## Thursday, September 11, 2014 ... //

### One-half of CO2 doubling achieved

Detectable impacts on the climate are yet to be seen

When the CO2 level in the atmosphere surpassed 400 ppm a short time ago, many alarmists would celebrate this symbolic achievement. Oh, the CO2 concentration is so high! It's a signal from the heaven, a shot from the Aurora telling us to start another world revolution because our previous one, that of 1917, has already faded away and it wasn't enough for us, anyway. The number is so round, and so on. Of course, nothing new happens when the CO2 level reaches 400 ppm – it's just another number that only looks special because of an arbitrary decadic numeral system we happen to use today. The Earth has seen concentrations around 6,000 ppm as well and 4,000 ppm would be just fine for all life forms we know today. By far the closest worrisome CO2 concentration is 150 ppm in which most existing plant species stop growing (ice ages have only forced them to easily withstand 180 ppm or so).

Another numerically special value of the concentration was achieved two years ago or so but unlike 400 ppm, it wasn't hyped by anyone. The hypothetical effect of CO2 on the temperatures (well, almost certainly real effect theoretically; hypothetical from an empirical viewpoint because the effect is so incredibly weak) is often quantified – converted to numbers – when we talk about the "climate sensitivity", i.e. the increase of the global mean temperature caused by a doubling of the CO2 concentration.

The doubling defines more natural benchmark values of the concentration because it suggests that we should look at the behavior of the temperature assuming the exponential growth of CO2. That's natural because the temperature increase is approximately (very accurately) proportional to the logarithm of the CO2 concentration increase (thanks, John). Consequently, every time you double the CO2 level, the temperature increases by the same amount (ignoring non-CO2 drivers). The global mean temperature as a function of the CO2 concentration is$T(c) = 14.5^\circ {\rm C} + {\rm sensitivity} \times \frac{\ln (c/280\text{ ppm})}{\ln 2}$ The temperature 14.5 degrees Celsius is the holy "optimum" global mean temperature that the climate alarmists want to see forever (yes, they will also protect our blue, not green planet from future ice ages when the temperature would otherwise drop by 8 °C as many times in the past) because it was how things probably were in 1750 although no one can really reconstruct the temperature in 1750 with a sub-degree accuracy (and even today's "global mean temperature" depends on so many technicalities that it's fair to say that it isn't defined at a sub-degree accuracy, either). The ratio of logarithms may also be written as the "base two logarithm" but I wanted to use basic functions only. Note that $$\ln 2\approx 0.69315$$.

The coefficient "sensitivity" is theoretically equal to 1.2 degrees Celsius if we ignore all the feedbacks. The total figure when feedbacks (especially those related to various forms of water in the atmosphere) are included is unknown and it may be higher or lower than 1.2 degrees Celsius. One of the unjustified assumptions of the climate change ideology is that the full figure has to be higher. The higher value of the climate sensitivity you defend, the greater influence over the climate alarmist paramilitary movement you achieve. If you believe that the value of the total climate sensitivity is below an offensive threshold, you are a heretic. The offensive threshold used to be 3 degrees Celsius but the alarmists were forced to lower the threshold of heresy to 1.5-2.0 degrees Celsius because those values are obviously consistent with all the known data (and probably still overestimates).

The CO2 concentration was around 280 ppm sometime in 1750 as well as in all interglacials. It has grown to 400 ppm today and the growth will continue, reaching the doubled value 560 ppm sometime after 2080. That's just a result of estimates and projections, no one really knows whether the growth of CO2 will accelerate or decelerate but the growth not too far from the increase in recent years sounds sensible.

