A friend has passed away

July 1, 2014, 11:36 am

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In 1977 he made the movie "the weather machine" about how Earth is doomed to enter a new ice-age. Since those apocalyptic predictions did not materialize, he knew better once the wheels have turned and people talked about imminent warming. That is, his immune system developed immunity against blindly accepting alarmist predictions.

When he learned of my friend Henrik Svensmark's work, he of course found it interesting, which is why several years later they ended up writing a book together, the Chilling Stars.

As for myself, I met him just once. We had lunch in the restaurant opposite to the British Museum, but had plenty of e-mail correspondence. He will be fondly remembered. This is his last blog post.

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Euthanizing Overholt et al.: How bad can a bad paper be?

April 25, 2015, 10:31 pm

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An artists conception of the Milky Way with its spiral arms

Last month I visited the U of Washington to give a talk in which I discussed the effects of cosmic rays on climate. At the end of it, not one, but two people independently asked me about Overholt et al., which supposedly ruled out the idea that passages through the galactic spiral arms affect the appearance of glaciations on Earth (see summary I wrote a few years ago, which includes links to PDFs the actual papers). I told them that the paper had really stupid mistakes and it should be discarded in the waste bin of history, but given that Overholt et al. is still considered at all, I have no choice but to more openly euthanize it.

Before I get into the technical details (which will cause many of the readers to click their way out of here), I do want to say something general about the refereeing process and how it can easily break down, as it did here.

Given that there are many more people who are eager to shoot down the cosmic ray climate link than people researching it, very often I find that the criteria used to accept papers which refute the link are way more lenient than the criteria needed to accept papers that supposedly refute it. This is because the refuters don't have an incentive to find errors in refuting papers (e.g., as I demonstrated with the Shakun et al. paper supposedly finding that CO₂ leads the average global temperature). This is because any paper has a much higher probability of getting refereed by the refuter camp than the proponents camp. Simple statistics.

The second comment is that I wrote them politely, it ended up with an erratum, but to save face they continued claiming the that their paper supports the erroneous claim that my original conclusions are unsubstantiated. One can show that even those leftover criticisms are plagued with errors.

Main Problem

In the their paper, Overholt et al. try to estimate previous passages through the galactic spiral arms, and compare those passages to the appearance of ice-age epochs on Earth, over the past billion years. The gravest error is that the analysis was carried out using a spiral arm pattern speed that was totally different from the range of pattern speed they actually wrote they used!

They wrote that they take 10.1 to 13.7 (km/s)/kpc as the possible range for the relative motion of the spiral arm pattern speed with respect to the solar angular velocity (i.e., a nominal value of about 11.9 (km/s)/kpc). However, if one looks at the average spiral arm crossing as obtained in their analysis, it is about 100 Myr (the first of their group of 4 arm passages is at roughly at 275 Myr and their second group is at roughly 670 Myr). This implies an average spiral arm passage every (670 Myr - 275 Myr)/4 ~ 100 Myr, which is inconsistent with the above pattern speed. In fact, an average spiral arm passage every 100 Myr implies a relative pattern speed of about: $$ \Omega_\odot - \Omega_\mathrm{arm} \approx 15.4 (km/s)/kpc, $$ I am pretty sure that the source of error is the fact that they accidentally took the absolute pattern speed when calculating the spiral arm passages. For their nominal 217 km/s solar velocity at 8 kpc, one gets $\Omega_\odot = 27.1 (km/s)/kpc$, such that the absolute pattern speed obtained for the nominal 11.9 (km/sec)/kpc relative speed, is: $$\Omega_\mathrm{arm} = \Omega_\odot - (\Omega_\odot-\Omega_\mathrm{arm}) = 27.1 − 11.9 = 15.2 (km/s)/kpc$$ i.e., roughly the value I read by eye from their graph describing the spiral arm passages.

Because they accidentally took the absolute pattern speed, they obtained spiral arm crossings which are much more frequent that the climatic data or meteoritic data. If they would have taken the 10.1 to 13.7 range instead, the spiral arm passages would have been 112 to 152 Myr, which includes the ice-age epoch occurrences and the cosmic ray flux variations based on iron meteorites. The phase would have agreed as well.

I then suggested that they publish an erratum to that paper, which they did. However, to save face, they claimed that their re-calculated spiral passages are still inconsistent with the meteoritic data or with the climate record, which brings me to the additional problems still present in their analysis.

Additional Problems

A few more problems relate to the way Overholt et al. derive the spiral arm crossing (which is why even with their erratum, their manuscript is pointless).

First, they take the spiral arm model of Englmaier et al. 2009, but they trace the spiral arms by eye, and as a consequence get a distorted result which gives highly unlikely “tight” clusters of 4 consecutive passages each rotation. In fact, it is so distorted that 2 consecutive arm crossings are of the same arm, which even with the radial epicyclic motion of the solar system is ridiculous.

Second, they assume that their highly asymmetric (and unlikely) spiral arm configuration should remain as such for many spiral arm passages, but because the arms are dynamic, without more information, a more reasonable assumption would have been that the arms would have tended to be separated by 90 degrees instead of the “tight” clusters of 4 consecutive passages.

Third, they didn’t consider the fact that supernovae are biased to take place about 10 to 20 million years after the spiral arm passage because of the finite lifetime of the stars that end their lives as supernova explosions.

Fourth, they don’t actually carry out any statistical analysis how likely or unlikely is it to find all the ice-age epochs as close to the estimated spiral arm passages, not that a statistical analysis would have helped any given their problematic determination of the arm passages.

Last, and perhaps most important. The cosmic ray flux can be shown using Iron meteorites to be periodic with a roughly constant 145 Myr period, and in phase with the appearance of ice-age epochs, which means that any distorted reconstruction such as that of Overholt et al. is inconsistent with the data, which they have totally ignored.

Summary

Overhaul et al. analysis of the spiral arm passages is bad at so many levels it is not really worth ever considering again. However, will people still quote it and claim that it refutes the galactic spiral arm explanation for the appearance of spiral arm passages? Probably, but now you know better.

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Bill Nye, the not-so-good-science guy

June 5, 2015, 10:29 pm

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Bill "the science guy" Nye says that I am a denier.

I recently stumbled on a transcript of Bill “the science guy” Nye’s interview on CNN last week. In it, he said that climate skeptics (i.e., people like myself), are at least as bad as people who deny that smoking causes cancer. There are quite a few things he misses, in fact, he got things totally wrong, but I do like the his analogy to smoking and cancer as you’ll see.

First, what did he actually say? During his appearance on CNN, Bill Nye compared the link between denying a link between climate change and anthropogenic activity to denying a link between smoking and cancer:

“I just want to remind voters that suppose you had somebody running for congressional office in your district who insisted there was no connection between cigarette smoking and cancer. Would you vote for that person? You might, but if this person were adamant — ‘No, the scientists who studied cigarette smoking, they don’t know what…’ — if they were adamant, would you vote for them? And so, in the same way the connection between climate change and human activity is at least as strong as cigarettes and cancer. And so, I just want everybody to keep this in mind: that it’s very reasonable that the floods in Texas, the strengthening storms, especially — the president was in Florida — these things are a result of human activity making things worse. It’s very bad. I get this that people died in Texas, and I am reminding you what else. This is a very expensive business. When you flood the fourth largest city in the United States, somebody is going to pay for it, and it’s you and me. And so, the sooner we get to work on climate change, the better.”

Here’s the actual video:

These short comments and comparison he made are inappropriate for several major reasons.

To begin with, he follows the usual alarmist assertion that every calamity is necessarily due to global warming (now known as “climate change” so that they can cover more ground) and that all the climate change is necessarily anthropogenic. Since bizarre weather patterns can happen all the time with some probability, and since part of the climate change is also natural, these implicit “logical” steps would not make sense, at least in any other scientific discipline. I won’t dwell on this since others already did.

Second, the global warming debate is mostly a quantitative one. While the IPCC claims that climate sensitivity can be very large (e.g., a 4.5°C increase per CO₂ doubling which would be catastrophic), I claim that such high values are ruled as they are inconsistent with a lot of empirical data (e.g., see this). In other words, skeptics like myself don’t argue that CO₂ has no effect on climate, only that the IPCC story is highly exaggerated. On the other hand, whether smoking contributes 90% or 10% of the cases of lung cancer would be good enough reason for any rational person to quit smoking (well, rational and able to overcome his or her addiction). On the other hand, if a given emission scenario over the 21^st century will cause a 1°C or 4°C could make a huge difference. This means that denying that smoking causes cancer is a yes/no question while most skeptics don’t “deny anthropogenic global warming”, instead, they only claim it is minor.

The third point is the main one I want to make. The reasoning behind the attribution of lung cancer to smoke and behind attributing global warming to anthropogenic activity is conceptually different, so different, that putting both on the same pedestal is simply wrong. The evidence linking lung cancer to smoking is in the form highly statistically significant increase in the incidence rate of lung cancer when comparing smoking to non-smoking groups. So, either smoking or something very closely related to it is clearly carcinogenic. The assertion that climate sensitivity is large, that most of the 20^th century warming is necessarily anthropogenic and that temperature increase over the 21^st century will be large are the result of model predictions, not on empirical evidence. In fact, empirical evidence such as the small response to volcanic eruptions (e.g., Lindzen and Giannitsis 1998, see also note on climate effects of volcanoes here), or the lack of correlation between the order of magnitude CO₂ variations over geological time scales and the global temperature (e.g., this discussion on cosmic rays and climate), or of course, the lack of warming over the past nearly two decades, counter to all the model predictions (e.g., see this discussion of the hiatus long before the term was used).

If we use the cancer analogy it would be as if we had a model that can predict, at the biochemical level that some of the chemicals in cigarettes are carcinogenic, and that smoking should cause cancer, but, while the model would say that the incidence rate should be high and should explain most of the lung cancer cases, comparing the actual incidence rate would show that only some modest fraction of the lung cancer cases are attributed to smoking, but the rest are not. Yet, even with the evidence showing only a small difference in the incidence rate between the smoker and non-smoker group, the model will still be believed and it would be used to make predictions to other types of cancers, e.g., saying that they happen at a huge rate while they don’t. Sounds ridiculous? Well, this is what’s happening in climate science.

