20 thoughts on “Climate “Tipping Points””

  1. Given “chaos mathematics”, I would suppose any — should one exist at all — tipping point could tip the weather/climate into a dozen centuries of ice age just as easily as “tip” into continuing the recent few decades of warming.

  2. Somewhere in this long discussion between Jordan Peterson and Richard Lindzen (Youtube video), Lindzen makes the point that the more degrees of freedom a system has, the less likely it is to have a tipping point. If there is some particular forcing pushing on the system, there are more ways the system can relieve the force without letting it build until there’s an abrupt discontinuity.

    Part of the alarmist world-view is that the climate is a very fragile system, full of positive feedbacks. 500 million years of data says it’s a very robust system, full of negative feedbacks, when not smacked by giant asteroids.

    1. There are several steady states from the geological record among several states of ice coverage: complete coverage (snowball Earth), the large glacial coverage (like during the last glacial period), present day, and ice-free. It’s likely that some sort of tipping point exists between each pair of states, else they wouldn’t be distinct states. But what parameters are needed, and how long it takes to tip are unknown. It doesn’t sound like we’re close to one at present.

      1. The Snowball Earth Theory is fascinating. You’re right that something triggered the conditions to freeze the Earth’s surface at least twice, but scientists don’t know what the triggering events were. The Earth looked very different back then. There were some massive volcanic activity and the supercontinent Rodinia was beginning to break apart. These things are discussed in the linked article below.

        https://astronomy.com/news/2019/04/the-story-of-snowball-earth

        1. The ocean floor is young surface and it’s 70% of the surface of the planet.
          There are ice caps in our tropics, now, and it seems plausible there at some point was ice sheets in tropics, but wouldn’t mean Earth was in snowball climate.
          We have been in the Late Cenozoic Ice Age for 33.9 million years and it’s thought to one of five known Ice Ages, Earth has had.
          In addition to possibility of having much higher elevation in tropics and thereby allowing ice sheet, it seems we have short period events caused volcanic or impacts, like the time “there was no summer”, which could cool the atmosphere, by a lot.
          But global climate is largely about the ocean- it holds 1000 times more heat then our sky. And average temperature of our ocean is about 3.5 C and this cold ocean is reason we are now in the coldest times of this 33.9 million year icehouse global climate.

          1. Wodun, if the deep core is somehow transferring small amounts of energy to the oceans, that would cause some degree of cooling of the core region over geological times. No idea if it’s happening, but it’s not something that geologists have noticed. Which would be some sort of bound on how much energy could be transferred over billions of years.

          2. I don’t recall if the author mentioned the core cooling but did talk about the rotation of Earth slowing from the exchange and speculated that it is related to the poles moving.

            The bit about where heat waves come from was something I hadn’t heard suggested before.

  3. A very cute hypothesis about the control of deglaciation appears in:

    Ellis, R. and Palmer, M., 2016. Modulation of ice ages via precession and dust-albedo feedbacks. Geoscience Frontiers, 7(6), pp.891-909.

    The onset of glaciation is controlled by orbital mechanics and the precession of the Earth’s rotation axis. Every time things synchronize for a glaciation, we get continental ice sheets. The mystery has been that we tend to go through 4 or 5 deglaciation “triggers” before warming up. Why the asymmetry? This paper postulates that the high albedo of the ice sheets prevents them from melting during the brief warming periods. It’s only after the Earth has cooled so much that CO2 levels drop to dangerously low levels and plants and even C4 grasslands die off, that a warming period can get started. At these points, great dust storms (think loess deposits) start coating the ice sheets. At such times, when the N. Hemisphere summers get long enough, the ice finally melts and we can get one and only one warm period. So CO2 does control deglaciation, not via temperature feedback but by CO2 starvation after protracted periods of glaciation. There’s a certain splendor to this theory.

    1. “The onset of glaciation is controlled by orbital mechanics and the precession of the Earth’s rotation axis. Every time things synchronize for a glaciation, we get continental ice sheets.”

      I would say the onset of interglacial period is controlled by orbital mechanics and the precession of the Earth’s rotation axis.
      Which what most people say.
      But I would say, ocean warms and land cools.
      Which hardly anyone says. And I would further in land of what no one says, and say ice sheet don’t cause the land to cool more and don’t even cause much global cooling, but having polar sea ice, inhibit a liquid ocean to warm the land. So it’s polar sea ice which cause the lower global air surface temperature.
      But it’s average temperature of the entire ocean which controls global temperature [and global air surface temperature].
      NASA and NAAO sort of agree with me, when they say,
      more than 90% of global warming is warming our cold ocean with average temperature of about 3.5 C.
      If the entire ocean warmed to 4 C, one get about 1 foot of global sea level from the thermal expansion.
      Past warmer interglacial period had ocean of about 4 C
      or warmer and had 4 to 9 meter of sea level rise.
      Our earlier part of Holocene and about 1 to 2 meter higher sea level than present sea level. And as I said, other had 4 to 9 meter.
      One could say our Holocene was an odd interglacial period- and there are many theories of why. But there is agreement it has been cooler than past periods which called interglacial periods.
      But back to my crazy ideas, I think polar sea ice warms the whole ocean. And the “orbital mechanics and the precession of the Earth’s rotation axis” melts polar ice- which can melted pretty fast- as 5 meter thick sea ice can currently be melted in summer season. And sea ice which being melted is much further away from polar region. And when significant amount sea ice melted and well past say the UK, the ocean/Gulf stream can warm up Europe by 10 C [or right now the gulf stream warms Europe by about 10 C, and the ocean wouldn’t 3.5 C, but has been warmed up to 4 C or warmer].

