20 Reasons To Be Skeptical of Human-Induced Global Warming

The IPCC admits that the initial greenhouse effect of CO2 is slight but I gather they claim that this small effect from CO2 is amplified by positive feedbacks. Water vapour is responsible for increasing the initial forcing from CO2 by a factor of about 3 (in the models). By my understanding, measurements have shown that ‘specific humanity’ has remained roughly the same (see Ole Humlum) as CO2 has increased.

The idea that natural CO2 and the CO2-sinks were initially in balance for thousands of years seems highly unlikely on the face of it to me because nothing in nature is ever in a state of fixed equilibrium. So it’s true that this is suggested by the ice-core data, but there is so much intrinsic uncertainty in paleoclimate ice-core reconstructions. I see a fundamental problem with paleoclimate data in that none of the measures and estimates that are taken can be standardized by reference to direct empirical observations. Skeptics have argued that the ice-core may be unreliable as a proxy for CO2 because it undergoes ‘fractionation processes’ that can underestimate true paleo-atmospheric CO2 values. Other paleo-climate data such as Stomata shows more variability, with CO2 as high as 459ppmv, but even Stomata may be unreliable due to local variability.

But does the mass-accounting ‘match up’ with the CO2 we have emitted? Humans have emitted about 2,000Gts of CO2 since 1850 according to the IPCC and the CO2 increase has been about 950Gts. The IPCC claims that about half has been absorbed by the sinks. It may sound counterintuitive, but Henry’s law makes it possible for the oceans to have absorbed the vast majority of our CO2-emissions while also at the same time contributing to the CO2 increase due to a temperature-change (as explained in reason #20). In fact, the oceans *must* have contributed something to the CO2 increase because we know that they have warmed.

 

I think 14C bomb spike is really useful. It highlights the short residence time on per molecule basis nicely. And I agree that the residence time for 14C, 13C, and 12C should be close to the same with the caveat that there is some preferential treat certain isotopes for certain processes. That's actually what makes the isotope analysis useful. But the bomb spike data doesn't really tell us anything about the exchange rates.

The Suess effect describes the fossil fuel signature pretty well I think. Plants have preferential uptake of 12C vs 13C in general. But a certain class of plant that is responsible for the largest stock of fossil fuels is even more preferential than the general case. So fossil fuels are depleted in 13C relative to the atmosphere. Then because 14C is radioactive with a half of about 5,000 years it's concentration in fossil fuels is rarified because fossil fuels are millions of years old. So when you have a low 13C-to-12C ratio being injected into the atmosphere at a rapid pace you expect the existing 13C-to-12C ratio to drop. And that's what we observe. Interestingly, because fossil fuels are also exhibit 14C depletion the injection of fossil carbon into the atmosphere would also lower the 14C-to-12C ratio as well assuming there were no anthroprogenic injections of 14C like with nuclear reactions.

The real issue here is with the longevity of the concentration which is not be confused with the longevity of a molecule. The only way to know this for sure is to pulse a slug of CO2 and observe how long it takes for the concentration to return to it's baseline point. Using a tracer isotope like 14C isn't useful because a 14C molecule could be getting replaced with 13C or 12C molecule. You'd see the tracer decrease relative to the other isotopes without seeing a corresponding decrease in the concentration. Fortunately we are running the best possible real-life experiment right now because we are in fact pulsing a quantity of CO2, which just happens to have a unique isotope signature, in the atmosphere. And based on both the changes in the isotope ratios and the mass accounting of the carbon the best model that matches the CO2 concentration for both preindustrial and postindustrial eras is one in which the half-life of the concentration perturbations are really long (possibly 100 years or even longer). Some studies show that it might take as much as 10,000 years before concentrations return to preindustrial levels. And the paleoclimate record is consistent with that hypothesis. For example, the last interglacial warming event prior to the most recent one saw a rapid spike in CO2 levels followed by a 100,000 year dieoff. The begs the question...how did CO2 levels spike so quickly but take so long to recover?

