Jovial Monk wrote on Apr 10^th, 2021 at 6:55pm:



poor petal. 

"The new research, published in the journal Geophysical Research Letters, uses the latest generation of climate models from 21 research institutes from around the world. In climate studies, the Arctic Ocean is said to be ice-free when it shrinks to fragments with a combined area below 1m sq km, which is 75% lower than in 2019."

https://www.theguardian.com/world/2020/apr/21/ice-free-arctic-summers-now-very-l...

You do believe the garudian; don't you?

Or perhaps this -

"Still, most CMIP6 models fail to simulate at the same time a plausible evolution of sea‐ice area and of global mean surface temperature. In the vast majority of the available CMIP6 simulations, the Arctic Ocean becomes practically sea‐ice free (sea‐ice area <1 × 10⁶ km2) in September for the first time before the Year 2050 in each of the four emission scenarios SSP1‐1.9, SSP1‐2.6, SSP2‐4.5, and SSP5‐8.5 examined here."

https://agupubs.onlinelibrary.wiley.com/journal/19448007

Jovial Monk wrote on Apr 10^th, 2021 at 6:55pm:



You really, really need to keep up petal.

Jovial Monk wrote on Apr 10^th, 2021 at 7:31pm:



Poor petal. trying so hard to be woke.

Jovial Monk wrote on Apr 10^th, 2021 at 7:41pm:



Poor petal. Trying to prove something?

Jovial Monk wrote on Apr 10^th, 2021 at 7:41pm:


Yes you are a coward. And more than a bit.

Jovial Monk wrote on Apr 11^th, 2021 at 11:34am:



You mean CO2 is not the control knob via feedbacks? Heresy.

But you do know that they are not mutually exclusive?

Differing feedbacks, differing time frames. The ocean with its ability to store heat energy has a long feedback time. Air does not. So these differing feedbacks have a different frequency and depending on the start conditions may be in or out of phase to differing degrees at any one time. And that is one of the failures of climate models. The start condition.

Feedback Catastrophes? (1960s) 
Norbert Wiener, a mathematical prodigy, had interests ranging from electronic computers to the organization of animals' nervous systems. It was while working on automatic control systems for antiaircraft guns during the Second World War that he had his most famous insights. The result was a theory, and a popular book published in 1948, on something he called "cybernetics."(55) Wiener's book drew attention to feedbacks and the stability or collapse of systems. These were timely topics in an era when electronics opened possibilities ranging from automated factories to novel modes of social communication and control. Through the 1950s, the educated public got used to thinking in cybernetic terms. Climate scientists were swimming with the tide when they directed their attention to feedback mechanisms, whereby a small and gradual change might trigger a big and sudden transition.      

At the start of the 1960s, a few scientists began to think about transitions between different states of the oceans. Study of cores drilled from the seabed showed that water temperatures could shift more quickly than expected. A rudimentary model of ocean circulation constructed by Henry Stommel suggested that under some conditions only a small perturbation might shift the entire pattern of deep currents from one state to another. It was reminiscent of the shifts in the dishpan fluid models.(56) All this was reinforced by the now familiar concept that fluctuations in ice sheets and snow cover might set off a rapid change in the Earth's surface conditions.(57)      

Similar ideas had been alive in the Soviet Union since the 1950s, connected to fabulous speculations about deliberate climate modification — making Siberia bloom by damming the Bering Straits, or by spreading soot across the Arctic snows to absorb sunlight. According to the usual ideas invoking snow albedo, if you just gave a push at the right point, feedback would do the rest. These speculations led the Leningrad climatologist Mikhail Budyko to privately advance worries about how feedbacks might amplify human influences. His entry-point was a study on a global scale. Computing the balance of incoming and outgoing radiation energy according to latitude, Budyko found the heat balance worked very differently in the snowy high latitudes as compared with more temperate zones. It took him some time, Budyko later recalled, to understand the importance of this simple calculation.(58) It led him to wonder, before almost any other scientist, about the potentially huge consequences of fossil fuel burning as well as more deliberate human interventions.      
<=>Climate mod

In 1961, Budyko published a generalized warning that the exponential growth of humanity's use of energy will inevitably heat the planet. The next year he followed up with more specific, if still quite simple, calculations of the Earth's energy budget . His equations suggested that climate changes could be extreme. In the nearer term, he advised that the Arctic icepack might disappear quickly if something temporarily perturbed the heat balance. Budyko did not see an ice-free Arctic as a problem so much as a grand opportunity for the Soviet Union, allowing it to become a maritime power (although he admitted the longer-term consequences might be less beneficial).(59)      

Even setting aside ice-albedo effects, interest in feedbacks was growing. Improvements in digital computers were the main driving force. Now it was possible to compute feedback interactions of radiation and temperature along the lines Arrhenius had attempted, but without spending months grinding away at the arithmetic. A few scientists took a new look at the old ideas about the greenhouse effect. Nobody fully grasped that the arguments about "saturation" of absorption of radiation were irrelevant, since adding more gas would make a difference in the crucial high, thin layers from which much of the radiation does escape into space. But the way radiation traversed the layers was attracting increasing scientific attention. As spectroscopic data and theoretical understanding improved, a few physicists decided that it was worth their time to calculate what happened to the radiation in detail, layer by layer up through the atmosphere. (The details are discussed in the essay on Basic Radiation Calculations, follow link at right.)      