When "we" reach 560 ppm after 2080, the ratio of logarithms in the formula above will be equal to one. That generates a certain increase of the temperature given by the climate sensitivity. When do we reach one-half of the climate sensitivity? Well, the concentration at that moment isn't the arithmetic average of 280 ppm and 560 ppm. Because of the logarithm in the formula, the "middle concentration" is the geometric average of 280 ppm and 560 ppm. In other words, the half-way concentration is$c_{0.5} = \sqrt{2}\times 280 \text{ ppm}\sim 396\text{ ppm}$ and it was reached sometime in 2012 or 2013. Now, we may compare the world in 1780 when the CO2 concentrations started to microscopically deviate from the natural background with the world in 2014. Lots of things have changed but the climate doesn't seem to be among the things that have changed and we would notice. It becomes increasingly hard to reconstruct the temperature in the distant past but it seems sensible to assume that the temperature growth rate due to CO2 was negligible before 1850 and since 1850, we could have measured the temperature sort of well and the total increase from 1850 was something like 0.7 °C. (Indeed, it's the same number we would quote 15 years ago, and it's so for a simple reason: there has indeed been no warming at least for 15 years.) Let's assume that Nature didn't matter much so the increase between 1780 and 2014 was 0.7 °C.

Imagine that you get the opportunity to meet your great great... grandmother who lived in 1780. You want to update her, tell her about all the interesting things that have taken place between 1780 and 2014. There are lots of things to say, aren't there? Aside from your family tree, wars, scientific discoveries, fashion etc., you may also mention the climate change. "Granny, the most important thing I want to tell you is that the climate has changed. More precisely, the global mean temperature has grown by something like 0.7 °C in those 230 years. It's sort of horrific. Please tell all the men around you to stop the steam engines and everything that uses some coal or oil."

That alarmist-descendant didn't have to ask her for that because the granny was a herbalist, a witch, and a Luddite, anyway.

That's what some of the real alarmists would tell their great great... grandmother during the short encounter. The old lady would still have time to prepare a herbal tea in order to cure their self-evidently sick brain. "Aren't you feeling ill?" she would rightfully and kindly ask her great great... grandson. (Did you see the research showing that all Ashkenazi Jews are 30th cousins of each other? They're said to have started from a population of 300 people 800 years ago.) I say "rightfully" because the great great... grandmother lives in a village where the temperature goes up and down by 10 °C every day and the maximum and minimum reached each day changes by additional 10 °C within most intervals that are several weeks long, too. She knows the seasonal cycles rather well (she had no air-conditioning system and a lot of work involving wood was needed for the heating) and she's heard about some folks who have visited Africa where the temperatures are much higher – and perhaps some visitors to Siberia or the polar regions where the temperature may be below –50 °C. She also knows that it was cold during the Maunder minimum, the Little Ice Age, but that the Hussites used to steal wine on the vineyards of Prague of the 15th century where everyone has to drink beer today (not yet Pilsner beer) because it's so cold. None of her thermometers may measure the temperature with a sub-degree accuracy and she can't feel sub-degree temperature changes by her skin, either. Intrigued by the general topic of the weather, the granny gave the descendant a lecture about the optimum weather for the tomatoes (and some secret herbs used in her liquors) in her garden but the guy from the future stopped her because he is only interested in the looming global cataclysm.

Instead, her great great... grandson tells her that one of the most important things that would occur in the next 230 years is the increase of the average temperature including all places on the globe (mostly completely irrelevant places) by 0.7 °C. What a disappointment. She would rightfully be disappointed by the quality of her descendants. She used to expect at least a sophisticated male witch and what she got was a picky hysterical bitch, instead. "Only this much after 10 generations? I and my husband worked hard to create this grid of 1,024 cousins of Alexander's age and all we got was 0.7 °C of warming. Our family is going to go to a lavatory," she would complain to her husband, the alarmist's great great... grandfather.

"Has most of the population before 2014 starved to death or why is it important?" the granny would ask again. The alarmist, nurturing some traces of conscience and subconsciously aware of the rising population between 1780 and 2014, the increased life expectancy, and the greening planet, decided to avoid straight lies so he answered: "It almost did!"

Off-topic: the Czech prime minister Sobotka has outlined new rules of the English grammar and pronunciation for all left-wingers in Europe and America. Deher Franz, on behalf of the social democratic, whether you're Scottish or Polish, it's never late to polish your English. His socialist predecessor George Quimby Paroubek's English was more polished.

