Physicists at CERN (the European Organization for Nuclear Research) created something of an online kerfuffle last month when they sought to improve our understanding of cosmic rays and clouds.
While their experiment made novel findings on particle formation, it was the blogosphere’s claims about the implications for climate change that were really interesting.
Previous articles on The Conversation have outlined why the greenhouse effect is real and why increasing greenhouse gases drive global warming.
Against this understanding, some commentators argue for a range of speculative and unsubstantiated mechanisms that will supposedly counteract future global warming, or that provide an alternative explanation for 20th century climate change.
While these arguments do not stand the scrutiny of the peer-reviewed literature, they are prominent in the blogosphere.
There are two common arguments levelled against the risk associated with a doubling or more of atmospheric carbon dioxide.
“Don’t worry – the climate system will stop itself from warming too much.”
The first argument is based on the idea that negative feedback processes within the climate system will limit or cap future warming – to a level not much warmer than present.
In the context of human-induced climate change, a positive feedback is a natural mechanism that enhances the warming caused by greenhouse gases. A negative feedback is one that reduces the warming caused by greenhouse gases.
Increasing water vapour in the atmosphere is the most important positive feedback mechanism for the enhanced greenhouse effect. Like carbon dioxide and methane, water vapour is a powerful greenhouse gas. As the climate system warms, the atmosphere can hold more water vapour, greatly enhancing the amount of warming from carbon dioxide.
So increasing carbon dioxide concentrations are the agent of change, or the primary driver of warming, while increasing water vapour is the climate system’s response to that warming. Most estimates suggest that water vapour feedback approximately doubles the warming from increasing carbon dioxide alone.
Increased moisture in the atmosphere also leads to changes in cloud type and cloud cover.
Exactly what will happen to clouds is one of the major sources of uncertainty when it comes to future climate change. The uncertainty is due to the sheer complexity of clouds and their relationship to the Earth’s radiation budget.
We expect that some changes in cloud properties will slightly reduce the impact of greenhouse warming. For example, clouds will most likely be more reflective as the atmosphere warms, reflecting more incoming solar energy back out to space.
However, it is also possible that the heat-trapping effect of high clouds will increase in response to warming, offsetting the effect of more reflection of solar energy. So the net effect of these cloud feedbacks is very uncertain.
Again, it is important to keep in mind that feedback processes do not drive climate change. Rather, they can accentuate or moderate changes associated with external influences on the climate system.
Changes to cloud are regularly cited in the blogosphere as a factor that will halt future warming at a level we can cope with. However this argument is entirely inconsistent with another that is regularly presented on blogs: that the Earth was much hotter in the past.
The latter argument is true; the Earth has indeed been much hotter in the geological past, especially when greenhouse gas concentrations have been high.
In this way, we know very clearly that clouds contain no magical mechanism that limits future warming to a level that is benign to human civilisation. Unfortunately, the climate system is not cognisant of what will cause us disruption and does not self-regulate for our own interests.
“Don’t worry, something else will stop the climate system warming too much”
The other argument put forward against climate change is that of a “missing climate forcing”.
Climate forcing is an external mechanism, such as large volcanic eruptions, that can alter the climate system and cause warming or cooling. These are distinct from feedbacks, but frequently confused on the web.
The “missing climate forcing” argument contends climate scientists have completely botched their understanding of what factors push and pull the climate system. Alternatively, they have neglected to account for some very important, additional mechanism that either explains 20th century changes or limits future warming.
Again, the natural limit on future warming to benign levels is disingenuous. But does the idea of “a missing forcing” have any credence when it comes to explaining 20th century changes?
One of the more popular “missing forcings” in the blogosphere is the cosmic ray hypothesis.
The cosmic ray hypothesis
The base proposition is that cosmic rays, or charged particles from space (predominantly protons), enhance the formation of tiny new particles in the upper atmosphere.
Clouds need particles (aerosols) to form. Cosmic rays have been proposed as a factor that assists cloud formation and that enhances the reflectivity of clouds.
The idea of cosmic rays as a missing forcing goes a little bit like this …
Before the 20th century, the Earth was bombarded with more cosmic rays than at present. This resulted in greater cloud cover and higher cloud reflectivity. This meant less sunlight at the surface of the Earth and a cooler climate system.
Over the course of the 20th century, changes in the sun’s magnetic field caused a reduction in cosmic rays reaching the Earth, which in turn meant fewer clouds. Fewer clouds mean more sunlight reaching the surface. This chain of causality is proposed as an explanation for the global warming trend measured by instruments over the past century.
While observations do not support this claim, an interesting experiment was recently carried out by physicists at CERN seeking to improve our understanding of cosmic rays and clouds.