Anyway, the last time I had any thought about the “science guy”, was when I heard he was to give the commencement speech at my wife’s graduation from Caltech (roughly when the global warming hiatus began!). Back then I thought of how uninspiring it is. I am not saying that publicizing science to the public is not important (which is what Bill Nye did so well), but I didn’t think that this is the kind of figure that will push the young cadet of scientists and engineers into new frontiers. Its isn’t as if he is doing rocket science. In retrospect, I now think it was even less appropriate to have him.

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The Sunspots 2.0? Irrelevant. The Sun, still is.

August 10, 2015, 6:40 am

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cosmic rays, global warming, personal research, weather & climate

After being asked by 5 independent people about the new sunspot number reconstruction and that it doesn’t show that the sun should have contributed any warming to the 20^th century, I decided to write about it here. I have one word to describe it – irrelevant. It is also a good opportunity to write about new results (well, one that saw the light of day a few months ago) showing again that the sun has a large effect on climate. Yet, the world will still continue to ignore it. Am I surprised? No I’m not.

First, what’s the story? A group led by Frédéric Clette had a presentation at the IAU assembly in Hawaii. In it, they argued that the sunspot number suffers from various systematic errors as it is a subjective measurement. Because those systematic errors vary with time (with the different observers and observational methods), the SN reconstruction can exhibit a fictitious long term trend. They also attempted to calibrate the data, and obtain a more homogeneous dataset. This is described at length in their arXiv preprint.

The most interesting aspect about their new sunspot reconstruction is that there is significantly less variation in the sunspot number between the different solar maxima since the Maunder minimum. This implies, according to them, that there wasn't a significant increase in solar activity over the 20^th century (no "20^th century Grand Maximum"), and therefore the sun should not have contributed anything towards increased temperatures. This point was of course captured by the media (e.g., here).

The old and new sunspot number reconstructions

Figure 1: The old (red) and new (blue) sunspot number reconstructions of Clette et al.

So, what do I think about it? First, I have no idea whether the calibration is correct. They do make a good argument that the SN reconstruction is problematic. Namely, some corrections are probably necessary and there is no reason a priori to think that what they did is invalid. However, their claim about solar activity in general not varying much since the sun came out from the Mounder minimum is wrong. There are other more objective ways to reconstruct solar activity than subjective sunspot counting, and they do show us that solar activity increased over the 20^th century. So at most, one can claim that solar activity has various facets, and that the maximum sunspot number is not a good indicator of all of them. This is not unreasonable since the number of sunspots would more directly reflect the amount of closed magnetic field lines, but not the open ones blowing in the solar wind.

The two important objective proxies for solar activity are cosmogenic isotopes (¹⁴C and ¹⁰Be), and the geomagnetic AA index. The AA index (measured since the middle of the 19^th century) clearly shows that the latter part of the 20^th century was more active than the latter half of the 19th century. The longer ¹⁰Be data set reveals that the latter half of the 20^th century was more active than any preceding time since the Maunder minimum. (The ¹⁴C is a bit problematic because human nuclear bombs from the 1940's onwards generated a lot of atmospheric ¹⁴C so it cannot be used to reconstruct solar activity in the latter part of the 20^th century).

The Geomagnetic AA index showing an increase in solar activity

Figure 2: The AA geomagnetic index showing a clear increase in solar activity over the 20^th century (From here).

The Beryllium 10 decrease from solar activity increase

Figure 3: The ¹⁰Be production showing again, that the sun was particularly active in the latter half of the 20^th century. The sunspot number is the "old" reconstructions without Clette's et al. corrections.

What does it tell us? Given that long term variations in Earth's climate do correlate with long term solar activity (e.g., see the first part of this) and given that some solar activity indicators (presumably?) don't show an increase from the Maunder minimum, but some do, it means that climate is sensitivite to those aspects of the solar activity that increased (e.g., solar wind), but not those more directly associated with the number of sunspots (e.g., UV or total solar irradiance). Thus, this result on the sunspots maxima (again, if true), only strengthens the idea that the solar climate link is through something related to the open magnetic field lines, such as the strength of the solar wind or the cosmic ray flux which it modulates.

The second point I wanted to write about is a recently published analysis showing that the sun has a large effect on climate, and quantifying it. In an earlier work, I showed that you can use the oceans as a calorimeter to see that the solar radiative forcing over the solar cycle is very large, by looking at various oceanic data sets (heat content, sea surface temperature and tide gauges). How large? About 6-7 times large than one can naively expect from changes in the solar irradiance.

More recently, Daniel Howard, Henrik Svesmark and I looked at the satellite altimetry data. It is similar to the tide gauge records in that it measures how much heat goes into the ocean by measuring the sea level change (most of the sea level on short time scales is due to thermal expansion). Unsurprisingly, we found that the satellite altimetry showed the same solar-cycle synchronized sea level change as the tide gauge records. However, because the satellite data is of such high quality, it is has a higher temporal resolution than the tide gauge records which allows singling out the thermal expansion component from other terms (e.g., associated with trapping of water on land). This allows for an even better estimate of the solar forcing, which is 1.33±0.34 W/m² over the last solar cycle. You can see in fig. 4 how much the sun and el-Niño can explain a large fraction of the sea level change over yearly to decadal time scales.

Altimetry based sea level data showing the solar influence

Figure 4: Sea level data and the model fit. The blue dots are the linearly detrended global sea level measured with satellite altimetry. The purple line is the model fit to the data which includes both a harmonic solar component and an ENSO contribution. The shaded regions denote the one sigma and 1% to 99% confidence regions. The fit explains 71% of the observed variance in the filtered detrended data.

The bottom line is that the sun appears to have a large effect on the climate on various time scales. Whether or not the sunspots reflect the increase in solar activity since the Maunder minimum (as reflected in other datasets) is not very important. At most, if they don't reflect, it only strengthen's the idea that something associated with the solar wind does (such as the cosmic rays which they modulate).

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Climate debate at the Cambridge Union - a 10 minute summary of the main problems with the standard alarmist polemic

November 2, 2017, 2:35 pm

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Last week I participated in an interesting debate that was held at the Cambridge Union, the oldest debating club in the world (dating back to 1815. The invite was to be on the side opposing the proposition “This house would rather cool the planet than warm the economy”.

Although I think the phrasing of the question is problematic to begin with, since it assumes that “warming the economy” necessary would cool the climate, I should applaud the Cambridge Union for supporting free speech and allowing people on both side to voice their arguments, especially given how many on the alarmist side refuse to do so, claiming that there is nothing to debate anymore.

I should also add that I was quite shocked to see how the audience was so one sided (though far less than the ridiculous 97:3 ratio we hear about!) and unwilling to listen to scientific arguments. I am actually quite lucky to be living in Israel where free speech and free thought are really more than lip service. Having honest debates in Israeli academia or in the media is actually the norm.

Below you will find the summary I wrote myself before the debate. Since it is rather concise I thought it would be a good idea to bring it here as well.

Have fun

— Nir

Let me begin by asking you a question. What is the evidence that people, like the proponents here, use to prove that we humans are responsible for global warming and that future warming will be catastrophic if we don’t get our act together?

The fact is that this idea is a misconception and the so called evidence we constantly hear is simply based on fallacious arguments.

To begin with, any one who appeals to authority or to a majority to substantiate his or her claim is proving nothing. Science is not a democracy and the fact that many believe one thing does not make them right. If people have good arguments to convince you, let them use the scientific arguments, not logical fallacies. Repeating it ad nauseam does not make it right!

Other irrelevant arguments may appear scientific, but they are not. Evidence for warming is not evidence for warming byhumans. Seeing a poor polar bear floating on an iceberg does not mean that humans caused warming. (Actually, the bear population is now probably at its highest in modern times!). The same goes to receding glaciers. Sure, there was warming and glaciers are receding, but the logical leap that this warming is because of humans is simply an unsubstantiated claim, even more so when considering that you can find Roman remains under receded glaciers in the Alps or Viking graves in thawed permafrost in Greenland.

Other fallacious arguments include using qualitative arguments and the appeal to gut feelings. The fact that humanity is approaching 10 billion people does not prove that we caused a 0.8°C temperature increase. We could have just as much caused an 8°C increase or an 0.08°C. If all of humanity spits into the ocean, will sea level rise appreciably?

In fact, there is no single piece of evidence that proves that a given amount of CO2 increase should cause a large increase in temperature. You may say, “just a second, we saw Al Gore’s movie, in which he presented a clear correlation between CO2 and temperature from Antarctic ice cores”. Well, what he didn’t tell you is that one generally sees in the ice cores that CO2 lags the temperature by typically a few hundred years, not vice versa! The simple truth is that Al Gore simply showed us how the amount of CO2 dissolved as carbonic acid in the oceans changes with temperature. As a matter of fact, over geological time scales, there were huge variations in the CO2 (a factor of 10) and they have no correlation whatsoever with the temperature. 450 million years ago there was 10 times as much CO2 in the atmosphere but more extensive glaciations.

When you throw away the chaff of all the fallacious arguments and try to distill the climate science advocated by the IPCC and alike, you find that there are actually two arguments which appear as legitimate scientific arguments, but unfortunately don’t hold water. Actually, fortunately! The first is that the warming over the 20th century is unprecedented, and if so, it must be human. This is the whole point of the hockey so extensively featured in the third assessment report of the IPCC in 2001. However if you would google “climategate” you would find that this is a result of shady scientific analysis - the tree ring data showing that there was little temperature variation over the past millennium showed a decline after 1960, so, they cut it off and stitched thermometer data. The simple truth is that in the height of the middle ages it was probably just as warm as the latter half of the 20th century. You can even see it directly with temperature measurements in boreholes.

The second argument is that there is nothing else to explain the warming, and if there is nothing else it must be the only thing that can, which is the anthropogenic contribution. However, as I mention below, there is something as clear as daylight… and that is the sun.

Before explaining why the sun completely overturns the way we should see global warming and climate change in general. It is worth while to say a few words on climate sensitivity and why it is impossible to predict ab initio the anthropogenic contribution.

