Slashdot Mirror

Your numbers are wrong. CO2 doubling from pre-industrial level of 280ppm (to 560ppm) is supposed to generate 1.2C. source: https://scienceofdoom.com/2010...
Because the effect is logarithmic, it takes more and more CO2 to barely budge the temperature as CO2 concentrations rise. To generate another 1.2C in temperature rise, we would then have to increase CO2 to 1120ppm. To add a third increase of 1.2C, we need to get the concentration up to 2240ppm. There's not enough oil in the world to get CO2 concentrations up this high.

questions is to what extent the impact of humans may be responsible.

No, this is fairly easily measurable; we're dwarfing natural processes. Aside from natural seasonal variation the biggest natural contributor to atmospheric CO2 is volcanic activity, and the rate at which we're releasing carbon is completely unprecedented. You can figure it as equivalent to 1-2 Yellowstone supervolcano eruptions every year, or two Pinatubos per day. (the article quotes from a paper that I belive is available online but I can't find it at the moment).

The models are well-defined on the lower limit due to the physics of radiation; 3.7 W/m^2 increase per doubling of CO2 is a straightforward result of the Stefan-Boltzmann Law. That is equivalent to about 1 degree C global temp, and no one is worried about that. The issue is that water vapor is a much stronger greenhouse gas and you may have noticed that there's quite a bit of it lying around. Furthermore, air can hold exponentially more water vapor as it heats up. There's a lot of variation possible in the feedback loops but negative feedback is really unlikely.

Personally, I find the most useful way to approach the subject is to take a look at the history of climate science. Thousands of scientists did not wake up one day and accept the movement of the continents, neither did they accept that humans could have any affect on the climate without strong proofs. The Discovery of Global Warming goes over the history of global warming and has useful insights into what exactly a climate model is, and how even one-dimensional models can still tell us useful things even if their long-term predictions are not all that accurate

For a more detailed look into the science, you might check out Science of Doom, but a textbook on atmospheric physics may be more useful. Unfortunately, beyond the basics it starts to get complicated in a real hurry; unless you really want to start diving through papers and textbooks you will probably be best served by the IPCC report.

... Before that it can't, because Ta^4 - Tb^4 is a positive number so no net radiant energy is absorbed by (a) from (b). That means all the way up to the exact point thermal equilibrium is achieved, all radiant power is a result of electrical power, therefore the power input and power output are constant. It is not a "gradual" process. ... [Jane Q. Public, 2014-09-20]

So Jane claims:

electrical power per square meter = (s)*(e)*Ta^4

The actual answer is:

electrical power per square meter = (s)*(e)*(Ta^4 - Tb^4)

Since Jane refuses to include a term accounting for radiation from the chamber walls, Jane's equation is saying that no radiation at all is absorbed by the warmer source. Why?

... Since the chamber walls are COOLER than the heat source, radiative power from the chamber walls is not absorbed by the heat source. ... [Jane Q. Public, 2014-09-15]

Of course it is! Again, this is just Sky Dragon Slayer nonsense. Absorption doesn't work like Slayers imagine. It's controlled by the surface's absorptivity, which doesn't change if the source is slightly warmer or cooler than its surroundings. All that's required for the source to absorb radiation (from warmer or colder objects) is having absorptivity > 0. Since the source has absorptivity = 0.11, some radiative power from the chamber walls is absorbed by the heat source.

Jane's been regurgitating Slayer nonsense for years:

... Warmer objects cannot, and do not absorb lower-energy radiation from cooler objects. ... [Jane Q. Public, 2012-11-20]

Then how do uncooled IR detectors see cooler objects? How did we detect the 2.7K cosmic microwave background radiation with warmer detectors?

... explain how radiation that is of a LOWER "black-body temperature" will be absorbed by a body of a HIGHER black-body temperature. ... [Jane Q. Public, 2013-05-30]

... An object that is radiating at a certain black-body temperature WILL NOT absorb a less-energetic photon from an outside source. This is am extremely well-known corollary of the Second Law. ... [Jane Q. Public, 2013-05-30]

No, that's a Slayer fantasy. On the atomic scale, absorption of radiation doesn't depend on temperature because individual atoms don't have temperatures. Only very large groups of atoms have temperatures. Individual photons also don't have temperatures. Very large groups of photons from a 10C warm object have slightly different average wavelength curves than a -10C cold object, but they're very similar. This means that even if temperature somehow applied at the atomic scale of absorbing individual photons, an atom couldn't tell if a photon came from the 10C warm object or the -10C cold object.