The actual science regarding new particle formation (nucleation) is interesting in itself. But this experiment is particularly interesting because of the reaction it attracted in the blogosphere, as to the implication of these results for climate change science.
The cosmic ray experiment at CERN
First, let’s take a look at the experiment and what the researchers discovered.
The design of the experiment was to keep a chamber (shielded from cosmic rays) at a fixed relative humidity and then introduce increasing concentrations of sulphuric acid at three different temperatures (approximately -20, 5 and 20° Celsius, representing upper middle and lower levels of the atmosphere). Sulphuric acid is an important substance in the formation of particles (sulphate aerosols) in the real atmosphere.
The researchers found the production of new particles increased with increasing sulphuric acid concentrations and decreasing temperature. The cosmic ray shielding was removed and the nucleation rate increased by up to a factor of ten. This is a new and novel result.
Even more interesting was that, even though they took measures to evacuate all other substances from the chamber, the nucleated particles all contained nitrogen, which is absent in sulphuric acid and water. They found that the nitrogen had originated from ammonia, which was present in undetectable quantities, but had participated in the nucleation process.
The CERN team subsequently repeated the experiment, but this time added small (although measurable) quantities of ammonia to the chamber. Again, the cosmic rays resulted in a tenfold increase in the nucleation rate. The addition of ammonia, however, increased the nucleation rate by 100-1000 fold.
Therefore, ammonia is obviously very important for the production of new particles, as are cosmic rays.
All in all, this was a well-constructed experiment. The results have provided unprecedented observations of the initial stages of new particle formation and invaluable empirical information for scientists working on theoretical and computer models of atmospheric nucleation.
Is this significant for our understanding of climate change?
Now let’s turn our attention to the blogosphere, where it has been claimed these results strengthen the hypothesis that recent warming can be attributed to cosmic rays; or at least a lack of them.
In fact, by itself, the CERN experiment showed there may be a link between cosmic rays and the formation of aerosols in the atmosphere.
The experiment did not demonstrate cosmic rays influence cloud production specifically. Further, the experiment did not show that increases or decreases in cosmic rays cause a measurable impact on climate.
Further still, the experiment in no way demonstrated that decreases in cosmic rays over the 20th century caused recent global warming.
To evaluate the impact of cosmic rays on climate, their effect on clouds needs to be weighed against the many other processes that we know affect cloud cover and cloud reflectivity.
The link between new particle production and cloud seeds
The particles the CERN researchers produced in the laboratory were a few nanometres in radius (one billionth of a metre). These particles are known as condensation nuclei (CN).
Out in the real atmosphere, under typical conditions, a particle must be (at least) 50 nanometres in radius to act as a “seed” for a cloud droplet. These particles are known as cloud condensation nuclei (CCN).
For a condensation nuclei to become a CCN, and capable of seeding a cloud, it must increase its radius approximately tenfold and its volume 1000-fold.
Did the increase in CN concentration which CERN researchers observed in the laboratory also imply an increase in the number of CCN? We still don’t know the answer to that.
Moreover, if there is a significant increase in CCN from cosmic rays, does it provide comparable numbers of CCN to those produced by other sources? There are many natural and human sources of aerosols. These include forest fires, volcanic eruptions and industrial pollution, all of which produce CCN in the atmosphere.
In fact, there is no shortage of CCN in the atmosphere. Based on our current understanding, the direct emission of CCN from all other sources would far outweigh the possible production of CCN from cosmic rays.
The link between increased CCN and clouds
The link between changes in aerosol particles and subsequent changes in the reflectivity and the area of clouds is worthy of separate discussion in itself.
But we can summarise here that satellite and upper atmosphere measurements have demonstrated that increased particles in the atmosphere can modify the reflectivity of clouds. There is also evidence that aerosols can increase local cloud amount.
If global increases or decreases in cloud reflectivity or cloud amount are large enough, they will impact on the Earth’s radiation budget.
In terms of climate change in the past 100 years or more, our current understanding is that observed increases in atmospheric aerosols – mostly from industrial pollution and biomass burning – have had a net cooling effect on climate; partially counteracting warming due to increasing greenhouse gases.
Some of this is due to the direct effects of aerosols on solar radiation, and some is due to the effects of aerosols on cloud properties (the so-called “indirect” effects of aerosols).
But such particles are short lived, and greenhouse gases will remain in the atmosphere long after the aerosols have disappeared.
To date, there is no body of work or convincing individual study that shows that changes in the amount of cosmic rays reaching Earth have an appreciable effect on cloud extent or cloud reflectivity.
So what’s the conclusion?