Now, imagine that the alarmist (yes, of course that the chicken little is Alexander Ač who liked this essay so much that he has sent it to his friends on Facebook) meets his great great... grandson who lives in the year 2084. Regardless of the feedbacks, the temperature difference caused by the rising CO2 between 2014 and 2084 is the same as it is between 1780 and 2014. The alarmist would say: "I just met my great great... grandmother in 1780 but she refused to stop the steam engines by a suicide attack and gave me a herbal tea instead. So the CO2 would be rising all the time between 1780 and 2084. Are you still alive? You must be burning!"

Needless to say, the alarmist's descendant would inform his ancestor that he is doing fine because one of the intermediate members of the dynasty got a brain transplant in 2050 which cured him of the alarmist seizures. (He didn't explain how the surgery could have fixed the genetic alarmist pre-disposition of the family.) Otherwise the difference between the temperatures in 2084 and 2014 (the part caused by CO2) is the same as the difference between the temperatures in 1780 and 2014 (the part caused by CO2). It is negligible. It doesn't deserve to be mentioned among the top 500 important developments between 2014 and 2084.

Because we know that the temperature increase from the "first half-doubling" was about 0.7 °C, we may estimate the the temperature increase up to 2084 will be the same and the climate sensitivity could be around 1.4 °C if all the warming was due to CO2. The latter assumption is probably unrealistic because a part of the warming, perhaps almost all of it, was due to other, mostly natural reasons. The actual sensitivity may be smaller than 1.4 °C. However, it may be larger than 1.4 °C, too – it is conceivable but less likely that we got a warming even though the natural contributions were working hard to cool the globe. They could have been beaten. (I wrote that it was "less likely" because if you know that $$A+B$$ is positive and $$A,B$$ are mostly independent of each other and have an unknown distribution centered at a finite value, it's more likely for $$A$$ to be positive than negative, and it's more likely for $$B$$ to be positive as well simply because $$A+B$$ is positively correlated both with $$A$$ and $$B$$.)

There are many unknowns and only probabilistic claims may be made and even those are usually subtle. However, it's still possible to rigorously prove some definite statements that are not of probabilistic nature. For example, the following statement follows from the assumption that the dependence is logarithmic and the warming between 1780 and 2014 was 0.7 °C:

The temperature increase in 2014-2084 will be at most 1.4 °C – or most of the temperature changes between 1780 and 2084 are natural in origin.
I could be more specific what I mean by "most" and which "temperature changes" are evaluated to decide whether "most of them" were of natural origin – there are many specific versions of this proposition that may be proven – but they share the general point and it is the following:
Either you admit that the temperature changes caused by CO2 are negligibly small as the observations in 1780-2014 indicate; or you say that the period 1780-2014 only saw a negligible temperature trend because the CO2 effect was cancelled by natural factors. But if you say so, it follows that the natural factors are at least equally important to CO2 and they may decide about the future and beat CO2, too.
You just can't have it both ways! Observations show that the "global warming" is negligible and you can only argue that there "should have been much more" if you admit that there are other very strong factors unrelated to CO2 – but those will prevent you from predicting the future temperature change and even its sign.

Alarmists, indefinitely trying to invent rhetorical tricks that would imply that a dangerous climate change is looming, find themselves in between a stone and a hard place. On one hand, they don't want to admit that the climate sensitivity or the warming rate is negligible because they realize that such an admission would reveal that they are promoting an ant to a global problem. On the other hand, they can't really claim that the underlying trend caused by CO2 is much faster because that would imply that their predictions have already failed, or they need to admit factors that are completely beyond their control.

There is no way out. If your job is to sell a self-evident lie, you are in trouble. Different alarmists are leaning towards one side of the trade-off or another. Many of them are often changing the strategy. But almost all of them keep on denying the fundamental conflict between the observations and the very point of their ideology and let me phrase the conflict again, in slightly different words:
The empirical data make it clear that there can't be a predictable yet high global warming. Either the CO2-induced warming is predictable, in which case the negligible increase before 2014 must be a good estimate; or the CO2-induced warming is high in which case one needs other, equally large factors that were canceling it, and the future is unpredictable because of these factors!
The climate hysteria has considerably weakened in the last 5 or so years. But it's still around and most alarmists are working hard to obfuscate things, observations, arguments, and calculations that are obvious to the naked eye. However, the moment when the CO2 concentrations surpass 560 ppm sometime in the future – and the greenhouse effect due to CO2 will have reached the level of "one doubling" – will be exactly as unspectacular as the moment when "one-half of the doubling" was silently surpassed one or two years ago. Nothing qualitatively changes at these elevated but still amazingly low CO2 concentrations and even among the minor things that change when the concentration becomes this high, the effect on the temperature (or even, more generally, the climate) is one of the most negligible consequences.

