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from the but-Al-Gore-told-us-different dept.
The supposed deleted text:
The Sun is the primary forcing of Earth's climate system. Sunlight warms our world. Sunlight drives atmospheric and oceanic circulation patterns. Sunlight powers the process of photosynthesis that plants need to grow. Sunlight causes convection which carries warmth and water vapor up into the sky where clouds form and bring rain. In short, the Sun drives almost every aspect of our world's climate system and makes possible life as we know it.
Earth's orbit around and orientation toward the Sun change over spans of many thousands of years. In turn, these changing "orbital mechanics" force climate to change because they change where and how much sunlight reaches Earth. (Please see for more details.) Thus, changing Earth's exposure to sunlight forces climate to change. According to scientists' models of Earth's orbit and orientation toward the Sun indicate that our world should be just beginning to enter a new period of cooling — perhaps the next ice age.
However, a new force for change has arisen: humans. After the industrial revolution, humans introduced increasing amounts of greenhouse gases into the atmosphere, and changed the surface of the landscape to an extent great enough to influence climate on local and global scales. By driving up carbon dioxide levels in the atmosphere (by about 30 percent), humans have increased its capacity to trap warmth near the surface.
Other important forcings of Earth's climate system include such "variables" as clouds, airborne particulate matter, and surface brightness. Each of these varying features of Earth's environment has the capacity to exceed the warming influence of greenhouse gases and cause our world to cool. For example, increased cloudiness would give more shade to the surface while reflecting more sunlight back to space. Increased airborne particles (or "aerosols") would scatter and reflect more sunlight back to space, thereby cooling the surface. Major volcanic eruptions (such as that of Mt. Pinatubo in 1992) can inject so much aerosol into the atmosphere that, as it spreads around the globe, it reduces sunlight and cause Earth to cool. Likewise, increasing the surface area of highly reflective surface types, such as ice sheets, reflects greater amounts of sunlight back to space and causes Earth to cool.
Scientists are using NASA satellites to monitor all of the aforementioned forcings of Earth's climate system to better understand how they are changing over time, and how any changes in them affect climate.
Supposed screenshot of the page: https://s3.amazonaws.com/jo.nova/debunk/us/nasa/nasa-climate-forcings-2010.gif
Supposed archive.org link (no longer works):
https://web.archive.org/web/20100416015231/https://science.nasa.gov/earth-science/big-questions/what-are-the-primary-causes-of-the-earth-system-variability/]
Articles from 2010-2011 quoting the link and then noting it has disappeared:
https://www.americanthinker.com/blog/2010/12/climate_change_its_the_sun_stu.html
https://www.americanthinker.com/blog/2011/01/nasas_muzzle_hustle.html
Is this fake news? Can anyone here verify whether this page ever existed (or not)?
(Score: 2) by bradley13 on Thursday February 21 2019, @08:02PM (9 children)
I'll take point 3, thanks. CO2 is a tiny proportion of the atmosphere, an a very minor greenhouse gas. All of the catastrophic AGW models rely on cascading effects and/or positive feedback. Typically they hypothesize that a slight warming from CO2 will cause more water to enter the atmosphere, and water has a much more significant effect. But they generally assume that more water does not lead to much more cloud cover.
And that's the point. Most natural systems are dominated by negative feedback. Historical climate data, from times with higher CO2 and higher temperatures indicates that this is true here as well. Likely more water in the atmosphere will lead to more cloud cover, reducing warming rather than increasing it.
Everyone is somebody else's weirdo.
(Score: 4, Informative) by Immerman on Thursday February 21 2019, @11:54PM (8 children)
There are two primary greenhouse gasses: water, and CO2. Everything else is either transparent to infrared and has no greenhouse effect, or is present in quantities 100x smaller than CO2. Water currently averages probably somewhere around 2.5% (20 to 25,000ppm) of the atmosphere. It varies wildly, but is self-regulating in the sense that the warming from increasing the average amount of water in the air by one unit, is not enough to let the air hold a full one additional unit of water. So the percent humidity increases, and with it the chance of precipitation.
CO2 in contrast is now a bit over 400ppm, so around (405/25,405) = 1.6% of the total with water. Doesn't sound like much, right? First lets put it in proper perspective: What would the average temperature of the Earth be if not for greenhouse warming? Well, we can look at the moon - it varies from 106C during the day, to -183C at night - call it an average of -38.5C, as compared to the Earth's average temperature of 14.6C. So greenhouse gasses are currently keeping the planet about 53C warmer than "normal" for this orbit. And probably much more - the Moon is quite dark colored, and absorbs about 31% more solar energy than the Earth (it reflects 12% of sunlight compared to the Earth's 33%)
So, at least 53C of current greenhouse-gas warming that's keeping our planet from being a frozen ball of ice. Even if we assume that CO2 is no more potent a greenhouse gas than water, it's directly responsible for somewhere around 0.85C of heating.