Perhaps the most conclusive piece of evidence against a role for cosmic rays in explaining 20th century changes, is the direct observations of cosmic rays and clouds themselves.
It has long been recognised within the field (as opposed to the blogosphere) that trends in cosmic rays are in the wrong direction to explain global warming in recent decades. That is, even if the relationships in the laboratory can be extrapolated to the real world, the effect of cosmic ray changes is more likely to have cooled the planet.
It is also a fact that there is no observable downward trend in global cloud cover.
Considering all the evidence then, one has to jump through many hoops to place cosmic rays as a significant driver of 20th century climate. The required leaps of logic are both unconvincing and unpublished.
So there is little evidence to suggest that observed global warming has been caused by cosmic rays.
The hypothesis also studiously ignores the large range of evidence showing increasing carbon dioxide as the dominant cause of 20th century global warming.
Such claims on the web are, therefore, perhaps hopeful at best and misinformation at worst. Linking these claims to the recent work at CERN does a great disservice to the interesting and important results from those researchers.
Taken in overall context, the impact of cosmic rays is not likely to have a large or significant influence on future climate change either.
As with all arguments put forward against our understanding of the enhanced greenhouse effect, cloud uncertainties and the cosmic ray hypothesis provide absolutely nothing to suggest it is OK to go ahead and double atmospheric carbon dioxide concentrations over the next century.
Thanks to Dr Leon Rotstayn of CSIRO Marine and Atmospheric Research for providing an expert review and valuable suggestions for this article.
The Conversation
Comments (71)
Comments on this article are now closed.
Alvin Stone
(logged in via Facebook)
This is one of the clearest explanations I have read of the role of cosmic rays in cloud production and what the CERN experiment really means. Great stuff.
John C
(logged in via email @gmail.com)
Thank you Karl. Much appreciated.
Mark Harrigan
Dr (logged in via email @tpg.com.au)
The evidence continues to mount http://www.agu.org/pubs/crossref/2011/2011GL048794.shtml
but there are so many who still refuse to listen
http://skepticalscience.com/The-Earth-continues-to-build-up-heat.html
Doug Cotton
(IT Manager)
I'll leave you will a couple of thoughts ...
News today: Opposition to Australia's Carbon tax has increased by 6% to 59%.
And the evidence against the IPCC has already been revealed at Climategate. Lindzen and Douglass summarised it in an article just published:
"This refers to the release of thousands of emails, commented code, etc. from the Climate Research Unit at the University of East Anglia. The land based instrumental temperature record was not the primary focus of the problems revealed in these documents. Rather, the explicit evidence of the manipulation of proxy records used in paleoclimate reconstructions, suppression of other viewpoints, manipulation of the IPCC process, and intimidation of journal editors were all evidence of serious breaches of ethics. "
Mark Harrigan
Dr (logged in via email @tpg.com.au)
Published where? All the inquiries into the east Anglia email issue have exonerated anyone of misdoing.
Are you suggesting a conspiracy? or do you actually have any new evidence to substantiate these allegations?
James Szabadics
Technical Development and R&D Manager, Plantation Timber Industry (logged in via email @technologist.com)
Mark,
your blog and 2008 3 year old paper is interesting but look at current data and we see interesting short term (5-10 year) changes.
RE The rate of change of sea level:
Sea levels long term trend is fairly linear and reasonably stable around 3.2mm per year. However since 2006 the rate of sea level rise has decellerated, hardly a long term trend change but this 5 yr deviation from the long term sea level rise trend is in an unexpected direction if heat is building up in the system because…
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Mark Harrigan
Dr (logged in via email @tpg.com.au)
The paper was published in 2011 - it is not 3 years old - read it more closely.
Climate is complex - perhpas you need to look at the full picture.
http://climate.nasa.gov/keyIndicators/
In relation to the heat content graph you are only looking at 700m - as my links make clear the heat content is being stored in the depper ocean.
Another case of denailist cherry picking by you perhaps??
James Szabadics
Technical Development and R&D Manager, Plantation Timber Industry (logged in via email @technologist.com)
Mark - the paper you linked to only looks at data up to 2008.
I have provided links to the full time series graphs to present day which is not cherry picking at least not in my books.
If you have a data set showing OHC timeseries in the deeper ocean could you please provide the link as far as I was aware there is no equvalent to ARGO that goes to the sea floor giving a global picture of deep ocean heat content..
I would like to know what the timeseries of OHC in the ocean deeper than 700m looks like.
Mark Harrigan
Dr (logged in via email @tpg.com.au)
Look at the graph on skeptical science for heat content -
http://www.skepticalscience.com/The-Earth-continues-to-build-up-heat.html
says it all.