#### snail feedback (30) :

Never underestimate the ingenuity of warmists. The temperature is rising? Warming! The temperature is not rising? Warming has never been about temperature.

Lying once started is difficult to stop.

OK, I know that they're capable of presenting arbitrarily dishonest verbal exercises but I don't really believe that someone buys such dancing - except for those who have a vested interest in this nonsense to continue.

Given everything we know, isn't it far more plausible that the feedback is negative? I seldom see this argument made in the media.

Yes, I definitely think that a negative value is more likely. Positive feedbacks when they grow sufficiently strong induce runaway behavior, exponentially growing instabilities, and positive (especially positive and high) feedbacks that nevertheless avoid this (empirically wrong) prediction are rare because the feedback coefficient has to belong to a narrow interval.

You said "The temperature increase in 2014-2084 will be at most 1.4 °C – or most of the temperature changes between 1780 and 2084 are natural in origin."

I don't understand this statement. Do you mean from 1780 to 2084? Why would the temperature increase in the next 70 years be twice as much as the temperature increase over the last 233 years? Especially given the natural log nature - which means each additional ppm has less effect than the previous one.

If you statement is correct - than the total temperature increase from 1780 to 2084 is 2.1C.

So based on this article and your other writings, I assume this was a mistake and you meant the total temperature increase to 2084 would be at most 1.4C.

Am I missing something?

Dear Rick, I was talking about a doubled warming rate in the next period of doubling because with a doubled value, one-half of it would be the piece predicted from the previous doubling - the observed 0.7 deg C - and additional 0.7 deg C would be a deviation from that log formula.

As I said, there are many quantities to calculate but the general conclusion is that a warming "much greater than 0.7 deg C" in the next doubling is only possible if the natural contribution were canceling - and therefore was equally strong - the man-made contribution in the previous doubling.

"That's natural because the temperature increase is approximately (very accurately) proportional to the logarithm of the temperature CO2 increase."

The thing about both positive and negative feedbacks is that they can be dependent on 'reservoirs' which makes them temporary. So for example, the (hypothetical) melting of the polar icecaps provides a definite positive feedback by albedo, but one that runs out if the icecaps completely melted. Similarly, ocean currents can provide a negative feedback as they sink heat, but one that is limited when the currents 'burp' out the heat again (decadal oscillations). So it seems to me that whether positive or negative feedback dominates at any time depends on how filled the reservoirs are which govern the feedback. One can switch from one to the other being dominant, and these reservoirs can change historically. Personally, I would be happy to say the climate sensitivity is 1.4 - 2.0 C, but maybe the present negative feedback reservoirs will run out, and the positive feedbacks will take over unchallenged, which will increase the sensitivity again. Albeit temporarily.

I would add a yet another scenario to the two you discuss, namely, that all or most of the warming observed between 1780 and 2014 was due to natural causes, other than CO2, that is, gradually increasing solar activity that peaked throughout most of the 20th century, especially towards the end of it, and ocean oscillations that are driven by solar activity albeit with some delay, due to the ocean's vast heat inertia. In this case, the CO2 effect would be smaller still or none--the rise in its atmospheric concentration due mostly to ocean and soil outgassing in response to solar heating.
It may even be that the CO2 effect may be cooling rather than heating. How so? Well, this may be happening due to atmospheric convection that would bring CO2 higher up, where it would radiate heat into space more effectively. The complications brought into the picture by real processes in the real, as opposed to modeled, atmosphere may well defeat the tiny warming effect that CO2 is claimed to have.

A lot of academic types just don't like consumer capitalism. They have disdain both for the entrepreneurs and businessmen who make it work, and for the Walmart shoppers who buy the product.