 

The recovery-time for CO2 levels in the paleoclimate record may not be representative of true paleo-atmospheric CO2 levels. As mentioned, the ice-core data suffers from fractionation processes such as the formation of clathrates and gravitational compression (forcing CO2 out of the ice to the surface over millennia) which may underestimate true levels. Stomata data (and chemical measurements – see Georg Beck 2007-09) show more variability in CO2. Also, I wouldn’t describe it as a “recovery-time”. The amount of CO2 in the atmosphere varies continually in accordance with a host of environmental parameters, such as temperature, biomass and partial pressure. The oceans regulate how much CO2 is in the atmosphere based on their temperature. As the oceans warm, CO2 is released into the atmosphere, and as they cool, more CO2 is absorbed by the oceans. So, what we’re observing in the paleoclimate record is not a “recovery-time” or adjustment time. The amount of CO2 in the atmosphere is simply rising and falling based on the temperature of the oceans.

Indeed. I agree. The δ13C value has increased from a pre-industrial value of around –7 to –8.3 implying that there is around 6% of anthropogenic CO2 in the atmosphere today. Because of this, isotopic measurements can’t be used as proof that humans have contributed 30% to the atmospheric CO2-greenhouse. Also, in my last post, I did mention that the amount of CO2 in the atmosphere is based on the temperature and used the Van’t-Hoff temperature-equation to calculate how much CO2 would have been outgassed into the atmosphere due to a temperature-change. I calculated just under 20ppmv from a 1°C temperature change – but other scientists have calculated much more. Jaworowski (1997) says: “The IPCC estimated that the temperature of the surface waters increased between 1910 and 1988 by about 0.6°C. A similar increase was observed in the surface air temperature in this period. Increasing the average temperature of the surface of the oceanic waters (15°C) by 0.6°C, would decrease the solubility of CO2 in these waters (0.1970 g CO2 per 100 g) by about 2 percent. The CO2 flux from the ocean to the atmosphere should be increased by the same factor; that is, by about 1.9 GtC/year. This is similar to the observed average increase of atmospheric CO2 in the years 1958 to 1968, of 0.73ppmv/year, which corresponds to 1.6 GtC/year. The measured annual atmospheric CO2 increases were higher in the next two decades (2.5 GtC/year and 3.4 GtC/year) which indicates
that changes in CO2 solubility in oceanic water were responsible only for a part of observed CO2 increases”.

I don’t follow your reasoning here. The decrease in nuclear-14C is not being measured relative to 12C and 13C.

 

I would like to just correct a mistake in my last post. Δ14C reflects the ratio of the abundance of 14C atoms compared to 12C atoms in a sample. For some reason, I was thinking that Δ14CO2 was measured based on how many 14C atoms the CO2 concentration has in it without being relative to other isotopes. After the 1963 test-ban treaty the number of CO2 molecules containing 14C atoms increased to almost +1000 per mil doubling the concentration and it has been steadily decreasing ever since as the 14CO2 molecules equilibrate with sources and sinks. I would think that the decrease in Δ14CO2 is a measure of equilibration not just for 14CO2, but for all CO2 in the atmosphere, as suggested by Tom Segalstad and Hermann Harde. Because the nuclear-14CO2 has been mixed indiscriminately with atmospheric 12CO2 and 13CO2, the rate of removal and equilibration for 14CO2 should be the same for larger the concentrations of 12CO2 and 13CO2. Even though there is more 12CO2 and 13CO2 in the atmosphere, because the nuclear-14CO2 has been mixed indiscriminately with the other CO2 isotopes, they should all be removed by the same proportions.

 

Your opponent seems to have gone home to lick his wounds. Good job.

 

Heh. Iamanonman to me seems very knowledgeable on AGW and I appreciate his input. This discussion has motivated me to look into ∆14C more and there are new things that I’ve learnt that I didn’t know before.