The most important question in climate science is climate sensitivity, by how much will the average global temperature increase if you say double the amount of CO2. Oddly enough, the range quoted by the IPCC, which is 1.5 to 4.5°C per CO2 doubling was set, are you ready for this, in a federal committee in 1979! (Google the Charney report). All the IPCC scientific reports from 1990 to 2013 state that the range is the same. The only exception is the penultimate report which stated it is 2 to 4.5. The reason they returned to the 1.5 to 4.5 range is because there was virtually no global warming since 2000 (the so called “hiatus”), which is embarrassingly inconsistent with a large climate sensitivity. What’s more embarrassing is that over almost 4 decades of research and billions of dollars (and pounds) invested in climate research we don’t know the answer to the most important question any better? This is simply amazing I think.

The body of evidence however clearly shows that the climate sensitivity is on the low side, about 1 to 1.5 degree increase per CO2 doubling. People in the climate community are scratching their heads trying to understand the so called hiatus in the warming. Where is the heat hiding? While in reality it simply points to a low sensitivity. The “missing” heat has actually escaped Earth already! If you look at the average global response to large volcanic eruptions, from Krakatoa to Pinatubo, you would see that the global temperature decreased by only about 0.1°C while the hypersensitive climate models give 0.3 to 0.5°C, not seen in reality. Over geological time scales, the lack of correlation between CO2 and temperature places a clear upper limit of a 1.5°C per CO2 doubling sensitivity. Last, once we take the solar contribution into account, a much more consistent picture for the 20th century climate changes arises, one in which the climate drivers (humans AND solar) are notably larger, and the sensitivity notably smaller.

So, how do we know that the sun has a large effect on climate? If you search on google images “oceans as a calorimeter”, you would find one of the most important graphs to the understanding of climate change which is simply ignored by the IPCC and alarmists. You can see that over more than 80 years of tide gauge records there is an extremely clear correlation between solar activity and sea level rise - active sun, the oceans rise. Inactive sun - the oceans fall. On short time scales it is predominantly heat going to the oceans and thermal expansion of the water. This can then be used to quantify the radiative forcing of the sun, and see that it is about 10 times larger than what the IPCC is willing to admit is there. They only take into account changes in the irradiance, while this (and other such data) unequivocally demonstrate that there is an amplifying mechanism linking solar activity and climate.

The details of this mechanism are extremely interesting. I can tell you that it is related to the ions in the atmosphere which are governed by solar activity and in fact, there are three microphysical mechanisms linking these ions to the nucleation and growth of cloud condensation nuclei. Basically, when the sun is more active, we have less clouds that are generally less white.

So, the main conclusion is that climate is not sensitive to changes in the radiative forcing.

This means that we are not required to “cool the economy” in order to cool earth. In Paris and Copenhagen the leaders of the world said that we should make sure that the total global warming will be less than 2°C. It will be less than 2°C even if we do nothing. There are several red flags that people do their best to ignore. The lack of warming in the past 2 decades is a clear sign that sensitivity is low, but people ignore it.

Last point. People say that we should at least curb the emissions as a precautionary step. However, resources are not infinite. Most people in developed nations can pay twice for their energy, but for third world nations? It would mean more expensive food, hunger and poverty, and many in the developed world actually freezing in winter. So in fact, taking unnecessary precautionary steps when we know they are unnecessary is immoral. It is even committing statistical murder.

Now the really last point, I am also optimist that humanity will switch to alternative energy sources in less than 2-3 decades just because they will become cheap enough, and just for the reason that people want to save money. Just like the price of computers has plummeted exponentially (Moore’s law— number of transistors doubles every 18 months) so does the cost of energy from photovoltaic cells (cost halves every 10 years). Once they will be really cost effective, without subsidies, suddenly we won’t be burning fossil fuels because it would be the expensive thing to do!

Let us use our limited resources to treat real problems.

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Finally! The missing link between exploding stars, clouds and climate on Earth

December 19, 2017, 4:30 am

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astronomy, cosmic rays, global warming, personal research, weather & climate

By Henrik Svensmark and Nir shaviv

Our new results published today innature communications provide the last piece of a long studied puzzle. We finally found the actual physical mechanism linking between atmospheric ionization and the formation of cloud condensation nuclei. Thus, we now understand the complete physical picture linking solar activity and our galactic environment (which govern the flux of cosmic rays ionizing the atmosphere) to climate here on Earth though changes in the cloud characteristics. In short, as small aerosols grow to become cloud condensation nuclei, they grow faster under higher background ionization rates. Consequently, they have a higher chance of surviving the growth without being eaten by larger aerosols. This effect was calculated theoretically and measured in a specially designed experiment conducted at the Danish Space Research Institute at the Danish Technical University, together with our colleagues Martin Andreas Bødker Enghoff and Jacob Svensmark.

Background:

It has long been known that solar variations appear to have a large effect on climate. This was alreadysuggested by William Herschel over 200 years ago. Over the past several decades, more empirical evidence have unequivocally demonstrated the existence of such a link, as exemplified in the examples in the box below.

Box 1: Examples demonstrating the Solar/Climate link

Below are several examples showing that the sun has a large effect on climate. The first example is the beautiful correlation between solar activity (as mirrored in theCarbon 14 extracted from tree rings) and Oxygen 18 to Oxygen 16 isotope ratio is stalagmites in a cave in Oman, measured byNeff et al. (2001). The former is a proxy of solar activity (as the solar wind modulates the flux of cosmic rays reaching the terrestrial atmosphere and producing Carbon 14 through spallation).Oxygen 18 is a well known climate proxy (in this case, of the monsoon rain coming from the Indian ocean).

Figure 1: A correlation between ¹⁴C/¹²C from tree rings (a proxy of solar activity) and ¹⁸O/¹⁶O from stalagmites in a cave in Oman in the southern Arabian peninsula by Neff et al. (2001) (which is a proxy of the temperature of the Indian ocean). A large correlation is apparent.

The second example, by Bond et al. (2001), shows a clear correlation between solar activity (again as recovered using ¹⁴C) and the climate of the North Atlantic, as can be reconstructed from ice rafted debris in cores from the ocean floor.

Figure 2: A correlation between ¹⁴C/¹²C from tree rings (a proxy of solar activity) and the amount of ice rafted debris left on the ocean floor in the Northern Atlantic. Again, a large correlation is apparent.

The third example, on shorter time scales, is the clear correlation between solar activity over the past century, exhibiting the quasi periodic 11 year solar cycle, and the rate of change of the sea level.

Figure 3: The correlation between solar activity (in red) and the sea level rate of change from tide gauges across the globe.

Unlike the previous results which qualitatively demonstrate the existence of a strong solar/climate link, the last correlation, byShaviv (2008), can be used to quantify the link and show that the solar minimum to solar maximum variations in the solar activity translates into a 1 to 1.5 W/m² change in Earth’s energy budget. A more recent analysis of satellite altimetry data reveals that the correlation continues. In fact, if one removes the linear trend from glacier melting, almost all the sea level change can be attributed to the sun and the el Niño southern oscillation (Howard et al. 2015).

Figure 4: The correlation between the linearly detrended sea level measured using satellite altimetry (blue dots) and a model fit which includes just two components: The sun and el Niño southern oscillation. The excellent fit implies that the two components are by far the dominant source of sea level change on short time scales.

The fact that the ocean sea level changes with solar activity (see Box 1 above) clearly demonstrates that there is a link between solar activity climate, but it can be used to quantify the solar climate link and show that it is very large. In fact, this “calorimetric” measurement of the solar radiative forcing is about 1 to 1.5 W/m² over the solar cycle, compared with the 0.1-0.2 W/m² change expected from just changes in the solar irradiance. This means that a mechanism amplifying solar activity should be operating—the sun has a much larger effect on climate than can be naively expected from just changes in the solar output.

Over the years, a couple of mechanisms were suggested to explain the large solar climate link. However, one particular mechanism has accumulated a significant amount of evidence in its support. The mechanism is that of solar wind modulation of the cosmic rays, which govern the amount of atmospheric ionization, and which in turn affect the formation of cloud condensation nuclei and therefore how much light do the clouds reflect back to space, as we now explain.

Cosmic Rays are high energy particles originating from supernova remnants. These particles diffuse through the Milky Way. When they reach the solar system they can diffuse into the inner parts (where Earth is) but lose some energy along the way as they interact with the solar wind. Here on Earth they are responsible for most of the ionization in the Troposphere (the lower 10-20 km of the atmosphere where most of the “weather” takes place). We now know that this ionization plays a role in the formation of cloud condensation nuclei (CCNs). The latter are small (typically 50nm or larger) aerosols upon which water vapor can condense when saturation (i.e., 100% humidity) is reached in the atmosphere. Since the properties of clouds, such as their lifetime and reflectivity, depends on the number of CCNs, changing the CCNs formation rate will impact Earth’s energy balance.

The full link is therefore as follows: A more active sun implies a lower CR flux reaching Earth and with it, lower ionization. This in turn implies that fewer cloud condensation nuclei are produced such that the clouds that later form live shorter lives and are less white, thereby allowing more solar radiation to pass through and warm our planet.

Figure 5: The link between solar activity and climate: A more active sun reduces the amount of cosmic rays coming from supernovae around us in the galaxy. The cosmic rays are the dominant source of atmospheric ionization. It turns out that these ions play an important role in (a) increasing the nucleation of small condensation nuclei (a few nm) and (b) increasing the growth rate of the condensation nuclei (which is the effect just published). The larger growth rates imply that they are less likely to stick to pre-existing aerosols and thus have a larger chance of reaching the sizes of cloud condensation nuclei (CCNs, typically > 50 nm in diameter). Thus, a more active sun decreases the formation of CCNs, making the clouds less white, reflecting less sunlight and therefore warming Earth.

Until today we had just empirical results which demonstrate that this link is indeed taking place. The main results are summarized in Box 2 below. In particular, we have seen correlations between solar activity and cloud cover variations, as well as between cosmic ray flux variations arising from changes in our galactic environment and long term climate change using geological data.

