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| heartbroken that John Clauser seems to have joined climate change denial. |
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| cbutlera:
--- Quote from: snarkysparky on August 01, 2023, 02:18:44 am ---I don't understand. This man is an intellectual giant in the science community. He has aligned himself with the very unscientific group "co2coalition" Co2 coalition has no credible challenge to anthropomorphic global warming. why would a man with that history of achievement take such a position unless he really believed it to be the truth. I realize this could be a very short thread before it is locked. I ask every participant to just review the facts which are accepted in the scientific community and not go to conspiracy sources. --- End quote --- On the contrary I think that sceptical sources, relative to your own views, are exactly where you should be going, at least sometimes. What better way to test and hone your own understanding? Far better than relying on the judgement of others, even if they are Nobel laureates. For example, if you know some maths and physics, then this page on the co2coalition website is quite enlightening. It summarises a paper by Van Wijngaarden and Happer and includes the comment “Doubling the CO2 concentration increases the infrared absorption by only a few percent. The reason is that extensive saturation takes place”. This isn’t saturation, it’s a logarithmic response, those few percent make all the difference. On page 26 of the full paper linked to on the above page it states that “Doubling the standard concentration of CO2 (from 400 to 800 ppm) would only cause a forcing increase of ∆F {i} = 3.0 W/m2”. Only? … Compare that figure with the figure of 2.16 (1.9 to 2.41) W/m2 for the approximately 50% increase in atmospheric CO2 concentration between 1750 and 2019 that is given on this IPCC page. 2.16 W/m2 for a 50% increase is equivalent to 2.16 * log(2) / log(1.5) = 3.69 W/m2 for a doubling, so there is no substantial disagreement with the IPCC on the level of forcing. In section 6 starting on page 43 of the W & H paper there is a short, mostly hand-waving type estimate of the climate sensitivity, which comes up with a figure of 1.3K for a doubling of the CO2 concentration. This is significantly lower than the IPCC estimate for equilibrium climate sensitivity of 3C (likely 2.5C to 4C, very likely 2C to 5C). However, there are obvious weaknesses in their argument in this section. They are explicitly doubling the concentration of CO2, but with no change in other greenhouse gas concentrations, which includes water vapour, a very significant amplifier for the sensitivity. There is also no indication that they accounted for the rise in the relevant emission heights that this doubling will cause. (They do briefly mention emission heights in the section of the paper where they calculate the forcing.) On the other hand, in this later and similar paper by the same authors, in section 7 starting on page 21, they make a more detailed estimate of the sensitivity that does include changes in absolute humidity and emission heights. Here they calculate a sensitivity of 2.3K as shown in the table on page 32, which also mentions a 1.4K figure for the unrealistic case of fixed absolute humidity. This value of 2.3K is reasonably consistent with the IPCC value. So does this paper demonstrate the claimed extensive saturation? It doesn't look like it to me, but don't take my word for it, I'm just a nobody on the web with a rusty 40+ year old physics degree and too much spare time on his hands. Read the papers and judge for yourself. Co2 coalition just looks like an advocacy group to me. What they say seems to be technically true, but heavily spun in a way to suit their own agenda, as is typical for such groups. It may catch out the unwary, but life is like that, we live in an ocean of propaganda. I guess that your intellectual giant isn't above bending the truth a little when it suits him, just like the rest of us. Apologies to all for replying to a message so far back in this discussion, but I’m a slow thinker, and it took me a while to digest the papers. Fixed W m2 to W/m2. Ooops. |
| khs:
A simple VERY rough estimation: Doubling CO2 increases effective power to 3 W/m² Solar constant is about 1000 W/m² So we get (1000 W/m² + 3 W/m²) / 1000 W / m²=1.003 We have about 273K+20K = 293K So with 1.003 we get about 294K So the temperature increases about 1K - if I'm not wrong. |
| tautech:
And then we have natural events that each impacted on the earths climate by way of ash and/or water ejection into the stratosphere.....are these included in climatic modeling ? If not, why not ? https://www.aeronomie.be/en/news/2021/30-years-after-mt-pinatubo-eruption-illustration-relationship-between-volcanoes-and https://www.jpl.nasa.gov/news/tonga-eruption-blasted-unprecedented-amount-of-water-into-stratosphere |
| cbutlera:
--- Quote from: khs on August 06, 2023, 10:24:31 pm ---A simple VERY rough estimation: Doubling CO2 increases effective power to 3 W/m² Solar constant is about 1000 W/m² So we get (1000 W/m² + 3 W/m²) / 1000 W / m²=1.003 We have about 273K+20K = 293K So with 1.003 we get about 294K So the temperature increases about 1K - if I'm not wrong. --- End quote --- An equilibrium climate sensitivity of 2.3K isn’t my estimate, it’s from page 32 of Dependence of Earth's Thermal Radiation on Five Most Abundant Greenhouse Gases by Van Wijngaarden and Happer, two scientists whose papers are frequently cited on AGW sceptical websites. They could be wrong. 1000 W/m2 is more like the peak solar power when the sun is directly overhead. The earth intercepts a disc of solar radiation of area pi * R2, where R is the radius of the earth. The surface area of the earth is 4 * pi * R2, so the average solar power is more like 1/4 of the peak power. |
| cbutlera:
--- Quote from: tautech on August 06, 2023, 10:38:14 pm ---And then we have natural events that each impacted on the earths climate by way of ash and/or water ejection into the stratosphere.....are these included in climatic modeling ? If not, why not ? https://www.aeronomie.be/en/news/2021/30-years-after-mt-pinatubo-eruption-illustration-relationship-between-volcanoes-and https://www.jpl.nasa.gov/news/tonga-eruption-blasted-unprecedented-amount-of-water-into-stratosphere --- End quote --- If the scientists on the AGW sceptical side of the argument believe that to be the case, then they should create and publish their own models that do include such effects, or adapt an existing published model. What could be a more powerful counterargument to say the NASA GISS general circulation models than an alternative, scientifically plausible GCM, that fits the last few decades climate records just as accurately but does not require an increasing level of CO2 to do so? As far as I am aware no such alternative GCMs exist and one has to ask why? |
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