The fact heat content has levelled somehwat after about 2008 merely suggests it's somewhere else. Trenberth has suggested deeper oceans - google it
James Szabadics
Technical Development and R&D Manager, Plantation Timber Industry (logged in via email @technologist.com)
I dont think there is any global data capture for OHC depper than 700m. It is speculation. Trenberth speculates that this is where the missing heat is, he doesnt measure it in a global systematic way over time.
If you start with an assumption that heat is still building up but every place you can easily measure tells you its stopped then you assume all the heat is being sequestered where it isnt measured.
Lets assume you are right. When will the earth systems building heat show up in the lower troposphere?
Doug Cotton
(IT Manager)
Knox and Douglass rubbished Trenberth's "missing heat" here
http://www.pas.rochester.edu/~douglass/papers/KD_InPress_final.pdf
but what was interesting in Trenberth's article on Skeptical Science was the curved trend line constructed for sea surface temperatures (SST) showing a maximum around 2006 and now declining. With 2011 being cooler than 2010, the decline must have steepened since he did his plot which is shown here: http://climate-change-theory.com/seasurface.jpg
It is also worth noting that there has been a significant breakout from the previously increasing sea level plot and levels are now falling and are back to those of about two years ago. This does not appear to be just random noise and it ties in with the SST decline.
Peter Doidge
(Mr)
James, when you claim that "I dont think there is any global data capture for OHC depper than 700m", and that suggestions that "missing heat" is going into the abyssal ocean are "speculation", lacking evidence in support, you seem to imply that there is no evidence at all for warming of the deep oceans. I dno not believe that this is correct. See, for example, the paper by Purkey and Johnson: http://www.pmel.noaa.gov/people/gjohnson/gcj_3w.pdf
From the Abstract: "Abyssal global and deep Southern Ocean temperature trends are quantified between the 1990s and 2000s to
assess the role of recent warming of these regions in global heat and sea level budgets......warming in these regions, ventilated primarily by Antarctic Bottom Water, accounts for a statistically significant fraction of the present global energy and sea level budgets."
James Szabadics
Technical Development and R&D Manager, Plantation Timber Industry (logged in via email @technologist.com)
Peter,
The paper also states that they estimate rather than measure the trend. OHC 700 is collected by a global system of floating buoys (ARGO) that regularly descend to 700m depth and obtain a profile. There is no equivalent system that does the same thing for the ocean heat content deeper than 700m.
The paper you link to takes 2 snapshots 20 years apart with a total of 28 hydrographic surveys some from the 1990s and some from 2010 to estimate a trend. We have no montly or annual timeseries…
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Doug Cotton
(IT Manager)
If you think about it, it does not make much sense that solar insolation would heat deeper water more than shallow water. But suppose there really has been excessive heat stored deep down. It does not follow that carbon dioxide has caused this. For example, just suppose 2,000 nuclear tests last century caused cavities, cracks, crevices etc in the crust (under the ocean) which are now letting core heat escape more rapidly in such damaged areas. If water fills a large cavity then the heat will…
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Doug Cotton
(IT Manager)
There is no excuse for looking only at data up to 2008, when the main thrust of the argument is that there has been a very significant change since then which is not just random noise. If the sea level plot were a chart of my shares, I can assure you I'd be selling.
There are four contributors to this thread (James Szabadics, John Nicols, Toby James and myself) who would all agree that "warmists" have been seriously mistaken about the role of carbon dioxide in the atmosphere. Perhaps the most…
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Doug Cotton
(IT Manager)
Look at NASA data http://discover.itsc.uah.edu/amsutemps/execute.csh?amsutemps and note that at every level from sea surface to 102000 feet the temperatures in 2011 have been cooler than on the corresponding dates in 2010. Only at the two highest levels 36Km and 41Km are the temperatures very similar. Every other level shows significant cooling.
Now, this happened when carbon dioxide was the highest in recent centuries. So this proves that the atmosphere can cool despite carbon dioxide levels. There is no other "excuse" that would negate the supposed effect of carbon dioxide. There is no such effect, and never will be.
James Szabadics
Technical Development and R&D Manager, Plantation Timber Industry (logged in via email @technologist.com)
Karl, It is great that you have raised peoples awareness of the possible links between GCR and slight variations in cloud cover and aerosols that could impact the radiative budget through variations in Earth Albedo.