Box 2: Examples showing the cosmic ray climate link

The first empirical evidence linking solar activity with cloud cover was the correlation between solar activity (as proxied by the cosmic rays) and changing cloud cover (Svensmark & Friis-Christensen 1997), in particular, the low altitude cloud cover (seeMarsh & Svensmark 2000). Although later data has cross-satellite calibration problems, the correlation continued. Interestingly, Cosmic rays exhibit an odd/even asymmetry because they are the only solar modulated component that “sees” the fact that subsequent solar cycles have opposite magnetic field polarity. The cloud cover appears to exhibit the same asymmetry.

Figure 6: The correlation between low altitude cloud cover (blue) and the cosmic ray flux reaching earth (red).

Later, more evidence for the fact that cosmic rays are not only the proxy of solar activity but are an actual part of the climate mechanism appeared in the form of correlations between cosmic ray flux variations that have nothing to do with solar activity and climate variations. Such variations in the cosmic ray flux exit over geological time scales. We showed that one can use Iron meteorites to reconstruct the cosmic ray flux variations over the past billion years. These variations exhibit seven increases due to passages through the galactic spiral arms, on one hand, but appear to correlate with the appearance of ice age epochs on Earth, on the other (Shaviv, 2002, Shaviv 2003, Shaviv & Veizer 2003). Clearly, cosmic ray flux variations that are independent of solar activity appear to have a large effect on climate as well.

The first suggestion for an actual physical mechanism was that ions increase the nucleation of small (2-3 nm sized) aerosols called condensation nuclei (CNs). The idea is that small clusters of sulfuric acid and water (the main building blocks of small aerosols) are much more stable if they are charged. That is, the charge allows the aerosols to grow from a very small (few molecule) cluster to a small stable CN without breaking apart in the process. This effect was first seen in our lab (Svensmark 2006). The effect was seen again in the CLOUD experiment running at CERN (Kirkby 2011). Later experiments have shown that ions accelerate also other nucleation routes in which the small clusters are stabilized by a third molecule (such as Ammonia). That is, ions play a dominant role in accelerating almost all nucleation routes (as long as the total nucleation rate is lower than the ion formation rate).

Figure 7: The Ion induced nucleation effect measured in the lab. Left: The first demonstration in our SKY experiment showing that increased ionization increases the nucleation of small aerosols (typically 3 nm in size). Right: Corroboration of the results in the CLOUD experiment at CERN.

In the meantime, a number of research groups aimed at testing the idea that cosmic ray ionization could help the formation of cloud condensation nuclei (CCN). This was done by using large global circulation models coupled with aerosol physics. The idea was to see if an added number of small aerosols would grow into more CCNs. All of the numerical models gave the result that the small aerosols were lost before they could become large enough, leading to the conclusion that the effect of cosmic rays on the number of CCN over a solar cycle was insignificant (e.g., Pirece and Adams 2009). This could also be explained analytically (Smith et al. 2016). It was therefore proclaimed that the theory was dead.

Given the empirical evidence, it was clear to us that a link must be present, even if the ion induced nucleation mechanism itself is insufficient to explain the link. Thus, our response was to address the same question without using models but instead to test it experimentally. Therefore, in 2012 we tested if small nucleated aerosols could grow into CCN in our laboratory and discovered that without ions present, the response to increased nucleation was severely damped, just like the above-mentioned models; however with ions present, all the extra nucleated particles grew to CCN sizes, in contrast to the numerical model results (Svensmark et al. 2013). So, experiments contradicted the models. The logical conclusion was that some unknown ion-mechanism is operating, helping the growth.

Figure 8: Left: When injecting small aerosols, the relative increase decreases with aerosol size because as aerosols grow they tend to coagulate with larger aerosols. Right: However, when increasing the ionization in the chamber, not only are more aerosols nucleated, the relative increase survives to larger sizes implying that some mechanism is increasing the survivability of the aerosols as they grow.

Following the experimental results showing that increased ionization does indeed increase the number of large CCNs, the natural question to ask was whether these results were caused by the particular experimental conditions—perhaps this mechanism does not work in the real atmosphere. It is therefore fortunate that our Sun carries out natural experiments with the whole Earth.

On rare occasions, “explosions” on the Sun called coronal mass ejections result in a plasma cloud passing the Earth, with the effect that the cosmic rays flux decreases suddenly and remains low for about a week. Such events, with a significant reduction in the cosmic ray flux, are called Forbush decreases, and are ideal to test the link between cosmic rays and clouds. Finding the strongest Forbush decreases and using three independent cloud satellite datasets and one dataset for aerosols, we clearly found a response to Forbush decreases. These results validated the whole chain from solar activity, to cosmic rays, to aerosols (CCN), and finally to clouds, in Earth’s atmosphere (Svensmark et al 2009, Svensmark et al. 2016).

Figure 9: The average effect of the 5 strongest Forbush decreases in the 1987-2007 period on cloud properties. Plotted in red is the reduction in the cosmic ray flux following “gusts” in the solar wind (from Coronal Mass Ejections). In black we see the reduction in aerosols over the oceans and three different cloud parameters from three different datasets (Svensmark et al 2009). These results provide an in situ demonstration of the effect of cosmic rays on aerosols and cloud properties.

With the accumulating empirical and experimental evidence, it was clear that atmospheric ionization is playing a role in the generation of the aerosols needed for cloud formation, however, the exact mechanism proved to be elusive. For this reason, we decided to setup another laboratory experiment mimicking conditions found in the real atmosphere and study how atmospheric ions may be affecting the production of CCNs. This also led us to look for alternative mechanisms which will increase the survivability of the CNs as they growth. Indeed, after several years of research, one was found.

The discovery

A little more than 2 years ago, we made the realization that charge will play a role in accelerating the growth rate of small aerosols. When more ions are present in the atmosphere, more of them end up sitting on sulfuric acid clusters of a few molecules. Moreover, the charge makes the sulfuric acid clusters stick to the growing aerosols much faster, as we explain in the box below. Since faster growing aerosols have lower chances of coagulating with larger aerosols, more of the growing aerosols can then survive to reach larger sizes. In other words, when the ionization rate is higher, more CCNs can are formed.

Box 3: The physics behind the new mechanism

The physics responsible for the accelerated growth is actually relatively simple. A charged cluster of a few molecules of sulfuric acid and water will induce a polarization on the growing aerosols—charge will move from one side of the aerosol to the other, such that one side will be positively charged, while the other negatively charged (with no net charging of the aerosols). Through interaction with this polarization (called Debye force), the cluster and aerosols are attracted. This means that charged clusters stick onto the aerosols notably faster than neutral clusters. Thus, when more ions are present, aerosols can grow faster, and if so, the probability that they stick onto larger aerosols (and thus lost from the system) is smaller.

Figure 10: A negatively charged cluster induces a polarization of the neutral aerosol and then gets attracted to it (since the pull from the positive side of the aerosol is stronger than the push from the negative side).

After realizing that this effect should be taking place we did two things. First, we calculated how large it should be and found that for the typical conditions present in the pristine air above oceans, in which the typical sulfuric acid density is a few 10⁶ molecules/cm³, the ions accelerate the growth by typically 1 to 4%. However, because the number of aerosols surviving the growth is exponentially small (typically several e-folds), the relative change in the CCN density is a few times larger still (by the number of e-folds in the exponential damping to be precise). Thus, over the solar cycle (which changes the tropospheric ionization by typically 20%), we expect a several percent variation in the CCN density and with it, the cloud properties, as is observed.

The second thing we did was go to the lab and design an experiment in which we can see this effect taking place (and also validate our theoretical calculations). This is not trivial because the effect is larger for lower sulfuric acid levels (as a larger percentage of the molecules would be charged). However we cannot measure at very low sulfuric acid levels because the aerosols then grow very slowly such that they stick to the chamber walls before their growth can be reliably measured. This forced us to measure at high sulfuric acid levels for which the effect is smaller. This posed a formidable technological challenge. To overcome this, we designed an experiment which can keep relatively stable conditions over long periods (up to several weeks at a time) during which we could automatically increase or decrease the ionization rate at the chamber. This allowed us to collect a large amount of data and get high quality signals (e.g., see fig. 11 in the box below).

We found that aerosols indeed grow faster when the ionization rate is higher, totally consistent with the theoretical predictions (as can be seen in fig. 12 in the box below). This allows them to survive the growth period without coagulating with larger aerosols.

Box 4: Sample Results

Although the reader is can read the article online, here are a few sample results.

Figure 11: The growth of aerosols in the experiment. Lower panel: Color coded is the number density of aerosols as a function of time (horizontal axis), and diameter of aerosols in nm (vertical axis). Every 2 hours the γ-ray sources are opened/closed. Thus, part of the growth is with high ionization and part with low such that the growth rates can be compared. Top: Since the differences are not large under the experimental conditions, the ionizing sources can be switched on/off over many cycles to get high quality statistics. The reason that the signal is small in the experiment is because growth in the chamber has to be an order of magnitude faster than in the atmosphere, otherwise the aerosols would stick to the chamber walls. Under the faster growth conditions, the effect is smaller.

Figure 12: Difference in the γ-ray open and closed growth times (from 6 to 12 nm), in 11 runs with different sulfuric acid densities (and therefore growth rates) and different change in ionization. The dashed lines are the theoretical predictions.

So, what do the results imply? Until now we had significant amount of empirical evidence which demonstrated that cosmic rays affect climate, but we didn't have the actual underlying physical mechanism pinned down. Now we have. It means that we not only see the existence of a link, we now understand it. Thus, if the solar activity climate link was until now ignored under the pretext that it cannot be real, this will have to change. But perhaps more interestingly, it also explains how long term variations in our galactic environment end up affecting our climate over geological time scales.

Box 5: Why is the CR/climate link ignored?

Given all the empirical evidence that has accumulated until now, the climate community should have considered it seriously, and even if the actual mechanism was until now missing, the empirical evidence showing and quantifying the solar climate link shouldn’t have been ignored by most of the community.

