The Jurassic was far hotter than today, yet triggered no runaway greenhouse effect


Despite fierce huge meat eating monsters roaming the globe life flourished as never before or since.
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The Jurassic was far hotter than today, yet triggered no runaway greenhouse effect

By Rosco Mac

The best estimates I can find suggest the Jurassic period was up to 10°C hotter than today.

“The Jurassic period is known for a climate characterized by rain-forest-like conditions. Peat bogs that later formed into massive coal deposits existed throughout many parts of the Earth, forming under dense forests. Most of the land is believed to have been productive for plant and animal growth and diversity. Sea levels rose and created warm, shallow-coast environments conducive to coral reef development.

“The Triassic warmth continued into the Jurassic, but the increased humidity levels due to flooded landmasses, as well as increased carbon dioxide levels from the lush vegetation and lack of polar ice, created a “greenhouse” climate. Even the polar regions had a temperate climate.”

Despite fierce huge meat eating monsters roaming the globe life flourished as never before or since.

If ever a “runaway” greenhouse effect were even remotely possible it should have occurred then – but it didn’t and the diversity of plant and animal life was unprecedented.

The arrangement of the continents probably had more to do with the climate than some nonsensical greenhouse effect.

If there were no continental land masses close to the poles the whole world would undoubtedly be warmer due to this alone.


12 thoughts on “The Jurassic was far hotter than today, yet triggered no runaway greenhouse effect”

  1. The mid-Mesozoic (roughly the late Triassic to mid-Jurassic) also had about 10 times the present levels of atmospheric CO2. There is no combination of conditions that are found in climate models to be harbingers of catastrophe that the planet has not experienced already. Not catastrophes have yet ensued from the conditions most troubling to warmist modelers. The sole indicator that actually HAS been accompanied by serious events is too little CO2 (terminal Permian for instance, or the recent glacial epochs).

  2. That’s a good point. Tropical plants in temperate climates not all attributable to continental drift. Why don’t long term climate scientists look back farther than 50 years? They probably should, it hasn’t been warming for half that time.

    1. The situation is sadly complicated in recent direct temperature data, mainly due “adjustments.” Prior to the recent fad for AGW, recorded temperatures were not severely adjusted as far as I can find. The planet really did start warming with the end of the Little Ice Age. That warming “may” have continued, or it may have ended sometime in the last 30 years. During the early AGW push, the assertion was that earlier warming, prior to ca. 1950 or 1960 was “natural” but that after that human output had taken over. Just how that was known was never actually well explained (p*** poor methodological presentation or truly rank scientific reasoning).

      Sadly, the disagreement between theory are reality would not go away and evidently the data needed “adjustments.” Thanks to these “adjustments” we can’t be sure just what has really been going on because earlier studies are incommensurate with later analyses. There are strong indications that most of the recent “warming” is due to these adjustments. You will see various writers point out the BEST data shows similar behaviour to NOAA and other data sets, but the difficulty is that if data collection and adjustment are informed by the very same theoretical assumptions, and the same assumptions about data collection “problems,” then you can expect the same corrections. They are pursuing their own tails.

  3. The PETM (Paleocene–Eocene Thermal Maximum) was a much more dramatic event. In a world already much warmer than now a very rapid rise of 4-5’C occurred in a geologically short period along with a large increase in CO2. Nothing nasty happened, in fact the reverse life flourished and the seas were filled with fish. When there was a cooling at the end of the Eocene there was a mass extinction.

    According to Wikipedia.

    The Paleocene–Eocene Thermal Maximum (PETM), alternatively “Eocene thermal maximum 1” (ETM1), and formerly known as the “Initial Eocene” or “Late Paleocene Thermal Maximum” was a time period with more than 8 °C warmer global average temperature than today. This climate event began at the time boundary between the Paleocene and Eocene geological epochs.[1] The exact age and duration of the event is uncertain but it is estimated to have occurred around 55.5 million years ago.[2]

    The associated period of massive carbon injection into the atmosphere has been estimated to have lasted no longer than 20,000 years. The entire warm period lasted for about 200,000 years. Global temperatures increased by 5–8 °C.[3] The carbon dioxide was likely released in two pulses, the first lasting less than 2,000 years. Such a repeated carbon release is in line with current global warming.[2] A main difference is that during the Paleocene–Eocene Thermal Maximum, the planet was essentially ice-free.

    CO2 gets the blame but there were changes in ocean circulation which may have caused the initial warming and subsequent CO2 release..

    1. CO2 gets the blame because it is one of the few gases that we cannot live without producing. Coal can burn very clean and it’s by products can be very useful, but you can’t sequester the CO2. Everything we do creates CO2 down to the point of existing. Even Solar is a mass producer of CO2 when you consider the production, installation and disposal of the panels. According to the IPCC you cannot Breath, Eat or take a Dump without contributing to Climate Change and they want to control all of it.

  4. very good point made;-)
    and the bit about continents
    Gondwana which split up- bits of which is Aus i gather were at what we now call antarctica but it wasnt iced over til far later.
    or we were down there but again not cold and bits split and we moved to nearer equator . fuzzy on what happened when

    1. I read a flat earthier and instant creationist.
      It should have read on the seventh day the Progenitor frolicked on the beach with 72 hand maidens, with the population explosion starting soon after.
      When in Rome do as the Roman’s do.

  5. Experts also agree that during this period some of the largest and loudest farts were fiercely emitted from these huge meat eating monsters roaming the globe, adding immensely to the malodorous methane and CO2 load in the atmosphere.

  6. yeaugh about that time the Earth averaged about 78F for the most part – much hotter than today. I’m sure when the Tyrannosaurus rex had sex with another female, they spit out far more CO2 in heavy breathing than 40 humans combined. Yet they didn’t complain about the heat LOL.

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