... You took a badly-worded sentence or two and jumped on them as though Latour made a mistake. But his only mistake was

Nonsense. They are figures at at incident radiation of 1367 W/m^2, which is sunlight at 1 AU, for the very reason that it is an approximation of Earth insolation. So in fact it would make a good representative example of what Spencer's model is supposed to be all about. ... ESA gives observed values for integrated emissivity and absorptivity for aluminum. This is a good approximation and it is used in the real world for aluminum in a vacuum. [Jane Q. Public, 2014-09-03]

Those ESA absorptivities are for absorption of sunlight. Consider the first diagram here which shows that 6000K sunlight has much shorter wavelengths than the radiation from objects at the temperatures we're considering. In fact they hardly overlap. But the emissivities are for radiation emitted by much cooler objects. That's one reason why those ESA emissivities aren't equal to their absorptivities.

Here's a good explanation of this problem: "... white paint is quoted as having an absorptivity of 0.16, while having an emissivity of 0.93.[9] This is because the absorptivity is averaged with weighting for the solar spectrum, while the emissivity is weighted for the emission of the paint itself at normal ambient temperatures. ..."

If you really insist on gray bodies that's up to you; but I do not acknowledge that there is any legitimate reason to NOT use reasonable approximations of integrated absorptivity and emissivity. [Jane Q. Public, 2014-09-03]

Since the absorption values you indirectly cited are for absorption from the 6000K radiation from the Sun, that seems like a legitimate reason not to use those values in a thought experiment where nothing is at 6000K. Again, another reason is that we'd have to recreate MODTRAN to derive heat transfer between non-gray bodies where emissivity and absorptivity are arbitrary functions of wavelength.

And once we debugged that new MODTRAN clone, we'd have to test it in a simple case, like the case of gray bodies where emissivity and absorptivity don't depend on wavelength. So we might as well solve the simple problem first.

We might be talking past each other. What you're calling steady-state is what I'm calling equilibrium. Radiative thermodynamic equilibrium doesn't require all surfaces to be at the same temperature, it simply means that temperatures don't change with time. At radiative equilibrium, power in = power out, which also means irradiance in = irradiance out.

You USED this before to ASSUME all surfaces were at the same temperature! I quoted you saying it in a post above, and you referenced that passage just the other day. In fact this was the source of much of the misunderstanding here. ... [Jane Q. Public, 2014-09-03]

Once again, I never said that. In reality, I said that both sides of a thermal superconductor are at the same temperature. This was the source of much of the misunderstanding here, and you strongly objected to the notion of a thermal superconductor. Again, that's why I calculated the small temperature difference across an aluminum shell with finite conductivity.

That's also

... Since this person is not making any scientific argument anyway, but simply attempting ad-hominem, and saying "so-and-so is wrong" without ANY evidence (which is all he can do, because he doesn't have any), this was a completely pointless exercise on his part. He was simply making another attempt at dragging my persona through the mud. I can only conclude that was his only purpose, since he didn't make any actual, substantive arguments. [Jane Q. Public, 2014-07-25]

A real skeptic would be checking my calculations but Jane can't even acknowledge them. If the Slayers are right, why is Venus hotter than Mercury?

Mercury's daytime surface temperature is 350C while Venus has a nighttime surface temperature of ~470C.

... despite the fact that Venus is 87% farther away from the Sun than Mercury, implying sunlight 3.5x weaker.

... and despite the fact that Mercury's albedo is ~0.1 and Venus's albedo is ~0.65.

... and despite the fact that a "night" on Venus lasts ~58 Earth days, during which the temperature barely changes from that at "high noon".