The reason is actually very simple and lays in the implication of the link. If the sun has a large effect on climate, then its increase activity over the 20^th century should have contributed at least some of the global warming. In fact, the calorimetric sea level based measurements imply that a bit more than half of the 20^th century warming should be attributed to the sun. If so, the role that humans have had is diminished. In fact, when one considers the role that the sun has had over the 20^thcentury, one finds that a) the temperature variations can actually be much better explained (with a smaller residual) and the required climate sensitivity is on the low side (about 1 to 1.5°C increase per CO₂ doubling, compared with the canonical range of 1.5 to 4.5°C advocated by the IPCC, see Ziskin & Shaviv, 2012). The low climate sensitivity implies that the same emission scenarios will give rise to more modest temperature increases over the 21^st century. These good news imply that we are not in as dire a situations as we often hear. But many do not like hearing this.

Now that the mechanism is actually known, there should be no excuse in ignoring it any further, but given the above implications, it would most likely still be ignored.

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Climate debate at the Cambridge Union - The Video

January 6, 2018, 9:22 am

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Blog topic:

general science, global warming, personal research, politics, weather & climate

Two months ago I wrote about the Cambridge Union Debate I participated in. The Cambridge Union has meanwhile posted the debate online. Here is my part of it. (It starts at 32m31s.)

I should add that the debate was a real eye opener. By living in Israel, I have had the luxury of experiencing a mostly diverse society, open to a wide range of scientific (and other) opinions. This has allowed me to carry out research without having to care about what other people think. It stands however in stark contrast to the body of Cambridge students I addressed. They are well intentioned but unfortunately completely brainwashed. They cite the 97% polemic about most scientists believing in anthropogenic global warming without stopping for a second to think about it, or the evidence that supposedly supports it. They want to think of themselves as liberals, but in fact, they have the most conservative mindset unable to even attempt objective thinking.

The only exception, which stood out as remarkable contrast to the rest, was the remark made by a historian named Josh from Christ college (at 1h 21m 21s).

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My experience at the German Bundestag's Environment Committee in a pre-COP24 discussion

December 7, 2018, 6:17 am

≫ Next: 22 minute talk summarizing my views on global warming

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Blog topic:

general science, global warming, politics, weather & climate

Last week I had the opportunity to talk in front of the Environment committee of the German Bundestag. It was quite an interesting experience, and frankly, something I would have considered unlikely before receiving the invitation. It was in fact the first time a climate "skeptic" like myself appeared behind those doors in many years.

As I understand, the committee was used to inviting Prof. Schellnhuber, formerly the director of the Potsdam Institute for Climate Impact Research. However, as he recently retired, there were voices that the committee should freshen up and invite someone else, and the name that came up was that of Prof. Anders Levermann, also from the same PIK. That however triggered some of the parties to request other people as well, and the committee ended up inviting 6 specialists. Two were bona fide scientists (including myself and Levermann) while the four other were experts on other topics. My name popped up by the right wing AfD party who's climate agenda is consistent with my climate findings—that global warming is a highly exaggerated scare.

The earliest flight from Israel that day would have brought me to the Bundestag awfully close to the beginning of the discussion. So I flew in the day before. I landed in a freezing cold Berlin (-3°C) but sunny! Actually exhilarating weather I quite like.

The next day I showed up at the committee. I was interviewed by someone form a local news outlet that I was told has the tendency to distort the interviews with people like myself (if anyone knows about it, I'm curious, so leave a comment about it if you have seen it).

As I entered the committee room and sat down, Levermann past by and told me in hebrew, אתה יודע שאתה טועה (You know that you're wrong). Which of course caught me in a bit of surprise. It turns out that Levermann did his PhD with Prof. Itamar Procaccia at the Weizmann institute, a world expert in turbulence, nonlinear phenomena and statistical mechanics. Anyway, my German can be described as somewhere between nonexistent and really awful (I studied for a year when I was in high school in the US but forgot most), but enough to say, Ich glaube ich bin recht (I believe I am right).

The discussion started with each one of the experts allowed to talk for 3 minutes. It is actually quite a problem. People have been brain washed to think about global warming as mostly anthropogenic and almost unavoidably catastrophic. How do you prove to people that they are all wrong (or more precisely, that they were told highly exaggerated tales) in such a short time? To make things worse, I was told at the last minute that their TV is broken. Thus, the powerpoint slides I prepared were actually printed out and given to the committee members.

Given that, I had I think no choice but to concentrate on what I think is the biggest error you find in the IPCC, and which clearly overturns the standard polemic, and that is that the sun has a large effect on climate.

Here is what I prepared (what I said was pretty close but not all verbatim):

Three minutes is not a lot of time, so let me be brief. I’ll start with something that might shock you. There is no evidence that CO2 has a large effect on climate. The two arguments used by the IPCC to so called “prove” that humans are the main cause of global warming, and which implies that climate sensitivity is high, are that: a) 20th century warming is unprecedented, and b) there is nothing else to explain the warming.

These arguments are faulty. Why you ask?

We know from the climate-gate e-mails that the hockey stick was an example of shady science. The medieval warm period and little ice ages were in fact global and real. And, although the IPCC will not admit so, we know that the sun has a large effect on climate, and on the 20th century warming in particular.
In the first slide we see one of the most important graphs that the IPCC is simply ignoring. Published already in 2008, you can see a very clear correlation between sea level change rate from tide gauges, and solar activity. This proves beyond any doubt that the sun has a large effect on climate. But it is ignored.

To see what it implies, we should look at figure 2.
This is the contribution to the radiative forcing from different components, as summarized in the IPCC AR5. As you can see, it is claimed that the solar contribution is minute (tiny gray bar). In reality, we can use the oceans to quantify the solar forcing, and see that it was probably larger than the CO2 contribution (large light brown bar).

Any attempt to explain the 20th century warming should therefore include this large forcing. When doing so, one finds that the sun contributed more than half of the warming, and climate has to be relatively insensitive. How much? Only 1 to 1.5°C per CO2 doubling, as opposed to the IPCC range of 1.5 to 4.5. This implies that without doing anything special, future warming will be around another 1 degree over the 21st century, meeting the Copenhagen and Paris goals.

The fact that the temperature over the past 20 years has risen significantly less than IPCC models, should raise a red flag that something is wrong with the standard picture.

I should also add that science is not a democracy. The majority is not necessarily right! You should also be careful and make the distinction between evidence for warming and evidence for warming by humans. There is in fact no evidence for the latter. Last, people may frighten you with secondary climate effects associated with global warming, on the sea level, cryosphere, droughts floods or economic effects. However, if the underlying climate model is fundamentally wrong, all the ensuing predictions are irrelevant.

The fear of global warming, and with it the denouncement of any other voice, is now part of our Zeitgeist. However instead of blindly flowing with the flow, we should stop for a minute and think before we waste so much of our precious public resources. Maybe we will find out the that the emperor has new clothes.

When invited, I was also told that I can submit a written statement, which is what I did. It is a few times longer and has a bit more information. You can find it on the Bundestag's website, with a German translation.

Then came the questions, which were mostly guiding questions - each party asked the expert close to its heart to basically continue saying whatever they wanted to hear. One of the questions I was asked was about the determination of the global temperature, but frankly I didn't understand it. I should add that I had to rely on simultaneous translatation (there were two translators brought in especially for me, I think), and the translated question I heard in English sounded like somethig a bit convoluted and hard to address.

Anyway, during the whole discussion I was directly criticized by Levermann and by Lorenz Beutin, MdB (Bundestag member from Die Linke - the "The Left").

The first such critique was prompted by a request to Levermann, to address why I was wrong in my speech. I should say that Levermann seems nice at the personal level. I have nothing against him, but I his response at this round was totally unscientific. He said that everything I said is rubbish (at least that was the English translation I heard), which of course is not a scientific argument.

The second round came from Beutin. He actually raised two interesting specific points which Levermann pickup on as well, which is great, because this is what science is all about. Argue about specific scientific facts and the conclusions that can be drawn from them.

So what were the points that were raised by Beutin and Levermann?

1) The average sea level change rate (in the solar / sea level change rate graph) is above zero, proving that there was long term sea level rise.

2) From about 1990, solar activity has decreased but the temperature increased. So the sun cannot cause the warming.

3) It is all just correlations (and therefore proving nothing).

Why are these arguments either irrelevant or wrong?

1) Indeed as Beutin noted, the average of the sea level rise is above zero. This is of course true. I should say that I am actually really happy that a politician takes notice of such a subtle point. Sea level has increased over the 20th century (because of warming, melting, and glacial rebound), but the sea level rise is not the signal I am looking at. It is an interesting consequence of the global warming. However, I am looking for the drivers of the warming, not the consequences at this point! And the fact that sea level is rising does not contradict the fact that you see the sun’s 11-year signature clearly, with which you can quantify the solar radiative forcing. Clearly then, this argument is irrelevant. The logical leap from a rising sea level to the fact that the sun is not a major climate driver is baseless.

2) Rising temperatures with falling solar activity from the 1990's. The argument here is of course that the negative correlation over this period tells us that the sun cannot be the major climate driver. This too is wrong.

First, even if the sun was the only climate driver (which I never said is the case), this anti-correlation would not have contradicted it. Following this simple logic, we could have ruled out that the sun is warming us during the day because between noon and say 2pm, when it is typically warmest, the amount of solar radiation decreases while the temperature increases. Similarly, one could rule out the sun as our source of warmth because maximum radiation is obtained in June while July and August are typically warmer. Over the period of a month or more, solar radiation decreases but the temperature increases! The reason behind this behavior is of course the finite heat capacity of the climate system. If you heat the system for a given duration, it takes time for the system to reach equilibrium. If the heating starts to decrease while the temperature is still below equilibrium, then the temperature will continue rising as the forcing starts to decrease. Interestingly, since the late 1990’s (specifically the 1997 el Niño) the temperature has been increasing at a rate much lower than predicted by the models appearing in the IPCC reports (the so called “global warming hiatus”).

Having said that, it is possible to actually model the climate system while including the heat capacity, namely diffusion of heat into and out of the oceans, and include the solar and anthropogenic forcings and find out that by introducing the the solar forcing, one can get a much better fit to the 20th century warming, in which the climate sensitivity is much smaller. (Typically 1°C per CO2 doubling compared with the IPCC's canonical range of 1.5 to 4.5°C per CO2 doubling).