A few points need to be made however:
1) This is not a blogosphere theory. The links between Forbush events and cloud cover have been investigated in many papers. Dr Henrik Svensmark of the Danish Space Institute has at least a dozen papers published in scientific Journals on GCR…
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Michael J. I. Brown
(ARC Future Fellow and Senior Lecturer at Monash University)
The original theory wasn't from the blogsphere, and the authors of the above article didn't claim that it was. They did note that the blogsphere has made many claims about the implications of the CERN CLOUD experiment, which go far beyond the conclusions made by CERN CLOUD scientists. They also noted that the blogsphere is quite enthusiastic about cosmic rays as being a missing forcing, and in many cases it is clear that this enthusiasm is motivated by a desire to minimise the role of CO2 in climate.
At this stage, empirical evidence for a connection between cosmic ray flux and cloud cover are, at best, weak, and this is discussed in the IPCC AR4 (http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-7-1-3.html).
Doug Cotton
(IT Manager)
See reference to clouds herein: http://www.drroyspencer.com/2011/10/our-grl-response-to-dessler-takes-shape-and-the-evidence-keeps-mounting/
James Szabadics
Technical Development and R&D Manager, Plantation Timber Industry (logged in via email @technologist.com)
I think it is important that we try to better understand why global average temperature does not warm in lock step with CO2 concentration in the atmosphere and GCR/cloud mechanisms are an important part of that research. The IPCC AR4 did not have the results of the CERN CLOUD experiments to refer to.
Clouds are an important factor in the radiative budget of the planet and very difficult to model particularly if we don't understand all of the mechanisms for their variation.
Its very important…
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Michael J. I. Brown
(ARC Future Fellow and Senior Lecturer at Monash University)
While the IPCC didn't have the CERN CLOUD experiment results, the lead author of the CERN CLOUD paper has stated "At the moment, it actually says nothing about a possible cosmic-ray effect on clouds and climate, but it's a very important first step".
Also, empirical connections between observed cosmic ray flux and cloud remain weak. A clear connection has not been consistently observed by multiple research groups and the IPCC's summary remains valid.
The IPCC does not assume all the forcings are…
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Doug Cotton
(IT Manager)
But Michael, the very fact that significant variations have continued for periods around 20 years (such as in the 1940's and 1950's) proves that there are other significant factors (presumably natural ones) that are making a very significant contribution. What anthropogenic changes, for example, could have caused the sudden turn around of sea levels which started to decline recently and are now back to levels of two years ago? Just look at the plot and it's obvious this is a significant breakout…
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John Nicol
(logged in via Facebook)
What you are saying Michael about the results of the preliminary CERN experiment is true. It was never intended to show that cosmic rays have a significant effect on the production of clouds. However, Svensmark has been examining this hypothesis for abot 14 years and has some significant success in demonstrating that it could indeed be one of the main driers of climate - both warming and cooling. The interest in the CERN experiment is that it reproduces the POSSIBLE basis for the theoretical analysiis…
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Michael J. I. Brown
(ARC Future Fellow and Senior Lecturer at Monash University)
Svensmark has claimed that cosmic rays play a significant role in climate, but multiple research groups have yet to consistently observe an empirical link between clouds and climate (this is discussed in IPCC AR4). It is thus not well established science.
The original Svensmark theory is definitely interesting and worth pursuing. However, the CERN CLOUD experiment has yet to produce particles of the relevant size (as noted in the article above).
Even if the CERN CLOUD experiment produces particles of the relevant size, one then has to determine if this mode of cloud formation is actually significant. For example, there is a well established link between forest fires and cloud formation (pyrocumulus cloud) but this mode of cloud formation plays a relatively modest role in global climate.
James Szabadics
Technical Development and R&D Manager, Plantation Timber Industry (logged in via email @technologist.com)
Michael, I'm not sure you actually meant to say that the IPCC found no empirical link between climate and clouds. Maybe you meant to say no link between GCR and clouds but then there is no good data for earth albedo to make a definite call one way or the other?
I would imagine there is a definite link between clouds and precipitation?
How about the earths albedo and subsequent radiation budget at the earths surface to convert the incoming shortwave radiation to the necessary longwave IR for greenhouse effects.
How far did the IPCC look for links between cloudiness and climate exactly?
Peter Doidge
(Mr)
James, why don't you read the IPCC's reports? In particular, Chapter 3 of the Fourth Assessment Report, section 3.4.3 (p.275).
James Szabadics
Technical Development and R&D Manager, Plantation Timber Industry (logged in via email @technologist.com)
Peter, more to the point why dont we share what IPCC AR4 Chapter 3 3.4.3 actually says. I lifted the opening statements from that section below :
QUOTE
Clouds play an important role in regulating the flow of radiation at the top of the atmosphere and at the surface. They are also integral to the atmospheric hydrological cycle via their integral influence on the balance between radiative and latent heating. The response of cloud cover to increasing greenhouse gases currently represents the largest uncertainty in model predictions of climate sensitivity.