 

Your attitude I appreciated but I have run out of patience with the guy in my history. Good luck.

 

About the book "A Hundred Authors Against Einstein", Einstein said “Why 100 authors? If I were wrong, then one would have been enough!”. A Gish Gallup is a sign that you've got nothing, that you're tossing everything at the wall in the hopes that something will stick. If you had one good argument, then the one good argument would have been sufficient.

Let's go over the points of the graphic.

1. CO2 has a very low concentration, so it can't be a factor.

You refute this yourself with your later calculations of forcing, so I don't have to. Your arguments are self-contradicting. You say CO2 can't have any significant effect, then you calculate the rather significant effect that CO2 has.

2. Water vapor is the main GHG.

Red herring. That's always been taken into account. Water vapor is a feedback, not a forcing.

3. CO2 has a logarithmic forcing

Red herring. That's always been taken into account.

4. Some scientists "dissent" from climate sensitivity.

So? Most don't.

5. Notrickszone has papers.

And those papers look absurd. In the real world, about half a doubling (logarithmic) of CO2 has resulted in about 1.0C of warming, demonstrating a TCS of around 2.0C. ECS has to be bigger than TCS, yet all but one of those papers predict an ECS of < 1.0C. Those papers are clearly very wrong.

I suggest you go over every entry here, as it covers many of your arguments.

https://www.skepticalscience.com/argument.php

 

You say that the papers look absurd. I think you are being closed-minded. Real science is about applying critical reality-checks to what you think might be the truth. How do you know the papers are absurd if you have not read them? What you are doing is making sweeping assumptions without applying any critical reality-checks. That’s not science. The idea that doubling atmospheric CO2 will produce 1°C of warming is problematic because the amount of RF which a given amount of CO2 creates has not been established evidentially and is a matter of dispute at the present time. Based on the IPCC’s own equations, I have calculated a warming from CO2 of only 0.37°C without feedbacks and other scientists have calculated lower values (See the graphic below). You write: “Some scientists “dissent” from climate sensitivity. So? Most don't”. How fascinating. But how did you become a spokesperson for all scientists worldwide to be able to say what the majority of them believe regarding climate sensitivity?

I did not say that CO2 could not be a factor. I said the warming from CO2 is trivial. What calculations are you referring to?

That’s a distorted picture of the true situation, I’m afraid. Water vapour is produced by the evaporation of surface water and that evaporation occurs due to various causes — not just by the radiance from atmospheric CO2. It is therefore as much a primary forcing in its own right as CO2 and is not just a feedback to CO2. Indeed, it is not a direct feedback to CO2 at all, since its mean atmospheric concentration is affected by other factors besides CO2 as well, such as condensation rates, precipitation rates, air-temperature, air-pressure and so on.

 

But how do you know that this 1°C of warming is due to CO2 and not some other natural factor unrelated to CO2? Aren’t you jumping to conclusions here?

 

How do you know they're right, given you haven't read them? How do you know the mainstream papers are wrong, given you haven't read them? You're clearly pushing a double standard.

Those papers predict a result which is contradicted by observed reality. It doesn't matter how elegant your theory is, if it's contradicted by the real world, it's wrong.

On the contrary, seeing if your results match reality is the most critical reality-check. I'm doing it. You're not.

You have clearly calculated incorrectly, because observed reality strongly disagrees with your calculations. You can ask me to believe you over my lying eyes, but I'm going to decline.

There are around a thousand papers referenced here, and that's the tip of the iceberg. In contrast, you put forth a small list that's mostly very old papers, works by non-scientists, paid shill papers, or papers that NoTricksZone just lied outright about.

https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter12_FINAL.pdf

That's also not science. It's the equivalent of saying "Well, we can't be absolutely sure it's not fairy magic changing the climate, therefore we have to assume that fairy magic could possibly be the cause, therefore the mainstream science should be ignored". You're waving your hands around wildly and invoking some mysterious unknown. And being you don't use that "But we don't know with absolute 100% certainty!" standard in any other branch of science, it's hypocritical for you to invoke it here.

