Climate Change Thread

[Philippus Flavius Homovallumus]

Right idea, but wrong reason. I have a suspicion that our "clean air" is really still considerably toxic relative to pre-industrial levels. When we electrify our transportation and various industries go green/carbon neutral, our baseline levels of illness across the board will show a noticeable drop.

You know, we used to think there was a "natural background level" of lead in the air - there isn't.

If you need to be worried about "Climate Change" to want to clean up the planet then you are the one with the wrong reason.

Even if we had not managed to turn up the heating we would still be living in toxic sludge and everybody needs to see that as a problem in itself.

[Genava]

There was always a good prima facia case for anthropomorphic climate change. The earlier efforts to computer model to "prove" it were chancy, since the models themselves could not replicate known results when preceding data were fed in. The modeling has gotten better. Moreover, ice cores and tree rings and the like are providing a better "fossil" picture of the temperature shift. I have yet to see an absolute proof of causation, but the correlation is so strong as to make it hard to believe that human agency isn't at least partially responsible. Facts are stubborn things.

To defend your point and to give more informations.

Analysis: How well have climate models projected global warming?
https://www.carbonbrief.org/analysis...global-warming

Analysis: Why scientists think 100% of global warming is due to humans
https://www.carbonbrief.org/analysis...-due-to-humans

About causation, there are direct observation of the enhanced greenhouse effect from CO2:
https://phys.org/news/2015-02-carbon...se-effect.html

Observational determination of surface radiative forcing by CO2 from 2000 to 2010
https://www.nature.com/articles/nature14240

Here an excerpt:

Here we present observationally based evidence of clear-sky CO2 surface radiative forcing that is directly attributable to the increase, between 2000 and 2010, of 22 parts per million atmospheric CO2. The time series of this forcing at the two locations—the Southern Great Plains and the North Slope of Alaska—are derived from Atmospheric Emitted Radiance Interferometer spectra together with ancillary measurements and thoroughly corroborated radiative transfer calculations. The time series both show statistically significant trends of 0.2 W m−2 per decade (with respective uncertainties of ±0.06 W m−2 per decade and ±0.07 W m−2 per decade) and have seasonal ranges of 0.1–0.2 W m−2. This is approximately ten per cent of the trend in downwelling longwave radiation. These results confirm theoretical predictions of the atmospheric greenhouse effect due to anthropogenic emissions, and provide empirical evidence of how rising CO2 levels, mediated by temporal variations due to photosynthesis and respiration, are affecting the surface energy balance.

The measured spectrum in Fig. 1a shows Planck function behaviour near the centre of the fundamental (ν2) CO2 band and exhibits a departure from a Planck curve in the P- and R-branches of this feature, indicating that the emission in these branches is sub-saturated and could increase with increasing CO2. Water-vapour features, continuum emission, and O3 emission are seen in the infrared window between 800 cm−1 and 1,200 cm−1, and lesser features from CH4 are seen around 1,300 cm−1. Calculated transmission and the change in transmission with a 22 ppm CO2 increase are also shown, indicating that weak vibration-rotation features in the far wings of the fundamental and in the infrared window dominate surface radiative forcing from rising CO2.

We can exclude alternative explanations for the change in these measurements, such as instrument calibration or the temperature, water vapour, or condensate structure of the atmosphere because they would produce significant (P < 0.003) trends in other spectral regions outside the CO2 absorption bands—see Fig. 2b and e. Moreover, the spectral forcing from CO2 is a strong function of changes in the CO2 column concentration, and nonlinear interactions between temperature and water vapour were weak, as indicated by the lack of statistically significant differences in the seasonal and annual spectral trends in the CO2 P- and R-branches. Therefore, the atmospheric structure of temperature and water vapour does not strongly affect CO2 surface forcing, which is consistent with the findings of others.

About the origins of the consensus here an article from 1956 by Gilbert Norman Plass, a physicist.
https://www.americanscientist.org/ar...nd-the-climate

Here an excerpt:

The fact that water vapor absorbs to some extent in the same spectral interval as carbon dioxide is the basis for the usual objection to the carbon dioxide theory. According to this argument the water vapor absorption is so large that there would be virtually no change in the outgoing radiation if the carbon dioxide concentration should change. However, this conclusion was based on early, very approximate treatments of the very complex problem of the calculation of the infrared flux in the atmosphere. Recent and more accurate calculations that take into account the detailed structure of the spectra of these two gases show that they are relatively independent of one another in their influence on the infrared absorption. There are two main reasons for this result: (1) there is no correlation between the frequencies of the spectral lines for carbon dioxide and water vapor and so the lines do not often overlap because of nearly coincident positions for the spectral lines; (2) the fractional concentration of water vapor falls off very rapidly with height whereas carbon dioxide is nearly uniformly distributed. Because of this last fact, even if the water vapor absorption were larger than that of carbon dioxide in a certain spectral interval at the surface of the Earth, at only a short distance above the ground the carbon dioxide absorption would be considerably larger than that of the water vapor. Careful estimates show that the temperature changes given above for carbon dioxide would not be reduced by more than 20 per cent because of water vapor absorption.

One further objection has been raised to the carbon dioxide theory: the atmosphere is completely opaque at the center of the carbon dioxide band and therefore there is no change in the absorption as the carbon dioxide amount varies. This is entirely true for a spectral interval about one micron wide on either side of the center of the carbon dioxide band. However, the argument neglects the hundreds of spectral lines from carbon dioxide that are outside this interval of complete absorption. The change in absorption for a given variation in carbon dioxide amount is greatest for a spectral interval that is only partially opaque; the temperature variation at the surface of the Earth is determined by the change in absorption of such intervals.

The physical basis for the consensus is explained by the American Chemical Society here:
https://www.acs.org/content/acs/en/c...g-started.html

And the support for the consensus is nicely described here by The Geological Society of America:
https://www.geosociety.org/gsa/posit...osition10.aspx

Taken from here:
https://climate.nasa.gov/scientific-consensus/

Cheers,

Genava