ENDEQUOTE
So you see that understanding the nature of cloud formation mechanisms is critical to getting the climate sensitivity to CO2 correct.
Doug Cotton
(IT Manager)
Well explained and somewhat reassuring that there may be no effect of cosmic rays on climate. There is still a nagging doubt created by the fact that there appears to be some possible correlation of climate which appears to lag variations in sunspot activity by about 20 years. Certainly sunspot activity was low at the time of the Little Ice Age and I'm sure we've all seen the first plot here: http://earth-climate.com/photo0.jpg and we know that short-term (11 to 13 year) sunspot cycles are controlled…
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Doug Cotton
(IT Manager)
The issue of clouds affecting climate is addressed in this paper http://www.drroyspencer.com/2011/10/our-grl-response-to-dessler-takes-shape-and-the-evidence-keeps-mounting/
"Dessler claims that changes in ocean temperature are way too large to be caused by clouds. Well, the year-to-year changes in Levitus global ocean heat content of the 0-700 m layer during the 2000-2010 satellite period of record yields a yearly standard deviation of 0.5 Watts per sq. meter for the energy required. In comparison…
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John C
(logged in via email @gmail.com)
This has to be the longest set of comments on an article in history. I might nominate it to Guiness.
Jane Rawson
(Editor, The Conversation)
it's a bit shorter now: there was a fairly nasty comment in there which I had to delete, and sadly (?) it had rather a lot of replies which got deleted along with it.
Mark Harrigan
Dr (logged in via email @tpg.com.au)
Salutory - thanks. The AGW debate gets heated at times. Mea Culpa.
Mark Harrigan
Dr (logged in via email @tpg.com.au)
The original premise of this article points out that the CERN results on cloud formation do nothing to overturn AGW and point out the web-based blogosphere isn't real science
"Such claims on the web are, therefore, perhaps hopeful at best and misinformation at worst. Linking these claims to the recent work at CERN does a great disservice to the interesting and important results from those researchers.
Taken in overall context, the impact of cosmic rays is not likely to have a large or significant…
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Mark Harrigan
Dr (logged in via email @tpg.com.au)
For those who are TRULY interested in learning more about the science of Climate Change there is a wonderful set of interactive lessons here http://www.pics.uvic.ca/insights/lesson1/player.html
Including a very clear video of a simple experiment that demonstrates the physical relaity of how CO2 absorbs heat energy.
Try it :)
Doug Cotton
(IT Manager)
No, that "simple experiment" does not prove that, when carbon dioxide absorbs energy, the end result is a (slight) warming of the whole Earth from one year to the next. After all, in any location it cools most nights and most winters, so what is the carbon dioxide doing in that location as night approaches, or in that hemisphere as winter approaches? And even the cumulative effect since January 2003 has not shown any net warming. Such experiments are for the gullible.
Mark Harrigan
Dr (logged in via email @tpg.com.au)
Doug, with respect, it shows conclusively that CO2 absorbs heat (long wave IR) and, by the way, does NOT re-emit by stimulated emission. That is what I said. I did not say it proves the end result is a warming of the earth.
There are abundant other experiments, satellite evidence and papers that establish that as a result of the CO2 absorption of long wave IR, the earth is warming. I understand you refuse to accept their validity - but the vast majority of the scientific community does.
Doug Cotton
(IT Manager)
That's what I said it did in the first line which reads "... when carbon dioxide absorbs energy ..."
By "energy" I mean thermal energy which, when it is in transit, is heat.
No. As I have explained on my website, the "abundant other experiments" prove that carbon dioxide is absorbing some IR radiation because the spectral lines for carbon dioxide are missing. Fullstop.
That is all they prove. You really don't think for yourself do you? Nor do all the others who, like yourself, fall into the trap of thinking this means the heat does not escape by another route after it warms the surface and the oceans. You have never addressed this point which I have made numerous times. This is the crux of the matter.
All this explanation is on my site and has been all along.
http://climate-change-theory.com
Good bye.
Mark Harrigan
Dr (logged in via email @tpg.com.au)
Your "web site" explanation has no credibility. See Occams razor. Goodbye to you too :)
Doug Cotton
(IT Manager)
You're welcome to believe in the credibility of the IPCC pseudo-physics and their cover-up as exposed at Climategate ...