If your theory is that something besides greenhouse gases are changing the climate, then state precisely what those factors are, then provide evidence to back up that claim. That's science.

The erroneous calculations where you predict warming of 0.0046°C. Certainly measurable.

If water vapor was a primary forcing, then more water vapor would cause more heat which would cause more water vapor which would cause more heat, until the earth boiled. As water vapor self-corrects back to a level based on temperature, it's a feedback.

All of those things even out in the long run, to a level based on temperature. The only thing that changes water vapor levels in the medium-long run is temperature.

 

That's very scientific of you.

 

No, just experience. ...

 

Hold on. I ask you how do you know that the 1°C of warming was caused by CO2 and you respond by saying that I am “waving my hands around wildly and invoking some mysterious unknown”. You got all that from a question I asked you? What a masterful performance in the art of prevarication!

Clouds can explain some of the warming. Cloud-cover is assumed to have decreased by around 1.56% (Warren et al 2012) between 1971-2009 and based on Reed’s (1977) Flux Formula that relates to an increase in absorbed short-wave solar radiation of about 3 W/m2. For more information, see reason #12 in my blog-post.

Why are they erroneous as calculations?

Regardless of how many papers the IPCC cite, I think the essential question at issue is that of how much radiation enhancement the CO2 greenhouse is actually producing. How many of those thousand papers support the notion that human CO2-emissions are main the cause of global warming? A citizen audit of the IPCC’s AR4 report found a staggering 5,600 “grey references” which included NGO-pronouncements, newspaper clippings and magazine articles. In terms of its scientific quality it appears to be dishonest rubbish to me.

Water vapour is in the incorrigible habit of turning into clouds, which reflect away more energy of incoming sunlight than they re-radiate back down to Earth by way of positive feedback.

I can only say that I disagree for the reasons explained in my previous post. If the amount of water vapour in the atmosphere was determined by temperature and atmospheric CO2 (while ignoring other factors) then how do you explain the lack of increase in atmospheric specific humidity? According to the IPCC’s theory, as CO2 warms the surface this should increase evaporation-rates and dump more water vapour into the atmosphere. But the amount of water vapour in the atmosphere has remained roughly the same. There is no direct, one-to-one, linear causal relationship between CO2 (or temperature) and water vapour and the graph in the link (here) attests to that.

What “observed reality” are you referring to? And why are the calculations wrong?

I am not claiming that they are all right. Just that there are a number of papers that disagree with the IPCC on climate sensitivity. Oh, and I have read the papers (or at very least the abstracts and summaries).

Well what evidence do you have that human CO2 emissions are 1) increasing atmospheric CO2 and 2) are the primary cause of global warming.

 

You've lived long enough to understand climate change from personal experience?

 

No, I have argued enough to know it is pointless.

 

It's pointless because your argument that man is the primary driver of climate is feckless

 

If you're going to claim to have debunked the mainstream science, you should understand first what the mainstream science is. As you've only looked at conspiracy sources, you don't.

We see the smoking gun for greenhouse gas based warming in multiple ways. We directly measure the stratospheric cooling, the increase in backradiation, the decrease in outgoing longwave radiation in the greenhouse gas absorption bands. AGW theory explains that. If you want to taken seriously, you theory has to explain it as well. Your "It's natural!" theory does not, therefore your theory is wrong.

Changes in clouds are a feedback from warming, not a cause. If you want to propose that cloud changes initiated the warming, you have to identify what caused the clouds to change, aside from temperature, and you also have to explain why such cloud-initiated warming hasn't been observed in the past. Nobody has done that. Cosmic ray theories have been debunked, being that cloud changes and warming have gone in the opposite direction of what cosmic ray theories predicted.

Post #12 covered it well. Trying to keep the length here reasonable.