You can read about it here: Ziskin, S. & Shaviv, N. J., Quantifying the role of solar radiative forcing over the 20th century, Advances in Space Research 50 (2012) 762–776

The low climate sensitivity one obtains this way is actually consistent with other empirical determinations, for example, the lack of any correlation between CO2 variations over the past half billion years and temperature variations. See in particular fig. 6 of a sensitivity analysis I published in 2005.

Fig. 6 from Shaviv (2005) in which I carried out a senisitivity analysis assuming that the sun has a large effect on climate through cosmic ray modulation (right) or that it doesn't (left). Each error bar is the 1σ sensitiviy range obtain from radiative forcing variations over different periods as a function of the average tempeature relative to today.

3) The third point raised is that the allegedly large solar climate link is just based on correlations. This is wrong as well.

To begin with, if the correlations where just spurious, then there would have been no reason for them to continue, but since the analysis that gave the above graph was published, a new one based on 2 more solar cycles worth of satellite altimetry was published as well. If the first correlation was a mere fluke, then there should be no reason for the correlation to continue, but they very clearly do. See Howard, D., Shaviv, N. J., & Svensmark, H. (2015). The Solar and Southern Oscillation Components in the Satellite Altimetry Data. Journal of Geophysical Research: Space Physics, 120, 3297-3306.

In fact, the sun + ENSO explain 71% of the variance in the linearly detrended sea level change. You could think that it doesn't get any better than that! But it does.

This correlation has the correct amplitude and phase that you would expect from (a) the low altitude cloud cover variations seen in sync with the solar cycle which were estimate to cause drive a 1W/m² variation and with (b) the change in the sea surface temperature of 0.1°C over the solar cycle (e.g., see the above paper on climate sensitivity over different time scales where the cloud forcing and sea surface temperatures are discussed). You could again think that it doesn't get any better than that, but it does yet again! We have a mechanism to explain it all. It is through modulation of the cloud cover.

Linearly de-trended altimetry based Sea level (blue dots) and a fit which includes only the solar cycle and el Ñino (from Howard et al. 2015). One can clearly see that the solar cycle has a prominant contribution. It is in fact consistent in phase and in amplitude to the Shaviv (2008) result (local copy).

You can read more about the big picture in a summary I wrote a couple of years ago when on sabbatical at the Inistute for Advanced Studies in Princeton. So it isn't correlations. It is part of a wider consistent picture with endless empirical results and physical mechanisms to explain it.

To sum up, one cannot avoid the conclusion that the sun has a much larger effect on climate than the IPCC is willing to admit. It is not rubbish, or just correlations, nor is it inconsistent with observations on temperature or sea level.

After the committee, I was taken for a tour of the Bundestag by the nuclear physicist Dr. Götz Ruprecht, which of course includes the Reichstag building. Besides seeing interesting architecture, the most interesting thing was a discussion with Ruprecht on the Dual Fluid reactor concept that he and his colleagues are working on. It is a fast reactor that can use natural Uranium and Thorium, it can treat high-level waste (i.e., ensure there is no waste with a half life longer than a few centuries), it is inherently safe because it has such a strong negative temperature dependence of the reaction rates (as opposed for example to Graphite reactors like Chernobyl's) and because it includes passive heat based safety valves as well. Because of its high operating temperature, it can be used for additional things such as generation of hydrogen for clean fuel. And, electricity production should be less than 1 cent per kWhr (even cheaper than the typical 3 cents for present day nuclear, and compared with the 30 euro-cents per kWhr that one pays in Germany because of all the effective subsidies of ineffective alternative energy sources, or the 11 euro-cents per kWhr I pay in Israel, where there are much less of these subsidies). Of course, there is no chance that something like that will be developed in Europe with the current atmosphere in Europe and Germany in particular, where nuclear is phasing out (and soon coal... at least until the first catastrophic power outage that they will sure have). If you're a billionaire that wants to invest in a project that will lead the future energy production, contact me :-)

Another interesting thing that happened to me last week is that I lost my hearing in one ear (possibly from swimming a few days earlier, or the flights I had), and regained it after 5 days or so, quite a strange experience I'll write soon about. It included the very strange effect of diplacusis in which I heard a different pitch in each ear (up to a 1.5 semitone difference). I'll write about this strange experience in my next post.

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22 minute talk summarizing my views on global warming

August 4, 2019, 1:46 pm

≫ Next: Forbes censored an interview with me

≪ Previous: My experience at the German Bundestag's Environment Committee in a pre-COP24 discussion

Blog topic:

cosmic rays, global warming, personal research, politics, weather & climate

Just over a week ago I gave a 20 minute talk (which lasted almost 22 min) about the role that the sun plays in global warming in the Heartland institute's climate conference in DC. Since it came online and since I think this is about as good a summary I can make in 20 odd minutes, here it is brought again for posterity.

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Forbes censored an interview with me

August 10, 2019, 9:13 am

≫ Next: Solar Debunking Arguments are Defunct

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Blog topic:

cosmic rays, global warming, personal research, politics, weather & climate

A few days ago I was interviewed by Doron Levin, for an article to appear online on forbes.com. After having seen a draft (to make sure that I am quoted correctly), I told him good luck with getting it published, as I doubted it will. Why? Because a year ago I was interviewed by a reporter working for Bloomberg, while the cities of San Francisco and Oakland were deliberating a climate change lawsuit against Exxon-Mobil (which the latter won!), only to find out that their editorial board decided that it is inappropriate to publish an interview with a heretic like me. Doron’s reply was to assure me that Forbes’ current model of the publication online allows relative freedom with “relatively little interference from editors”. Yeah Sure.

After the article went online yesterday and Doron e-mailed so, I saw how much relative exposure it received. It had already more than 40000 impressions in a matter of a couple of hours. Impressive. All that took place while I was relaxing with my family on a Tel-Aviv beach. But this didn’t last long. Although I continued to relax at the beach, the article was taken down for “failing to meet our editorial standards”, which apparently means conforming to whatever is considered politically correct about climate change.

The piece itself is (or was, or will be?) found here. A copy was posted here.

In any case, the main goal of this post is to provide the scientific backing for the main points I raised in the interview. Here it comes.

First and foremost, I claim that the sun has a large effect on climate and that the IPCC is ignoring this effect. This I showed when I studied the heat going into the oceans using 3 independent datasets - ocean heat content, sea surface temperature, and most impressively, tide gauge records (see reference #1 below), and found the same thing in a subsequent study based on another data set, that of satellite altimetry (see reference #2 below). Note that both are refereed publications in the journal of geophysical research, which is the bread and butter journal of geophysics. So no one can claim it was published in obscure journals, yet, even though the first paper has been published already in 2008, it has been totally ignored by the climate community. In fact, there is no paper (right or wrong) that tried to invalidate it. Clearly then, the community has to take it into consideration. Moreover, when one considers that the sun has a large effect on climate, the 20th century warming is much better explained (with a much smaller residual). See reference #3 below, again refereed).

I should add that there are a few claims that the sun cannot affect the climate because of various reasons, none holds water. Here is why:

The first claims is that “the sun cannot have a large effect on climate because changes in the irradiance are too small to do so, and we don’t know of a mechanism that can”. This is irrelevant because given that the oceans prove that the sun has a large effect on climate, we must consider it even if we don’t know how it comes about. Often in science we are forced to accept a theory we don’t fully understand because the empirical evidence suggests so. Mendelian genetics explained reality pretty well (though we now know it is a bit more complicated) a century before Watson and Crick showed what the underlying mechanism is. Does it mean that we should have discarded Mendelian genetics for a century without knowing the mechanism? Pauli postulated the existence of the neutrino a quarter of a century before it was actually detected. Similarly, almost all cosmologists and particle physicists assume that dark matter exists, because an overwhelming amount of evidence suggests so, and because alternatives simply don’t work (mainly MOND, e.g., as a post-doc and I have shown in a paper as well as many others). However, we don’t really know what dark matter really is (there are many suggestions), but its existance has to be considered. Having said that, we actually do see very clear empirical evidence pointing to the link, as I describe below.
The second claim is that “solar activity decreased from the 1990’s but the temperature continued to increase. So the sun cannot be the reason for the heating”. It is wrong at several levels. First, one has to realize that the temperature anomaly at a given time is not some fixed factor times the forcing at the time. This is because the system has a finite heat capacity and various interesting feedbacks. Without properly modeling it, erroneous conclusions can be reached. A simple example is ruling out the solar flux as the major source of heat because between noon time and say 2pm, the solar flux is decreasing but the temperature is increasing! (Similarly, the average solar flux is decreasing during the month of July in the northern hemisphere, but the temperature is increasing). Solar activity has been high over the latter half of the 20th century such that even after solar activity started to decreases, the temperature should continue increasing for a decade or so, albeit at a lower pace. Second, the above argument is extremely simplistic. Proper modeling has to consider that human have contributed as well to the net positive forcing. And indeed, when one considers both the large effect that the sun has, and the anthropogenic forcing, one can explain 20th century climate change if climate sensitivity is on the low side, much better than the IPCC models that exclude the large effect that the sun has, but assume a large climate sensitivity instead. See reference #3 below, as well as Roy Spencer’s short talk showing that climate models generally give a much larger temperature increase than has been observed over the past 2 decades.
The third claim is that when 20th temperature changes are compared with solar activity and anthropogenic forcing, one doesn’t see the 11 year solar cycle in the temperature data, which can be used to place an upper limit on the solar effect. This faulty argument is related to the previous one. It too assumes that the temperature should be proportional to the radiative forcing at any instant, and because the temperature variations over the 11 year solar cycle are only of order 0.1°C, the contribution to 20th century warming should be similar since the secular increase in the solar forcing is comparable to the variations over the 11 year solar cycle. However, the large heat capacity of the oceans damps any temperature variations on short time scales. Proper modeling reveals that an 0.1°C variation over the solar cycle should actually correspond to a variation much larger on the centennial time scale, in fact, about half to two thirds of the warming (see reference #3 below and my comments about the BEST analysis from Berkeley who “proved” that the sun cannot have a large climate effect based on the above argument).