"Explicit evidence of the manipulation of proxy records used in paleoclimate reconstructions, suppression of other viewpoints, manipulation of the IPCC process, and intimidation of journal editors were all evidence of serious breaches of ethics." Lindzen & Douglass
James Szabadics
Technical Development and R&D Manager, Plantation Timber Industry (logged in via email @technologist.com)
Mark,
the best explanation for the role of clouds in climate can be found here.
http://www.nasa.gov/images/content/57911main_Earth_Energy_Budget.jpg
You can see that clouds and aerosols play an important role on the left side such that a minor variation of cloud cover changes the quantity of solar incident radiation able to be radiated from the earth in the relevant IR wavelengths to warm the atmosphere via the action of GHG such as water vapour, carbon dioxide and methane etc.
The CERN CLOUD experiment does not set out to prove the link between GCR and variations of cloud but it does demonstrate that incident GCR plays a role in forming aerosols in the atmosphere. These aerosols will vary albedo and MAY play a role in seeding larger aerosols and clouds but this next link needs to be investigated and researched.
Mark Harrigan
Dr (logged in via email @tpg.com.au)
Thanks James - I am aware of the NASA link. I agree the science establishes that water vapour, clouds and aerosols have important roles to play and that the CERN experiment established that there is at least a role for GCR in the first stages of nucleation for clouds etc.
However water vapour is generally accepted to have an overamplifying effect on warming. The impact of clouds works both ways and aerosols provide some cooling through increased albedo.
But, as the article says, "Taken in overall context, the impact of cosmic rays is not likely to have a large or significant influence on future climate change either."
James Szabadics
Technical Development and R&D Manager, Plantation Timber Industry (logged in via email @technologist.com)
Mark,
I think that the role of cosmic rays in past and future climate change is yet to be properly determined. We simply cannot say that it is unlikely to be significant until we understand what role it actually does play in cloud cover and aerosol/albedo variations.
Through research and better understanding of GCR effects on cloud and albedo we can correctly determine the sensitivity of atmospheric temperature to CO2 concentration. Only once we understand and quantify the various factors in…
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Mark Harrigan
Dr (logged in via email @tpg.com.au)
With due respect James you are grasping at straws and getting ahead of the science. Your suggestion is also quite at odds with the scientific conclusion of this article and indeed James kirby himself of CERN who said
"At the moment, it actually says nothing about a possible cosmic-ray effect on clouds and climate, but it's a very important first step"
In reality, the CERN experiment only tests that cosmic rays have a role in triggering aerosol (liquid droplet) formation.
For cosmic rays to be…
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James Szabadics
Technical Development and R&D Manager, Plantation Timber Industry (logged in via email @technologist.com)
Mark,
you also stated that GCR flux has been flat. I think that what you really mean is that over a 50 year period GCR flux has no trend. It does have decade scale trends and changes.
You can see the significant variability of GCR here
http://www.puk.ac.za/opencms/export/PUK/html/fakulteite/natuur/nm_data/data/SRU_Graph.jpg
Hermanus has the longest record. If you draw a line through the Hermanus proton flux data at around 77 on the Y axis and treat it as a cooling threshold for GCR flux…
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Mark Harrigan
Dr (logged in via email @tpg.com.au)
James - I did read your post but, on my interretation of your replies, you have falied to understand the logic of my 4 numbered points. Regardless of what comes from the CERN data - precisely because of what we DO know about GCR trends - they CANNOT be the source of AGW in the last 40-50 years. The data you link to makes that clear.
There must be an explanation of the warming trend since the 70's - the best science shows it is warming due to increased CO2 emissions from humans.
Whilst I agree…
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James Szabadics
Technical Development and R&D Manager, Plantation Timber Industry (logged in via email @technologist.com)
Mark,
perhaps you didnt read my post - I said that the role of cosmic rays in climate change has not been determined. Because it has not been determined you cannot state that is has an insignificant role. We simply dont have the data to support or debunk it yet. CERN merely proved incident GCR does form aerosol particles which means we have to investigate the theory further. If CERN found GCR do not form aerosols in the atmosphere the theory would be dead - but the opposite happened. That doesnt…
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Doug Cotton
(IT Manager)
John Nicol has made good points very much in keeping with what I am also pointing out.
The conventional arguments can be broken down into three categories ...
(1) Verbal discussion based on the science that carbon dioxide captures and re-emits IR radiation some of which returns and warms the Earth (land or oceans) and so heat is supposedly trapped.
(2) Net TOA radiative flux has been measured as (slightly) on the downward (positive) side during periods of warming. This is supposedly backed…
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Toby James
retired physicist (logged in via email @yahoo.com)
Hear hear!
There is no real-world science in support of the AGW hypothesis. But there is some interesting real science underway of which the recent results from CERN are a part.
Michael J. I. Brown
(ARC Future Fellow and Senior Lecturer at Monash University)
"There is no real-world science in support of the AGW hypothesis" except for rising CO2 levels, the spectrum of the Earth measured from satellites, rising sea levels over the past century, rising global temperatures over the past century and Arctic ice retreat.