We measure back radiation directly. It's increasing. For example, Evans (2006):

https://ams.confex.com/ams/Annual2006/techprogram/paper_100737.htm
---
In comparison, an ensemble summary of our measurements indicates that an energy flux imbalance of 3.5 W/m2 has been created by anthropogenic emissions of greenhouse gases since 1850
---

So, you asked for references, I showed them to you, and you reply with conspiracy blog claims. I also note that deniers tend to rely almost entirely on those "grey references" that you say are rubbish. I note that you ignore the great majority of the sources that aren't "grey references". And I note you retreated from your "How do you know if you haven't read them?" line of reasoning when it was pointed out you haven't read any of the studies you say are wrong.

Not that simple. Cloud formation is affected by temperature and winds, and high and low clouds work differently. The best estimates is that cloud feedback from warming is slightly positive. However, on the whole, cloud effects are currently negative, due to human-created aerosols.

I'd point out your claim is incorrect, being that specific humidity has been rising.

https://www.skepticalscience.com/humidity-global-warming.htm

 

It's not just my theory though (see Roy Spencer), and I don’t have to explain how natural variation works. It is the accepted Null Hypothesis in the scientifically skeptical community that is assumed as the a priori cause of all climate phenomena on the grounds that it had to be their primary cause before human industrial society existed and we have no reason to think that it has ceased to operate over the last one-hundred years.

How did Evans (2006) measure the back-radiation from greenhouse gases? What instrumentation did he use? Evans states that there has been a net “energy flux imbalance of ~3.5 W/m2 by anthropogenic emissions of greenhouse gases since 1850”. However no-one was measuring atmospheric radiative forcing of CO2 and methane in 1850, were they? Therefore, these figures are not the results of empirical observations but are speculative conjectures. They are not proven facts. Evans must have used a model to estimate the forcing from greenhouse gases in 1850 such as HITRAN or MODTRAN.

In climate science the alternative possible drivers of observed global temperature changes are innumerable and climate scientists have hardly begun to explore the tip of this vast iceberg as yet. Clouds are a forcing in their own right and there are numerous factors that can affect their formation, such as Pacific Decadal Oscillation (PDO), ENSO, precipitation-rates, condensation-rates, etc. But I think anyone who claimed to know, or to be able to calculate the complex energy interactions involved in these turbulent processes would be a fraud.

How is the calculation erroneous? The warming of 0.0046°C from 0.0025 W/m2 is a straightforward application of the Stefan-Boltzmann law to the question of how big a temperature increase would be produced directly at the Earth’s surface. My reasoning was as follows: Initial surface temperature of Earth (T0) = 288K. Using the Stefan-Boltzmann law we get: Initial surface radiance (I0) implied by T0 = 390.1069 W/m2. Increment of irradiation from whatever source (dI) = 0.025 W/m2. Therefore, new surface radiance (I1) = 390.1069 + 0.025 = 390.1319 W/m2. Using the Stefan-Boltzmann law again (in reverse this time) we get:
New effective surface temperature (T1) implied by I1 = 288.0046K. Temperature increase on T0 (i.e. dT) = 288.0046 – 288 = 0.0046C.

It’s not my claim. It’s what that particular data-set shows.

The graphic from the IPCC looks impressively scientific at first sight but is it correct? And how might we tell? The IPCC’s graphic appears to underestimate the forcing from clouds. There are studies that show that a decrease in cloud-cover has led to a large increase in short-wave radiation impinging on the surface. The IPCC don’t appear to have taken this into consideration. Below are a few of the studies. Also, the amount of radiative forcing in the IPCC’s graphic above is based on the Arrhenius logarithmic equation. The IPCC’s Arrhenius equation predicts a radiative forcing of 0.31 W/m2 from a 22ppmv increase in CO2 from 370ppmv
to 392ppmv whereas from the same CO2 increase Feldman measured a forcing of 0.2 W/m2. The IPCC’s equation appears to overestimate the amount of radiative forcing from CO2 by a factor of 1.55.