With the exception of snowball earth, has the global temperature ever gotten completely out of kilter?

Well, ice ages and interglacials which alternate several times each 100,000 years differ in temperature by 8 degrees Celsius... It is not small. Astronomical Milankovitch cycles drive this dynamics.

On the other hand, it is far from clear whether the Snowball earth saw too different global mean temperature... the equator could have been as warm as during the ice ages if not today...

The temperature differences are more important for the character of the climate than the average temperature...

We need only invert our thermometers to reverse the progression, putting it back the way it was. Warm less saline water sinks into the oceans preventing planetary temperature rise as Global Warming proceeds. By prohibiting fueled civilization we can preserve it.

A major solar storm is due in two days. Pop goes the weasel re inductance as the magnetosphere billows. If you are aboard ISS FUBAR, it is natural radiation that is cooking you.

An equation, with only two drivers as independent variables, explains measured average global temperatures since before 1900 with 95% correlation, calculates credible values back to 1610, and predicts through 2037.

Search AGW unveiled for the drivers, method, equation, data sources, history (hind cast to 1610) and predictions (to 2037).

Search consensusmistakes to find out why thermalization makes CO2 change NOT a driver.

"A lot of academic types just don't like consumer capitalism"

That may or may not be true, but it doesn't matter what anyone thinks about consumer capitalism, the effect of CO₂ on planetary temperature is precisely the same.

If it's so likely polar ice caps will be able to withstand CO₂ as high as we've pushed it, why isn't there a single previous example of them doing so in Earth's history?

lukelea, you are exactly correct.

It does not occur to Paul Krugman or Thom Friedman that their well being comes from the actual value of the products of businessmen.

The inventors of the transistor, and the computer operating system, gave a thousandfold added-value leverage to smart people of today, compared to labors of the past.

The added-value that Krugman's writing has given to anybody at all today, is next to zero.

The 400,000 should think of how they can add value to the transactions of ordinary people...

There is, and several. The best example is the late Ordovicium. Durinf that time there was an ice age so strong we call it 'snowball earth'. However, CO2 levels in the atmosphere were almost 10 fold of what they are today.

I tend to think the temperature is cycling about the equilibrium point. So in the 90's the temperature was above equilibrium and 15 years from now the temperature will be below equilibrium. This would be true if heat uptake in the ocean were an under damped process. I'm inclined to believe there is very little heat left in the pipeline.

The figures here (specially from slide 4 on) say that ocean heat content is increasing and is explains the observed increase in sea level http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/
But heat isn't temperature and what that implies for temperature I'm not sure.

Heat isn't literally temperature but all these heat figures are linear combinations (integrals of profiles) of temperatures (and their changes)!

"The best example is the late Ordovicium"

I think you're trying to say "Ordovician". Yes! There was a very brief ice age at the end of the Ordovician, from 445mya to 443mya.

How do you know what CO₂ was at the time?

What fault do you find in detailed measurements that suggest CO₂ dropped to almost zero during the late Ordovician glaciation?

www.geology.ohio-state.edu/~saltzman/youngetal_2010.pdf

reader Antonio (AKA "Un físico") said...

Hi Lubos, if you want to discuss about the validity of the climate senitivity value, we can exchange some emails. My analysis about climate sensitivity is on pages 5,6, & 7 of my pdf at: docs.google.com/file/d/0B4r_7eooq1u2TWRnRVhwSnNLc0k/
Regards, Antonio.
PS: I have not been following your web site (only, recently, a guy with the nick "eklecticus" cited your site).

You are using a disputed paper. Even another one is trying to talk 20 fold down to 4 fold, but even then you have a big problem to explain things:
http://wattsupwiththat.com/2010/08/10/study-climate-460-mya-was-like-today-but-thought-to-have-co2-levels-20-times-as-high/

The accepted one in the geological world, based on lots of data, all around the world, is this one:
http://www.geocraft.com/WVFossils/Reference_Docs/Geocarb_III-Berner.pdf

Your rhetorical question is vastly oversimplified. By what mechanism would CO2 vary on its own enough to allow the past to become a valid experiment about climate sensitivity to CO2 variation? A massive CO2 asteroid? No such thing! Instead, CO2 was along for the ride as temperature swung about due to many influences such as asteroids, sudden evolutionary developments of industrial capacity microorganisms, and just general fluid dynamic chaos coupled to sun and solar system changes. But today we suddenly *do* have an experiment running and the results are already in, by unnaturally boosting CO2 concentration so suddenly, and finding utterly no trend upswing in the strict linearity of both the oldest real thermometer records and the oldest tide gauge records.