[Edit: See my more detailed rebuttal of the attack on solar forcing that appeared a day later on Forbes]

As I said above, we now know from significant empirical data where the solar climate link comes from. It is through solar wind modulation of the galactic cosmic ray flux which governs the amount of atmospheric ionization, and which in turn affects the formation of cloud condensation nuclei and therefore cloud properties (e.g., lifetime and reflectivity). How do we know that?

When the sun has gusts in the solar wind, it causes several day long reductions in the flux of cosmic rays reaching Earth, called Forbush decreases. We see as a response changes in the aerosols and in cloud properties, just as expected. See references 4 & 5 below.
There are large cosmic ray flux variations over geological time scales that are not related to solar activity but instead to our location in the Milky Way and the changing galactic environment. You can reconstruct the cosmic ray flux using meteorites and find that the 7 ice-age epochs over the past 1 billion years all appeared when the cosmic ray flux was high (see references 6 & 7 below). On a bit shorter time scales, the vertical motion of the solar system clearly manifests itself as a 32 million year oscillations in the temperature (15 periods over the past half billion years! See reference 8 below). Namely, there are very clear indications that independent variations in the cosmic ray flux affect the climate.
Cloud cover varies over the 11 year solar cycle (e.g., reference 9 below). This by itself is not proof that the link is through cosmic rays, since there are several things that change with the solar cycle. However, one particularly interesting aspect is that the cloud cover variation are asymmetrical between odd and even cycles, just as cosmic rays are, and unlike other solar related variables that are blind to the fact that the real cycle is 22 years (Polarity returns back to the same state after two switches, hence, 22 years. The asymmetry arises from the fact that cosmic rays are primarily positive particles, and the sun is rotating such that there is a clear helicity to the field configuration).
There are several experimental results showing that ions increase the nucleation and formation of a few nm sized aerosols and increase the survival of those aerosols as they grow to become 50 nm sized cloud condensation nuclei. A few examples are given in references 10-13.

One should be aware that we are still missing the last piece of the puzzle, which is to take the various mechanisms, plug them into a global aerosol model and see that there is a sufficiently large variation in the cloud condensation nuclei. This takes time, but compared with the aforementioned examples of genetics, neutrinos or dark matter, it will definitely take us much less to provide this last piece, but in any case, the evidence should have forced the community to seriously consider it already.

Nonetheless, even with the above large body of empirical evidence, the link has been attacked left and right. A really small number has been valid and interesting, but not to the extent to invalidate the existence of a cosmic ray climate link, just to modify our understanding of it. The rest has been mostly bad science, as I exemplify below.

One of the main critiques arises when people look for the cosmic ray climate link but find none. In all those cases were no effect is seen, the authors didn’t estimate the size of the effect they expected and compare it with the noise level in the data. For example, if one considers only a small patch of the atmosphere above oceans, then the day to day fluctuations in the cloud cover are large compared with the Forbush decrease signal. Similarly, not seeing an effect over 10’s of thousands of years because of Earth’s magnetic field changes, is not surprising because switching off Earth’s magnetic field altogether is expected to give rise to a 1°C effect, which is notably smaller than the climate variations seen over these time scales (presumably because of the Milankovich cycles).
The cosmic ray climate link over geological time scales was attacked by several papers. Only one raised a valid scientific point, which is that the original analysis of Jan Veizer and I didn’t consider the effect that the ocean pH (affected by atmospheric CO2) has on the Oxygen 18 data. When that was taken into account, we modified our best estimate for climate sensitivity to be 1 to 1.5°C per CO2 doubling. Other analyses are blatantly wrong, such as faulty statistical analysis or data handling (see summaries here and here), or even simple arithmetic mistakes! (see here).
The last set of critiques are actually part of a healthy scientific discourse about the mechanism that is responsible for linking atmospheric ionization with cloud condensation nuclei. Papers like this discuss the possibility that ion induced nucleation could be the physical mechanism linking ionization changes with variations in the cloud condensation nuclei number density. However, even if we don’t fully understand the underlaying mechanism, ruling out a particular suggested mechanism doesn’t mean that other possibilities do not exist (in fact, they do, see ref #13 below). When Pauling and Corey suggested the triple helix model for DNA in 1953, they were off, but it wasn’t a reason to discard the whole idea of genetics.

References:

Shaviv, N. J. Using the oceans as a calorimeter to quantify the solar radiative forcing. J. Geophys. Res. (Space Phys.) 113, 11101 (2008) local version (not paywalled)
Howard, D., Shaviv, N. J., Svensmark, H., The solar and Southern Oscillation components in the satellite altimetry data, J. Geophys. Res. Space Physics, 120, 3297–3306 (2015)
Ziskin, S., Shaviv, N. J., Quantifying the role of solar radiative forcing over the 20th century, Advances in Space Research 50, 762–776, (2012). local version (not paywalled)
Svensmark, H., Bondo, T. & Svensmark, J. Cosmic ray decreases affect atmospheric aerosols and clouds. Geophys. Res. Lett. 36, 15101–1510 (2009)
Svensmark, J., Enghoff, M. B., Shaviv, N. J. & Svensmark, H. The response of clouds and aerosols to cosmic ray decreases. J. Geophys. Res.: Space Phys. 121, 8152–8181 (2016).
Shaviv, N. J. Cosmic ray diffusion from the galactic spiral arms, iron meteorites, and a possible climatic connection. Phys. Rev. Lett. 89, 051102–05110 (2002)
Shaviv, N. J. The spiral structure of the Milky Way, cosmic rays, and ice age epochs on Earth. New Astron. 8, 39–77 (2003)
Shaviv, N. J., Prokoph, A., Veizer, J., Is the Solar System's Galactic Motion Imprinted in the Phanerozoic Climate? Scientific Reports volume 4, Article number: 6150 (2014)
Svensmark, H. & Friis-Christensen, E. Variation of cosmic ray flux and global cloud coverage—a missing link in solar-climate relationships. J. Atmos. Sol. -Terr. Phys. 59, 1225–1232 (1997).
Svensmark, H., Pedersen, J. O. P., Marsh, N. D., Enghoff, M. B. & Uggerhøj, U. I. Experimental evidence for the role of ions in particle nucleation under atmospheric conditions. Proc. R. Soc. A 463, 385–396 (2007)
Kirkby, J. et al. Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation. Nature 476, 429–433 (2011).
Svensmark, H., Enghoff, M. B. & Pedersen, J. O. P. Response of cloud condensation nuclei (>50 nm) to changes in ion-nucleation. Phys. Lett. A 377, 2343–2347 (2013).
Svensmark, H., Enghoff, M. B., Shaviv, N. J., Svensmark J., Increased ionization supports growth of aerosols into cloud condensation nuclei, Nature Communications 8, Article number: 2199 (2017)

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Solar Debunking Arguments are Defunct

August 11, 2019, 6:58 am

≫ Next: Critique of “Discrepancy in scientific authority and media visibility of climate change scientists and contrarians”

≪ Previous: Forbes censored an interview with me

Blog topic:

global warming, personal research, weather & climate

An article interviewing me was removed yesterday from forbes. Instead, they published an article by Meteorologist Prof. Marshall Shepherd that claims that the sun has no effect on climate. That article, however, falls to the same pitfalls that pointed out on my blog yesterday.

Specifically, why is Shepherd’s arguments faulty? Although I addressed them yesterday, here they are brought again more explicitly and with figures.

First, and foremost, Shepherd ignores the clear evidence that shows that the sun has a large effect on climate, and quantifies it. This graph is from the Shaviv 2008 (#1 in the reference below):

Figure 1: Reconstructed Solar constant (dashed red line) and sea level change rate based on Tide Gauge records as a function of time (solid blue line with 1 sigma error region in gray).

As you can see, there is a very clear correlation between solar activity and the rate of change of the sea level. On short time scales most of the sea level change is due to changes in the heat going into the oceans, such that we can quantify the solar radiative forcing this way. It is found to be an order of magnitude larger than changes in the irradiance, which is what the IPCC is claiming is to be the solar contribution.

After that work was published there was not a single paper that tried to refute it. Instead, additional satellite altimetry data covering two more solar cycles just revealed the same. In fact, the sun + el Niño Southern Oscillation can explain almost all the sea level variations minus the long term linear trend (caused by ice caps melting). This is from Howard et al. 2015 (see ref. #2 at the end):

Figure 2: Satellite Altimetry based sea level (minus linear trend) in dashed blue points. Red is best fit model which includes solar cycle + el niño souther oscillation.

Clearly, the sun continues to have a clear effect on the climate. Note that it is impossible to explain the large variations through a feedback in the system because that would give the wrong phase in the heat content response.

What does that imply?

First, since solar activity increased over the 20th century, it should be taken into account. Shepherd’s radiative forcing graph should be modified to be:

Figure 3: Radiative forcing contributions (graph from Shepherd's article) with the following added. The beige is the real solar contribution over the 20^th century. The green is the total forcing (natural + anthropogenic) we get once we include the real solar effect.

The next point to note is that Shepherd claimed that because solar activity stopped increasing from the 1990’s it cannot explain any further warming. This is plain wrong. Consider this example in false logic. The sun cannot be warming us because between noon and 2pm (or so), solar flux decreases while the temperature increases. As a Professor of meteorology, Prof. Shepherd should know about the heat capacity of the oceans such that assuming that the global temperature is something times the CO₂ forcing plus something else times the solar forcing is too much of a simplification.

Instead, one can and should simulate the 20^th century, and beyond, and see that when taking the sun into account, it explains about 1/2 to 2/3s of the 20^th century warming, and that the best climate sensitivity is around 1 to 1.5°C per CO₂ doubling (compared with the 1.5 to 4.5°C of the IPCC). Two points to note here. First, although the best estimate of the solar radiative forcing is a bit less than the combined anthropogenic forcing, because it is spread more evenly over the 20th century, its contribution is larger than the anthropogenic contribution the bulk of which took place more recently. That's why the best fit gives that the solar contribution is 1/2 to 2/3s of the warming. Second, the reason that the best fit requires a smaller climate sensitivity is because the total net radiative forcing is about twice larger. This implies that a smaller sensitivity is required to fit the same observed temperature increase.