 

I was on vacation with my family. My lack of response was due to my desire to spend time with my family. I happen to think Nathan-D is a critical thinker so I too will echo the good job vibe his way.

 

Regarding point #10...

Our CO2 concentration data comes from multiple ice core sites and we have other proxies for the concentration as well. I'm not saying you should trust the dataset's 100%, but there is enough overlap in the various datasets to establish a pretty good consensus of the concentration back to about 1 million years ago. Prior to that the datasets get really noisy and coarse grained. Time steps in datasets prior to 1 MYA can be as much 100,000 years apart and often represent the average over that period. But, during the glacial/interglacial era in last 1 million years we have a pretty good idea of what the concentration was within a reasonable margin of error.

 

Regarding point #11...

No one is claiming that the warming rate is unprecedented over all of Earth's history. Scientists are claiming that it is very usual and likely unprecedented during this interglacial period which goes back 10,000 years ago. Also, the IPCC acknowledges that nearly all of the warming prior to 1900 was natural likely getting a boost from a solar grand maximum and reduced volcanism. Starting around the 1900 the anthroprogenic effect began ramping up slowly, but even then most of the warming prior to 1950 was likely natural again likely due to solar and volcanic activity. It wasn't until WWII that the anthroprogenic effect began dominating. And keep in mind that the equilibrium climate response ECR of pulse of CO2 takes about 30 years (give or take but probably more) to play out due to the inertial lag of the oceans. So the effect of that 770 gigatons of emissions between 1975-2009 won't be fully realized until 2040 or beyond. And our emissions today in 2018 won't be fully incorporated by the climate system until 2050 or beyond. It takes a long time for the climate system to equilibriate to a specific pulse of CO2.

 

My last few replies have been a tad bit too rushed. Anyway, I wouldn’t know how much overlap there was. Jaworowski 1992 says: “The ice-core data from various polar sites are not consistent with each another and there is a discrepancy between these data and geological climatic evidence. One such example is the discrepancy between the classic Antarctic Byrd and Vostok ice cores, where an important decrease in the CO2 content in the air bubbles occurred at the same depth of about 500 meters, but at which the ice age differed by about 16,000 years. In an approximately 14,000-year-old part of the Byrd core, a drop in the CO2 concentration of 50ppmv was observed, but in similarly old ice from the Vostok core, an increase of 60ppmv was found. In about ~6,000-year-old ice from Camp Century, Greenland, the CO2 concentration in air bubbles was 420ppmv, but it was 270ppmv in similarly old ice from Byrd, Antarctica”. My main issue with the ice-core data is that they may underestimate past CO2 concentrations for reasons already mentioned. Measurements have shown that the surface-snow underestimates atmospheric CO2 by 20-50%. At the Pionerskaya and Vostok stations in Antarctica the CO2 in the surface-snow was 160ppmv and 240ppmv respectively while the actual atmospheric CO2 level at the time was 310ppmv (Jaworowski et al 1992). Stomata-data contradicts the ice-core data and shows more variability in CO2 than the ice-core (see image below). Chemical measurements contradict the ice-core data as well. Furthermore, it is thought that high-order C3 plants die below 250ppmv. The ice-core shows CO2 at 180ppmv for many thousands of years. According to McKay 1991 and Segalstad 1998 the photosynthetic metabolism of high-order C3 plants cease below 250ppmv and they would go extinct “but this has not been recorded by paleo-botanists (Manum 1991)”. So, CO2 rising to unprecedented levels is not a known fact in my view. It is at best an uncertain conjecture that one may, or may not think is justified depending on one’s chosen criteria of credibility.

 

Vacation huh. Did you take planes trains or automobiles? All of the above? How much C02 did your vacation put into the atmosphere?

 

Yes. I took a plane and rented a car. My activities almost certainly led to carbon emissions, but I'm not sure how much.