In 1963, building on pioneering work by Gilbert Plass, Fritz Möller produced a model for what happens in a column of typical air (that is, a "one-dimensional global-average" model). His key assumption was that the water vapor content of the atmosphere should increase with increasing temperature. To put this into the calculations he held the relative humidity constant, which was just what Arrhenius had done long ago.(60) As the temperature rose more water vapor would remain in the air, adding its share to the greenhouse effect.      

. . .Möller was astounded by the result. Under some reasonable assumptions, doubling the CO2 could bring a temperature rise of 10°C — or perhaps even higher, for the mathematics would allow an arbitrarily high rise. More and more water would evaporate from the oceans until the atmosphere filled with steam! Möller himself found this result so implausible that he doubted the whole theory. et others thought his calculation was worth noticing. The model, as one expert noted, "served to increase confusion as to the real effect of varying the CO2 concentration.

Look up “equilibrium” lee.

Quote:

[quote]      

The CO2 Greenhouse Effect Demonstrated (1950-1967)

Digital computers were indeed being pressed into service. Some groups were exploring ways to use them to compute the entire three-dimensional general circulation of the atmosphere. But one-dimensional radiation models would be the foundation on which any grander model must be constructed — a three-dimensional atmosphere was just an assembly of a great many one-dimensional vertical columns, exchanging air with one another. It would be a long time before computers could handle the millions of calculations that such a huge model required. So people continued to work on improving the simpler models, now using more extensive electronic computations.      

Most experts stuck by the old objection to the greenhouse theory of climate change — in the parts of the spectrum where infrared absorption took place, the CO2 plus the water vapor that were already in the atmosphere sufficed to block all the radiation that could be blocked. In this "saturated" condition, raising the level of the gas could not change anything. But this argument was falling into doubt. The discovery of quantum mechanics in the 1920s had opened the way to an accurate theory for the details of how absorption took place, developed by Walter Elsasser during the Second World War. Precise laboratory studies during the war and after confirmed a new outlook. In the frigid and rarified upper atmosphere where the crucial infrared absorption takes place, the nature of the absorption is different from what scientists had assumed from the old sea-level measurements.
     
Take a single molecule of CO2 or H2O. It will absorb light only in a set of specific wavelengths, which show up as thin dark lines in a spectrum. In a gas at sea-level temperature and pressure, the countless molecules colliding with one another at different velocities each absorb at slightly different wavelengths, so the lines are broadened considerably. With the primitive infrared instruments available earlier in the 20th century, scientists saw the absorption smeared out into wide bands. And they had no theory to suggest anything else.
     
A modern spectrograph shows a set of peaks and valleys superimposed on each band, even at sea-level pressure. In cold air at low pressure, each band resolves into a cluster of sharply defined lines, like a picket fence. There are gaps between the H2O lines where radiation can get through unless blocked by CO2 lines. That showed up clearly in data compiled for the U.S. Air Force, drawing the attention of researchers to the details of the absorption, especially at high altitudes. Moreover, researchers working for the Air Force had become acutely aware of how very dry the air gets at upper altitudes—indeed the stratosphere has scarcely any water vapor at all. By contrast, CO2 is fairly well mixed all through the atmosphere, so as you look higher it becomes relatively more significant.(9a)
     
The main points could have been understood in the 1930s if scientists had looked at the greenhouse effect carefully (or if they had noticed Hulburt's paper, which did take a careful look, or had pursued still earlier remarks by Arrhenius himself). But it was in the 1950s, with the new measurements in hand, that a few theoretical physicists realized the question was worth a long and careful new look. Most earlier scientists who looked at the greenhouse effect had treated the atmosphere as a slab, and only tried to measure and calculate radiation in terms of the total content of gas and moisture. But if you were prepared to tackle the full radiative transfer calculations, layer by layer, you would begin to see things differently. What if water vapor did entirely block any radiation that could have been absorbed by adding CO2 in the lower layers of the atmosphere? It was still possible for CO2 to make a difference in the thin, cold upper layers. Lewis D. Kaplan ground through some extensive numerical computations. In 1952, he showed that in the upper atmosphere the saturation of CO2 lines should be weak. Thus adding more of the gas would certainly change the overall balance and temperature structure of the atmosphere.(10)      

Neither Kaplan nor anyone else at that time was thinking clearly enough about the greenhouse effect to point out that it will operate regardless of the details of the absorption. The trick, again, was to follow how the radiation passed up layer by layer. Consider a layer of the atmosphere so high and thin that heat radiation from lower down would slip through. Add more gas, and the layer would absorb some of the rays. Therefore the place from which heat energy finally left the Earth would shift to a higher layer. That would be a colder layer, unable to radiate heat so efficiently. The imbalance would cause all the lower levels to get warmer, until the high levels became hot enough to radiate as much energy back out as the planet received. (For additional explanation of the "greenhouse effect," follow the link at right to the essay on Simple Models.) Adding carbon dioxide will make for a stronger greenhouse effect regardless of saturation in the lower atmosphere.      

Nearly at the stage of the first real radiative-convective numerical model of Manabe and Wetherald.