The oldest thermometer records are here, with climate treaty Copenhagen thrown in for laughs:

http://s24.postimg.org/498mmzb6d/2agnous.gif

The official world average of tide gauges is extracted in black here, as an inset:

http://s22.postimg.org/ulr1dg7jl/Sea_Level_Two.jpg

Even the global average temperature, if plotted fairly and objectively with a trend line instead of an arbitrary baseline, shows that recent variation has near perfect precedence in the low CO2 era before it, making a mockery of climate model claims that recent warming can only be explained by human influence:

http://oi58.tinypic.com/3rols.jpg

These grade school level basic reality check plots quite simply falsify both hockey stick historical revisionism and climate model claims of attribution, and confirm the hypothesis that negative feedbacks exist in such a vastly complex multi-layered, multi-phase, multiple solar influence, chaotic fluid dynamic system.

Your rhetorical question is vastly oversimplified. By what mechanism would CO2 vary on its own enough to allow the past to become a valid experiment about climate sensitivity to CO2 variation? A massive CO2 asteroid? No such thing! Instead, CO2 was along for the ride as temperature swung about due to many influences such as asteroids, sudden evolutionary developments of industrial capacity microorganisms, and just general fluid dynamic chaos coupled to sun and solar system changes. But today we suddenly *do* have an experiment running and the results are already in, by unnaturally boosting CO2 concentration so suddenly, and finding utterly no trend upswing in the strict linearity of both the oldest real thermometer records and the oldest tide gauge records.

The oldest thermometer records are here, with climate treaty Copenhagen thrown in for laughs:

http://s24.postimg.org/498mmzb6d/2agnous.gif

The official world average of tide gauges is extracted in black here, as an inset:

http://s22.postimg.org/ulr1dg7jl/Sea_Level_Two.jpg

Even the global average temperature, if plotted fairly and objectively with a trend line instead of an arbitrary baseline, shows that recent variation has near perfect precedence in the low CO2 era before it, making a mockery of climate model claims that recent warming can only be explained by human influence:

http://oi58.tinypic.com/3rols.jpg

These grade school level basic reality check plots quite simply falsify both hockey stick historical revisionism and climate model claims of attribution, and confirm the hypothesis that negative feedbacks exist in such a vastly complex multi-layered, multi-phase, multiple solar influence, chaotic fluid dynamic system.

"By what mechanism would CO₂ vary on its own enough to allow the past to become a valid experiment about climate sensitivity to CO₂ variation?"

Before humans, CO₂ was driven primarily by vulcanism and weathering / aqueous mineral sequestration.

Since the industrial revolution, humans have increased CO₂ from 290PPM to 400PPM.

If it's so likely that this level of CO₂ will be compatible with the persistence of polar ice caps, why haven't these things ever been compatible before in Earth's history?

"is there any way to release this account from automatic pre-moderation?"

Not without the author's permission.

If he were telling the truth, why would he need to censor the discussion of his claims?

"The accepted one in the geological world, based on lots of data, all around the world, is this one"

That's GEOCARB III. If you understand this CO₂ proxy has a 30 million year resolution, why would you be attempting to use it to gauge CO₂ during an ice house that lasted less than 2 million years:

"Calculated paleolevels of atmospheric CO2 from the GEOCARB III model, which models the carbon cycle on long time scales (here a 30 million year resolution)."

ftp://ftp.ncdc.noaa.gov/pub/data/paleo/climate_forcing/trace_gases/phanerozoic_co2.txt

Neither Watts nor Geocraft is a reliable source of scientific information. These are dishonest Climate Denier propaganda outlets well-known for lying about climate science.

You may stop linking to them now.