And CO2 has a crucial difference to water - it doesn't increase humidity. In fact, when you increase the amount of CO2 in the air, without changing the amount of water, the resulting warming increases the amount of water that the air can hold, and lowers the % humidity. Which means that in reality more water will evaporate to restore an equilibrium humidity. So by adding more CO2 to the air, you also add more water, just to maintain the same humidity. And of course, more warming from that water.
How strong is that effect? Well, at around 15C the maximum water content of air changes by about 7% per degree C. So, if CO2 causes 0.85C of heating on its own, then the air will have to carry 7% more water to maintain the same humidity So that ~1.6% of the total greenhouse gas of CO2 is actually responsible for the presence of another 6% of the water in the atmosphere, for a combined 7.6% of the total greenhouse warming - or 4C out of my 53C total estimate. And the effect gets more dramatic at higher temperatures - get closer to 20C, and the saturation point is increasing by around 9% per degree C.
(Score: 0) by Anonymous Coward on Friday February 22 2019, @03:38PM (7 children)
Your numbers for the moon are way too high. Avg temp is more like 150 K (-120 C).
>"The mean temperature at the equator (◇) is 215.5 K with an average maximum of 392.3 K and average minimum of 94.3 K (arrows show range between average maximum and minimum Tbol). The mean temperature of the polar regions poleward of 85° (○) is 104 K with an average maximum of 202 K and average minimum of 50 K "
https://www.sciencedirect.com/science/article/pii/S0019103516304869 [sciencedirect.com]
But Im sure that doesnt change your argument, which shows that these calculations you did are just to make it seem more sciency than it actually is.
(Score: 2) by Immerman on Friday February 22 2019, @05:59PM (6 children)
Thank you! I couldn't find an actual average temperature for the moon, which is why I calculated a rough average from the peak temperatures that were all Google offered for "temperature of the moon", I figured using the equator would give me an estimate that would almost certainly be too high - weakening my argument, while still proving my point and making sure my final estimate of the effects of greenhouse gases was above reproach.
Everything else is easily verified data and straight-forward rough back-of-the-napkin calculations, so that any intellectually honest person can see for themselves that the "400ppm is way too tiny to make any difference" argument is baseless.
The reality is obviously more complicated, but such rough calculations give you a "sanity check" idea of roughly how big various effects can reasonably be expected to be. They are quite common in conversations among scientists, and are something that anyone who has a interest in a topic can do for themselves, without having to understand all the underlying science. Occasionally reality departs wildly from such "sanity check" estimates, but that's the exception rather than the rule. It's when a claim disagrees wildly with a "sanity check" that you want to start demanding vigorous evidence. In this case, the sanity check says that the tiny amount of CO2 does in fact make a substantial difference.
If the average temperature of the moon is actually -120C, then that only makes my argument that much stronger: that would mean that greenhouse warming on Earth is currently responsible for at least 14.6 - (-120) = 134.6C in excess warming, and CO2's paltry 1.6% of greenhouse gas emissions reasonably corresponds to 1.6%*134.6C = 2.15C in direct warming effect, which in turn corresponds to increasing the water content in the atmosphere at the same humidity level by about (7%/C)*2.15C = 15%. And the total amount of warming indirectly attributable to that CO2 would be (15%+1.6%)*134.6C = 22C
(Score: 0) by Anonymous Coward on Friday February 22 2019, @07:49PM (5 children)
The moon also has a month long day and no high heat capacity oceans.
(Score: 2) by Immerman on Saturday February 23 2019, @04:07PM (4 children)
True. However, heat capacity is mostly relevant to stabilizing temperatures, keeping them closer to the average - it doesn't alter what the average is. Except insofar as it reduces peak thermal radiation, which is decidedly nonlinear with temperature.
Sadly I think the moon is as good as it gets for actual physical data. We could instead look at purely computational estimates such as the effective temperature - but those model the planet as something only barely more sophisticated than a perfect black body (which will be appreciably warmer)
(Score: 0) by Anonymous Coward on Saturday February 23 2019, @11:00PM (2 children)
>"However, heat capacity is mostly relevant to stabilizing temperatures, keeping them closer to the average - it doesn't alter what the average is."
Sure it does, due to holders inequality: https://en.m.wikipedia.org/wiki/H%C3%B6lder's_inequality [wikipedia.org]
More uniform temperatures will have a higher average temperature for the same amount of energy.
(Score: 2) by Immerman on Sunday February 24 2019, @05:23PM (1 child)
Indeed. So, can you suggest a non-controversial estimate of the equilibrium temperature of an Earth-bright object in our orbit without greenhouse gasses? It is one of those really important data points in the whole conversation, and I've found precious little relevant data.
(Score: 0) by Anonymous Coward on Monday February 25 2019, @03:07PM
No, the climate researchers have only provided "algebra lessons" like the calc to get 255K, and then climate models w thousands of parameters to tune.
(Score: 0) by Anonymous Coward on Saturday February 23 2019, @11:34PM
See section 3 here: http://adsabs.harvard.edu/abs/2013arXiv1303.7079L [harvard.edu]