... Since all atmospheres must get colder with altitude as kinetic energy is transformed into potential energy in a planet’s gravitational field, the lower atmosphere must be warmer than upper atmosphere, even if there is no radiation involved. This follows from the perfect gas law, PV = nRT. ... [Dr. Latour, 2011-11-06]

Riiiight. That's why the stratosphere doesn't exist. I've explained that long-term equilibrium surface temperature is determined by conservation of energy, not the ideal gas law. (If scientists were wrong, basketball players would have to dribble with gloves because the pressurized ball would have to be very hot.)

Many Slayers blame equilibrium surface temperature on pressure, which I call the basketball player glove fantasy. None of the Slayers at WUWT would answer this question: would Venus have the same surface temperature if its atmosphere were pure nitrogen, which isn’t a greenhouse gas?

I've even seen a Slayer convince himself that all objects have the same albedo, which I call the gray Oreo fantasy.

Will Jane explain the fact that Venus is hotter than Mercury using basketball player gloves, gray Oreos, or truly original groundbreaking science?

Quit repeating yourself, it's dull.

AGW could be falsified in a number of different ways, but why don't you disengage your oral-rectal interface and actually learn something about atmospheric science. You can't just bitch about a theory you don't like, you have to account for the observations it explains in some other manner.

There's a lot of good information that can be found on this site, and ScienceOfDoom has a pretty good (with some exceptions) eight-part series on why CO2 is an issue. Finally, you could actually read the IPCC reports. Understand that we're working from 200 years of observations, and that the properties of CO2 are extremely well known. We know very specifically what wavelengths of radiation it absorbs under various conditions. We can also measure this in the atmosphere directly. It is completely inarguable that a higher partial pressure of carbon dioxide will result in heat retention through absorption of outgoing long-wave radiation. However, if you wanted to try to disprove that, you could start postulating magic fairy dust, or a conspiracy of scientists. Those would be easiest. Next best bet would be that CO2 doesn't behave the way it is measured to behave both in the lab and via satellite. It could be that it only absorbs OLR when someone is looking. Lastly you could accept that CO2 does cause warming but find some other phenomenon which would offset this, and may I say good luck on that one. I am sure that you know enough to know that getting rid of excess heat in space is a problem; we have that problem on a planetary scale.

The AGW theory is the result of, as said, about 200 years of observations. But if you wanted to stick your fingers into the wounds, then head to the Arctic; it's melting like gangbusters. We are rapidly heading towards a future where large icefields will not exist. However, do note that while the fundamentals of CO2-related forcing in the matter of climate change are not in doubt, the effects of a more energetic atmosphere are difficult to predict. It's not an intractable problem, and it's relatively easy to get a ballpark estimate by modeling the atmosphere as a column of air, which is why we're talking about single-digit changes in global temperature per doubling of CO2 as opposed to an order of magnitude more or less.

You have a cognitive bias which is leading you to ignore or reject observations. If you accept the evidence for relativity, or quantum physics, or evolution, or plate tectonics, or the germ theory of disease, or stellar evolution, then you should either accept the scientific basis for AGW or find a better argument. Proceed from the evidence to your hypothesis and not the other way around. If you do not know the evidence, then you are unqualified to discuss it.

Anon for moderation.

Yes, a small change in the partial pressure will have a measurable effect, and this effect is relatively easy to calculate, to within an order of magnitude. The values for CO2-related forcing haven't changed that much in the 100 or so years since we first started calculating it. There is some uncertainty, but no one is talking about .2 C or 20 C per doubling.

The stratosphere is a complicated topic but I recommend that you start with the IPCC report and move on to Science of Doom. Were you just going to do this game of picking a random topic and saying that the science isn't predictive, or are you actually interested in the subject? Because really, you don't know enough to ask the questions that don't have answers, so pretty much everything that you're deeply ignorant about is going to have an answer, at least until such point as you know enough to actually get into the scientific literature.

It's okay, we understand if these things are too scary and full of math for you. They have charts and everything! There's not even anyone there to hold your hand and tell you it's all Obama's fault. But you don't have to think, learn, or understand if it's too hard for you. We would of course prefer in that situation that you shut the fuck up.