Here is my best fit to the 20th century. Solid line is model and dashed is the observed global temperate (See Ziskin & Shaviv, ref. #3 below).

Figure 4: Best fit for a model which allows for a larger solar forcing and a smaller climate sensitivity than the IPCC is willing to admit is there. Top: Model = solid line, NCDC Observations = dashed line). The bottom is the different between the two.

As you can see, the residual of the fit is typically 0.1°C, which is twice smaller than typical fits by CMIP 5 models.

Once we fit the 20th century, we can integrate forward in time. Here I plot the expected warming for many realizations assuming a vanilla flavored emission scenario:

Figure 5: Using best fit models for the 20th century, we can integrate forward in time while making random realizations for volcanoes, solar activity etc.

The actual temperature increase witnessed is totally consistent with the observations. It is much smaller than the CMIP 5 models which the IPCC is using. See image capture from Roy Spencer’s ICCC13 talk:

Figure 6: CMIP5 models vs. actual temperature change based on satellite (RSS/UAH) or reanalyses datasets.

And average warming slopes, together with my predictions:

Figure 7: Warming trends in CMIP5 models vs. actual warming trends based on satellite (RSS/UAH) or reanalyses datasets. The orange bar is our predicted warming trend. Error is from the range of realizations.

Namely, our predictions are totally consistent with the satellite (RSS / UAH, whichever you prefer) and the Reanalyses datasets. Remember, this was obtained for a model which included the real solar contribution which requires a small climate sensitivity.

Shepherd also mentions that the link through cosmic ray flux variations has been debunked. I point the reader to a summary of why those attacks don’t hold any water, which I wrote yesterday.

To summarize, Shepherd did not debunk the solar forcing. His arguments are defunct. Unless he comes up with a very good explanation to the first graph above, he should instead advocate taking solar forcing into account. The fact that forbes hushes up any possibility for having a scientific debate should be considered truly bothersome by anyone who values free speech and scientific debate. Truth will prevail irrespectively.

References:

Shaviv, N. J. Using the oceans as a calorimeter to quantify the solar radiative forcing. J. Geophys. Res. (Space Phys.) 113, 11101 (2008) local version (not paywalled)
Howard, D., Shaviv, N. J., Svensmark, H., The solar and Southern Oscillation components in the satellite altimetry data, J. Geophys. Res. Space Physics, 120, 3297–3306 (2015)
Ziskin, S., Shaviv, N. J., Quantifying the role of solar radiative forcing over the 20th century, Advances in Space Research 50, 762–776, (2012). local version (not paywalled)

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Critique of “Discrepancy in scientific authority and media visibility of climate change scientists and contrarians”

August 17, 2019, 2:21 pm

≫ Next: How Climate Change Pseudoscience Became Publicly Accepted

≪ Previous: Solar Debunking Arguments are Defunct

Blog topic:

general science, global warming, politics, weather & climate

A paper that recently received some media attention is the “Discrepancy in scientific authority and media visibility of climate change scientists and contrarians” by Alexander Michael Petersen, Emmanuel M. Vincent & Anthony LeRoy Westerling, Nature Communications, volume 10, Article number: 3502 (2019). Here is what I think of it.

The critique of this paper is going to be very short, because it has a MAJOR flaw that renders all the results totally meaningless (even as an anecdotal curiosity). The underlying problem with the whole analysis is the way that the lists were composed. Here is how they composed each list:

“Selection of contrarians (CCC). We compiled a list of 386 contrarians by merging three overlapping name lists obtained from three public sources. The first source is the list of former speakers at The Heartland Institute ICCC conference (http://climateconferences.heartland.org/speakers/) over the period 2008–present, providing a representative sample across time; the second source is the list of individuals profiled by the DeSmogblog project; and the third source is drawn from the list of lead authors of the most recent 2015 NIPCC report (the principal summary of CC denial argumentation produced in conjunction with The Heartland Institute, http://climatechangereconsidered.org/).”

“Selection of scientists (CCS). We ranked individuals’ publication profiles according to the net citations $C_i = \sum_{i \in p} c_p$ calculated by summing individual article citation totals ($c_p$) for only the individual articles (indexed by p) included within our WOS CC dataset. In this way, the CCS group is comprised of the 386 most-cited CC scientists, based solely on their CC research.”

As you can see, the selection criteria is completely different. While the list of alarmists, acryonymed CCS (climate change shouters, I think) is selected by the the citations, the list of anti-alarmists, acronymed CCC (Climate Change Comforters, I think ;-) was selected by those who already have more exposure to the media. Then they compare the groups, and what do you know, the group that was selected according to bibliometric impact has a higher bibliometric impact and those selected through public exposure, namely, because they were active in the media, have more public exposure. Duh! (https://www.youtube.com/watch?v=nE7J5zLaefs). This is one of the most obvious selection biases I have seen in my scientific life. It's not a compliment.

Because of this distorted selection, the top CCC is Marc Morano. He isn’t a scientist nor does he pretend to be one, so why do the authors of this “research” compare his null scientific citation record to media appearance ratio with that of scientists? I don’t see that they put Al Gore in the top of the CCS list! He too has a very poor bibliometric impact.

A correct methodology would have been to comprise similar length lists of the top CCC and CCS based on citations alone, and then compare. But I guess it was a little too hard. Let me quote Mark Twain who said that there are “Lies, damned lies, and statistics”. In this case, it is statistics based on highly biased data.

I said before and I’ll say it again. Alarmists should use scientific arguments to bolster their case. The more they use chaff arguments, the more it reflects badly on their ability to defend their scientific case, perhaps because they can’t (e.g., see this).

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How Climate Change Pseudoscience Became Publicly Accepted

September 24, 2019, 1:07 pm

≪ Previous: Critique of “Discrepancy in scientific authority and media visibility of climate change scientists and contrarians”

Blog topic:

economics, general science, global warming, personal research, politics, weather & climate

The I recently wrote an OpEd for the Epoch Times which tries to succinctly capture my main grievances with the global warming scare. Here is brought again with a few comments (and references) added at its end.

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The climate week that is being held in New York City has urged significant action to fight global warming. Given the high costs of the suggested solutions, could it be that the suggested cure is worse than the disease?

As a liberal who grew up in a solar house, I have always been energy conscious and inclined towards activist solutions to environmental issues. I was therefore extremely surprised when my research as an astrophysicist led me to the conclusion that climate change is more complicated than we are led to believe. The disease is much more benign; and a simple palliative solution lies in front of our eyes.

To begin with, the story we hear in the media, that most of the 20th century warming is anthropogenic, that the climate is very sensitive to changes in CO2, and that future warming will therefore be large and will happen very soon, is simply not supported by any direct evidence, only a shaky line of circular reasoning. We “know” that humans must have caused some warming, we see warming, we don’t know of anything else that could have caused the warming, so it adds up.

However, there is no calculation based on first principles that leads to a large warming by CO2, none. Mind you, the IPCC (Intergovernmental Panel on Climate Change) reports state that doubling CO2 will increase the temperatures by anywhere from 1.5 to 4.5°C, a huge range of uncertainty that dates back to the Charney committee from 1979.

In fact, there is no evidence on any time scale showing that CO2 variations or other changes to the energy budget cause large temperature variations. There is however evidence to the contrary. 10-fold variations in the CO2 over the past half billion years have no correlation whatsoever with temperature; likewise, the climate response to large volcanic eruptions such as Krakatoa.

Both examples lead to the inescapable upper limit of 1.5°C per CO2 doubling—much more modest than the sensitive IPCC climate models predict. However, the large sensitivity of the latter is required in order to explain 20th century warming, or so it is erroneously thought.

In 2008 I showed, using various data sets that span as much as a century, that the amount of heat going into the oceans in sync with the 11-year solar cycle is an order of magnitude larger than the relatively small effect expected from just changes in the total solar output. Namely, solar activity variations translate into large changes in the so called radiative forcing on the climate.

Since solar activity significantly increased over the 20th century, a significant fraction of the warming should be then attributed to the sun, and because the overall change in the radiative forcing due to CO2 and solar activity is much larger, climate sensitivity should be on the low side (about 1 to 1.5°C per CO2 doubling).

In the decade following the publication of the above, not only was the paper uncontested, more data, this time from satellites, confirmed the large variations associated with solar activity. In light of this hard data, it should be evident by now that a large part of the warming is not human, and that future warming from any given emission scenario will be much smaller.

Alas, because the climate community developed a blind spot to any evidence that should raise a red flag, such as the aforementioned examples or the much smaller tropospheric warming over the past two decades than models predicted, the rest of the public sees a very distorted view of climate change — a shaky scientific picture that is full of inconsistencies became one of certain calamity.

With this public mindset, phenomena such as that of child activist Greta Thunberg are no surprise. Most bothersome however is that this mindset has compromised the ability to convey the science to the public.

One example from the past month is an interview I gave Forbes. A few hours after the article was posted online, it was removed by the editors “for failing to meet our editorial standards”. The fact that it has become politically incorrect to have any scientific discussion has led the public to accept the pseudo-argumentation supporting the catastrophic scenarios.

Evidence for warming doesn’t tell us what caused the warming, and any time someone has to appeal to the so called 97 percent consensus he or she is doing so because his or her scientific arguments are not strong enough. Science is not a democracy.

Whether or not the Western world will overcome this ongoing hysteria in the near future, it is clear that on a time scale of a decade or two it would be a thing of the past. Not only will there be growing inconsistencies between model and data, a much stronger force will change the rules of the game.

Once China realizes it cannot rely on coal anymore it will start investing heavily in nuclear power to supply its remarkably increasing energy needs, at which point the West will not fall behind. We will then have cheap and clean energy producing carbon neutral fuel, and even cheap fertilizers that will make the recently troubling slash and burn agriculture redundant.

The West would then realize that global warming never was and never will be a serious problem. In the meantime, the extra CO2 in the atmosphere would even increase agriculture yields, as it has been found to do in arid regions in particular. It is plant food after all.

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