not with these “lets use 20 events” extinction models. The statistical power is many orders of magnitude larger, and the methid much better. [I must say I found the name of their discrete reasoning, “circular spectral analysis”, well … circular. :-D]

  11. Leonardo s. Palma | December 11, 2020 at 11:46 pm | Reply

    I hope to believe that mass extinction begins much earlier before huge impact occure in our planet which makes only an extended scenery on how Earth encounter such catastrophic events that nearly wipe-out all livings/reshaping lanscape to our planet? Does our solar system revolved in an eliptical orbit inside the Milkyway Galaxy? which i thought it is not always in uniform track because of distortions meet with-in its traveled path/ eg, radiation events of energy’s from different source, movement of our niegboring stellar make-ups and the influence tug of Universe expanse..its a lot make sense? Now, as probobly were’re entering slum region in the mid plane of our Milkyway galaxy and it is forecasted earlier the forhcoming Meteor shower this December,does this indicates the big-one is coming? Did we had the ability to re-track its path which i think its on experimental stage and not finally tested yet? How can we protect ourselves if does realy its way on us?..I’m so thankful and acknowledge all the selfless efforts and works of those brilliant scientist, astronomer and engineers around the World who join in looking every possibility how to save every life bearing on this planet..more ovious that we are still much-much away to vacate are very own Planet realising that our nieghboring Galaxies are too much far away and invoved so many questions to solve behind.

    • Torbjörn Larsson | December 12, 2020 at 5:42 pm | Reply

      I think you worry unduly – at least on this terribly bad proposal presented in the article, which has no support in observations.

  12. Joseph W DeJesus | December 12, 2020 at 11:56 am | Reply

    The energies that govern existence have already written our destinies.

  13. The mass extinction was the cause of a global flood. The Bible tells us that when the world was flooded, all life, animals, plants, birds, wild beasts etc were destroyed. All layered up in the ground due to the intensity of the flood. All the smaller animals that couldn’t survive the impact of the fountains of the deep that shot through the earth, died first and the bigger, stronger animals last. The sand and the mud covering all life in layers at a time.
    “In the six hundredth year of Noah’s life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened. And the rain was upon the earth forty days and forty nights.” -Genesis 7:11,12
    “And the waters returned from off the earth continually: and after the end of the hundred and fifty days the waters were abated.” Genesis 8:3.
    There was no earth collisions. The flood made so much damage upon the earth, also changed the weather patterns. The amount of water in the atmosphere, causes the cooling of the earth, creating cooler weather, like snow…and hence the ice age. The earth is in a healing state where it’s trying to get back to what it used to be…Eden/Paradise. All the warmer weather, the global warming, is the earth getting back to that state. It’s really not a bad thing to witness. We are witnessing the very creation God created being healed and there is nothing we can do about it. Just sit and watch the wonders and the works God has made. The world God has made was for us to enjoy. How can we enjoy it if the world is in a suffering state? If we suffer with it too? He is the One in control, not us.

    The mass of animals dying are also mentioned in the Bible.

    “Hear the word of the Lord , ye children of Israel: for the Lord hath a controversy with the inhabitants of the land, because there is no truth, nor mercy, nor knowledge of God in the land. By swearing, and lying, and killing, and stealing, and committing adultery, they break out, and blood toucheth blood. Therefore shall the land mourn, and every one that dwelleth therein shall languish, with the beasts of the field, and with the fowls of heaven; yea, the fishes of the sea also shall be taken away.”
    Hosea 4:1‭-‬3 KJV
    And this is the sign of the end of times also and of Christ’s return.

  14. Torbjörn Larsson | December 12, 2020 at 6:48 pm | Reply

    I have now accessed and read the “Impacts of speciation and extinction measured by an evolutionary decay clock”. Nature (2020) paper and FWIW find it impressive data wise and its data derived model intriguing.

    It uses species co-location over time, so the normalized data decay clock is observing a shared fraction of species (co-occurrence probability) or the average decay rate of “macroevolutionary structure”. This supports a Red Queen model of evolutionary rate with an apparently constant change rate from internal and external mechanisms of 18.6 Myrs for the last 0.5 Gyrs of complex species.

    A counter-intutitive result is that the – decidedly asynchronous – mass radiation and mass extinction events (defined by the normalized co-location becoming < 0.1) are both upsetting the constant process rate. To wit, "… evolutionary radiations also cause comparable decay by diluting a pre-existing species set, thereby decreasing the co-occurrence probability …"

    "In this sense, mass radiations (Fig. 3, Table 1) can be as destructive to existing species sets (and potentially, therefore, to the ecological communities within this maximal envelope) as major extinction events. Consequently, the decay clock has been periodically reset throughout Phanerozoic history by both extinctions and radiations (Fig. 2)."

  15. Guy McPherson provided a link to this paper on his website “”, he seemed a bit disturbed, and humbled as he put it, to think that his “ near term anthropogenic climate disruption extinction event” was being overshadowed by this 27 M yr. cycle. For him it seem we are perpetually 2 or 3 years away from total annihilation.

  16. When did the last 27.5 period end?
    12-17.5 milliin years ago? Coinciding with predictive age of the original sphinx? And the message in the pyrmaid at gozer?

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