Anyone that can make it through an undergraduate text on atmospheric science and still maintain that CO2 does not cause warming is fooling themselves. One one side of this argument we have idiots who fundamentally do not understand what they are arguing against. Radiative transfer is not that hard, and if you're going to argue that the science is bullshit, then you should know the science. Not the global climate simulations, but the absorbtion spectra of various gases in the atmosphere, because those can be trivially measured. The effects of anthropogenic climate change are up for debate, that CO2 causes warming and that humans are really fucking good at generating it is really not. If you don't like it, prove me wrong.

You could start reading here, or pick up a real textbook. It might take you a whole afternoon. Be warned, it's chock-full of actual observations and -- dare I say? -- inconvenient truths.

Here are some statistics to show that, as pertains the Arctic, the Earth is measurably warming. I can tell you offhand that annual temperatures in Alaska have warmed by 3 degrees in the last century, and winter temperatures by 6 degrees. Southeastern Alaska is characterized by stable temperatures throughout the year, heavy precipitation, and a gradual transition from getting most of that as rain vs snow as one goes further north. Thus the warming is shall we say particularly noticeable to costal inhabitants. Another good measure of long-term climactic changes is the extent of permafrost.[pdf] Much of the ground in Alaska, and practically all the ground above the Arctic Circle is permanently frozen. Ice being less dense than water, if you happen to melt it, you create a subsidence and potentially a small lake. Either way, it's extremely disruptive to what little vegetation (or structures) there are that can survive on top of permafrost and hence easy to observe. Other good measures are the many glaciers, which I am told take thousands of years to form. 98% of all glaciers in Alaska are in retreat, and I mean visibly, over the last two decades. I lived in a fairly glacier-heavy area, and every successive spring brought more bare rock where once there was towering ice. The most dramatic of these was Columbia, of course, and I'm told that is not strongly linked to climate changes, but nine miles of ice melting in two decades is really an incredible pace.

I've recently been probing my ignorance of atmospheric science. I've found a couple fairly informative resources, including this more general introduction to the maths, and a more thorough examination of carbon dioxide's role as a greenhouse gas. It really doesn't take a great deal of learning to see that, aside from the observed warming trend, a higher partial pressure of carbon dioxide must result in increased heat transfer to the Earth's surface. There's really nowhere else for it to go. What happens from there is obviously a complex topic, but as you say, the glass jar experiments show pretty clearly that CO2 absorbs long-wave outgoing radiation. Where else do you imagine the heat goes?

Thanks for the link, although it doesn't actually explain whether the formula is derived from observation or from physical principles. As it turns out (with a bit of digging): both. It's an approximation that is sensitive to your choice of C and C0 (in IPCC: current and pre-industrial CO2 concentrations) and fits well to both empirical observations and theoretical expectations within a reasonable range of CO2 concentration. A detailed explanation can be found at http://scienceofdoom.com/2010/02/19/co2-an-insignificant-trace-gas-part-seven-the-boring-numbers/ .

There are many levels of scientific incompetence among climate deniers. The very lowest rung of which are the morons who believe that the greenhouse effect is thermodynamically impossible. Good grief, go pick up a textbook on radiative transfer. Or work your way through Science of Doom tutorials.

It's amusing to realize that if Latour was arguing for the greenhouse effect, you would treat his utter failure to defend his arguments with the utmost skepticism, but all your "skepticism" goes out the window when it's a guy on "your side". I'm sure you're also quite willing to rally around Spencer when he's arguing about climate feedbacks to the greenhouse effect, but throw him under the bus when he admits that the greenhouse effect exists.

There are many levels of scientific incompetence among climate deniers. The very lowest rung of which are the morons who believe that the greenhouse effect is thermodynamically impossible. Good grief, go pick up a textbook on radiative transfer. Or work your way through Science of Doom tutorials.

It's amusing to realize that if Latour was arguing for the greenhouse effect, you would treat his utter failure to defend his arguments with the utmost skepticism, but all your "skepticism" goes out the window when it's a guy on "your side". I'm sure you're also quite willing to rally around Spencer when he's arguing about climate feedbacks to the greenhouse effect, but throw him under the bus when he admits that the greenhouse effect exists.