I will have to print and read this later but this open paper looks interesting: https://www.nature.com/articles/ncomms14845 Understand I prefer current data from the satellite era in part because it leads to improvements in the climate models. What attracts me to this article is the first paragraph: The primary source of energy in the Earth’s climate system is incoming solar radiation, termed total solar irradiance, or TSI. At equilibrium, because of the requirement of energy conservation, the Earth’s radiative budget must balance such that TSI is equal to outgoing longwave radiation at the top of the atmosphere (a state known as radiative equilibrium). Since the radiation emitted by a body is a function of surface temperature, the Earth’s ‘effective temperature’ (TE) is the temperature at which radiative equilibrium is achieved assuming the Earth acts like a blackbody, and can be calculated (in K) using the following expression: TE = (Fs(1-A) / 4s] ** 0.25 = 256 K where Fs is the TSI (currently B1,368Wm2), s is the Stefan– Boltzmann constant (5.67108Wm2K4), A.0.29 (ref. 1) is the Earth’s average planetary albedo (the fraction of incoming radiation scattered or reflected back out of the atmosphere by clouds, particulates in the atmosphere and the Earth’s surface), and the factor of 4 accounts for the spherical and rotating nature of the Earth. The 31 K difference between TE and the observed surface temperature of the Earth (.14.0 C or 287.1K is the 1961–1990 mean2) is almost entirely due to the action of the greenhouse effect (for example, ref. 3). This matches the path to enlightenment of climate scientists when they realize the magnitude of man-made, global warming on the earth. Sure there was nearly 100 years of papers on greenhouse gas effects. But the physics in this paper pretty well lays down the bar and supports the most recent efforts to mitigate man-made, CO{2} heating of our planet. I am still reading the paper but there is enough information that we can test the claimed 'sun spot' effects on the future earth temperature. Testing without requiring acceptance of the 'Sun Spot' papers predicting a cooling trend approaching. Bob Wilson
In contrast I am totally a fan of paleoproxies because how else can you understand how biological evolution has modified the earth? I consider fossils to be proxies for (extinct) biological organisms - you may not, but as such it is hard not to be a fan of them. Foster et al. Fig. 1 is as nice a CO2 record as we yet have. The smoothed red curve is irritating to me, but by Fig. 2 their motive is clear. Imagine, beyond all the other amazing coincidences abut earth, that CO2 forcing decrease nicely balances solar forcing increase over 400 million years! So very helpful for climatic homeostasis! I don't understand why the sun 'heats up' in this linear way, but solar physicists say so. Whadagonnado? Maybe most stars do this. As such, candidate biological planets all face challenges. They may be in 'habitable zones' when life pops up, but over time the habitable zone gets further out. What are they gonna do? If lucky, arrange for CO2 decrease through time. Maybe there are other ways to achieve climatic homeostasis. Earth did it by sequestering LOTS of CO2 in limestone and LESS in fossil carbon. Nobody wants to put limestone CO2 back in the atmosphere - ain't no money in it That other thing - well yeah. +++ Limestone does get subducted and decomposed and re-released as (oceanic) crust turns over. This approximately 200-million-year thing is called The Wilson Cycle. Ta-da! No connection to our thread starter here. Nor to volleyball with red handprint AFAIK
It has to do with 'ground truth', checking the satellite data against the earth surface. It isn't that paleo records are useless but there is: The Kentucky Creationist Museum that treats the Flintstones as a documentary. Yes, another happy 'accident' but sometimes it happens. Move but there in lies another problem. When the star burns up its nuclear fuel(s), passing through a red giant, and assuming it doesn't nova (our Sun is too small,) it shrinks to a white dwarf. Only the inner planets would have been consumed leaving no habitable planetary masses. The outer ones too cold. Hummm, is there enough calcium to absorb the fossil CO{2}? Bob Wilson
Enough calcium? Yes, in that limestone is CaCO3. But things happen at different rates. We do, in fact, break limestone to make concrete. Lots of it. That second rock slowly reabsorbs half of original CO2. White dwarf. In the case of 'El Sol' an important step is missing above. Becomes Red Giant (possible as large as Earth's orbit, with serious consequences). Then a few more burps before White Dwarf. This is what solar physicists say. I would not comment. I understand there are places where dinosaur and hominid fossils can be found in close proximity. This is very pro-Flintstone. However things get jumbled up in geology sometimes. Need to unwind with radioactive isotope dating. This is one reason why Young Earth adherents need isotope dating to be wrong. A lot of effort is expended in that way.
Related, for those interested in climate-model testing: https://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3278.html Currently 'netting from a private line so I see the paywall just as you do. Nature does not even show Armour's email. Fixed that for ya Kyle Armour | University of Washington
How much calcium is available in basalts, for additional CO2 absorption? A recent test (in Iceland?) found surprisingly fast update, much quicker than geologic time. And should additional testing continue to produce positive results, we have a ginormous deposit near here forming the Columbia Basin Plateau. The inherent lower energy harvest associated with carbon capture, however, will leave many fossil fuels with a cost disadvantage.
At some point, we need to be able to move completely out of this solar system, to others that are either young, or have longer-lived (though smaller) suns.
Concerning the Armour article, we are still left with a range of climate sensitivities (+T associated with CO2 doubling). It seems to have been this way for a long time. I can't imagine that better paleo proxies would settle that. Better climate modeling could (might), but I frankly have no idea if those folks feel motivated to 'do oceans' better. Or if data exist to aid them, even with interest. With all that in mind, it is interesting that Armour suggests that additional look-down satellites could make large contribution: Will Earth’s Climate Get More Sensitive to CO2? Only Better Satellites Can Say - IEEE Spectrum Notice that such $atellite $pending may or may not happen in Washington's 'climate'. So there it sits, ladies and gents. The persistent range of uncertainty is (for some at least) a strong argument against disruptive anti-fossil-C action. Government may not want to pay to make that uncertainty smaller. +++ If BobW 'likes' this, it will be because of link to IEEE - not for any fabulous insights posted here.
Out of an abundance of caution, I would hold off on speculations that CO{2} effects might be amplified by a higher mean. There are so many interactions with secondary effects, it would have to be geological carbon releases and then we're condemned to a Venus h*ll. Bob Wilson
Greetings new member places to visit. I have a feeling that there must be stories about having a 2005 Prius in Hanoi...