      Or if instead of being 3.5 C, the ocean was 4 C, our global average temperature would be about 17 to 18 C
      rather than about 15 C.

      1. Or if ocean was 4 C, we would certainly have ice free polar sea ice in the Arctic- which many say would be a big problem and could lead to ice free in the winter, which is said to be a bigger problem.
        With ocean of 5 C, you don’t polar ice sea in either pole in winter.
        But if ocean warmth dumping heat in the polar region, it will cool the entire ocean.

      2. Sorry, but full blown glacial conditions begin when there’s a rise in continental glaciation. This is a powerful positive feedback system when you get kms of ice sitting on land as far south as about 45N. Polar sea ice has little albedo effect because it exists “where the sun don’t shine”, at least very much. In the grand scheme of things, we are in a comparative ice age today, as we do have continental glaciation (Antarctica and Greenland). For the past few Myr, when the precession wheel rolls around and we get short N Hemisphere summers, we ALWAYS go into a full blown glacial, as snow in N Quebec and N Manitoba and Fennoscandia does not have time to melt in the summer. This mechanism is pretty well understood, but the mystery has always been why you usually DON’T get an interglacial when you get long N. Hemisphere summers. You have to go through 4 or 5 of them before the non-linear climate oscillator kicks over to the warmer bistable state. The Ellis and Palmer hypothesis handles this puzzle quite nicely.

        1. “Throughout Earth’s climate history (Paleoclimate) its climate has fluctuated between two primary states: greenhouse and icehouse Earth. Both climate states last for millions of years and should not be confused with glacial and interglacial periods, which occur as alternate phases within an icehouse period and tend to last less than 1 million years.”
          https://en.wikipedia.org/wiki/Greenhouse_and_icehouse_Earth

        2. Ellis and Palmer paper here.

          As a side note, one sad aspect of the current interglacial is that the dramatic rise in sea level flooded all the coastal areas were humans likely lived during the migration and expansion out of Africa.

  4. “Although the lack of an impending climate cliff may seem to dilute the impetus for climate action, the knowledge that humanity has a decisive hand on the thermostat actually imparts great responsibility upon us.”

    In a long essay about how he was wrong, how does the author not question his other presumptions? Decades of failed predictions have zero impact.

    “It’s up to us not only to realize a more positive future for humans and nature but also to define the conditions in which we will have to build that vision.”

    A positive future is one where the neo-pagans realize the limits of their divinity and attain some level of humility with the admission that they are irrational religious fanatics rather than dispassionate rational atheists, which don’t exist.

  5. Just out of curiosity, have any of the computer climate models on which all the scare-mongering is based ever successfully predicted the past? Put in all the known climate data up to 1980, then “predict” all subsequent years, and compare the predictions to what the historic record says actually happened.

    Last I heard it mentioned, no computer model had passed that test. Generally significantly over-predicting warming.

    1. If they can’t fit the past well, then they aren’t really trying. With enough parameters you can fit any past to any future.

      1. That’s the problem. With enough finesse, you can craft your model to take known starting conditions and generate results for known ending conditions. That doesn’t prove your model is actually modeling the climate. It could just mean that your model is good enough at curve-fitting to fit the known data. It doesn’t prove the model can predict future conditions.

  6. There’s a hypothesis that at high CO2 levels, e.g. ~1200 PPM (currently ~420), that low-cloud cover may sharply drop reducing Earth’s albedo. But that still should not lead to any sort of runaway greenhouse effect. Emissivity still goes up as the temperature to the fourth power and with less cloud coverage, that should reduce the atmosphere’s optical depth, giving photons a shorter path up and out. https://www.carbonbrief.org/extreme-co2-levels-could-trigger-clouds-tipping-point-and-8c-of-global-warming/#:~:text=Very%20high%20levels%20of%20CO2,lower%20levels%20of%20the%20atmosphere.

    “Glacial periods occur when the Earth’s orbit is elongate, when the Earth’s axis has a low tilt, and when northern hemisphere summer occurs at a position on the orbit farther away from the sun so that it is cool.” https://climate.nasa.gov/news/2948/milankovitch-orbital-cycles-and-their-role-in-earths-climate/#:~:text=Earth's%20axis%20is%20currently%20tilted,about%209%2C800%20years%20from%20now.

  7. Rep. Hank Johnson (D-GA) has identified a terrifying tipping point, which would without question be of anthropogenic doing. If the United States stations enough Marines on the island of Guam, he sas a specific fear about the tipping point that may result (starts at 1:14).
    https://www.youtube.com/watch?v=cesSRfXqS1Q

    Our leaders: where do we find such men? And is it too late to return them?

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