The blogsphere and the real-world are very different things when it comes to science.
Doug Cotton
(IT Manager)
The AGW assumption that more carbon dioxide causes more warming is not proven by the fact that carbon dioxide increased and the world warmed. Lots of other things also increased, like the number of underground nuclear tests which could have caused warming by releasing core heat more readily by damaging the crust and reducing its insulation effect. And of course natural causes such as those that caused the Roman and Medieval warming could also have re-appeared. Regarding other points, I have explained several times why missing spectral frequencies certainly do show that carbon dioxide levels have increased, but they do not lead to a conclusion that warming must have been the result of such increases.
Michael J. I. Brown
(ARC Future Fellow and Senior Lecturer at Monash University)
Doug Cotton suggests two possible proofs for anthropogenic greenhouse warming.
Doug Cotton's first test isn't valid, as climate models do not predict a lockstep link between CO2 levels and temperature rise. For a start, there is natural variability in climate (particularly on scales of =).
Doug Cotton
(IT Manager)
What would be a suitable proof? Well for a start we'd have to see a much closer tracking of temperature data with carbon dioxide levels (both short and long term) than exists in any past data. We'd need to see experiments such as Nahle's overturned with contrary results. We'd need to see the accuracy of models improved about tenfold so that they actually could predict whether warming or cooling should be happening.
No amount of data relating to missing spectral lines would convince us, because…
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John Nicol
(logged in via Facebook)
Michael, While I respect your approach to the global warming debate, I am also sure that you are aware that the evidence of rising CO2 levels from both measurments and calculations of fuel use has nothing to do with the claims that CO2 causes global warming. It is only relevant if it has been shown that increases in CO2 does in fact cause this effect. There are no publications that I am aware of which substantiate this. Neither do rising global temperatures, Arctic ice melt or rising sea levels…
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Michael J. I. Brown
(ARC Future Fellow and Senior Lecturer at Monash University)
What would be a suitable proof of anthropogenic global warming for the "sceptics"? Can they nominate a specific experimental test that would satisfy them? Clearly the current wealth of data is insufficient.
One can play the game of arguing the evidence is insufficient with almost any theory in science, including the well established ones.
For example, one could argue that while general relativity accurately predicts the deflection of light by the Sun, the deflection of light is not a "direct" measure of the curvature of space-time and thus there is no "real-world" evidence for general relativity. Of course, most scientists would view this argument as absurd given the number of predictions general relativity makes that have been verified with observation. However, in the blogsphere such absurd arguments seem to be the norm.
Toby James
retired physicist (logged in via email @yahoo.com)
Right Michael. That's what I mean - the absence of real-world science. That is not the kind of science that gives us mobile phones and radar at the airport.
John Nicol
(logged in via Facebook)
I have just written a similar comment on the post regarding the reality of the green house effect by Karl Braganza. I think it is appropriate for me to copy it here.
Having spent some considerable time discussing the basis for the assumptions made regarding warming by increased atmospheric carbon dioxide with members of the CSIRO Climate Group and attempting to learn more about the basis of the green house effect from people such as Andy Pitman and Will Steffen without being provided with any…
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Michael J. I. Brown
(ARC Future Fellow and Senior Lecturer at Monash University)
I believe John Nicol is chairman of the "sceptic" Australian Climate Science Coalition, that includes Bob Carter, Ian Plimer and other prominent sceptics.
John Nicol should be aware that Tyndall and Arrhenius are merely starting points for the topic of the CO2 and its impact on the transmission of light through the atmosphere (and are cited accordingly). To claim otherwise is to misinterpret the literature.
Even Raymond Pierrehumbert's short introduction to infrared radiation and planetary temperature demonstrates that the topic has moved well beyond 19th century physics (http://geosci.uchicago.edu/~rtp1/papers/PhysTodayRT2011.pdf).
Sophisticated models of CO2's impact on the transmission of infrared light through the atmosphere are available, and these can be cross checked with measurements. For example, models of the transmission of light through the atmosphere can be cross checked against measurements of the spectrum of the Sun.
John Nicol
(logged in via Facebook)
Yes Michael I am that chairman but I can not see how that is relevant at all in a scientific discussion. I had once been concerned about the claimed warming and had often stated that if there was a problem then we should cut the use of fuel and deal with it. However, when I retired I decided to take up the matter as a hobby and to follow my long term research interests in the absorption and emission processes as well as collision energy transfer in gases. I went to the experts such as CSIRO and…
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Michael J. I. Brown
(ARC Future Fellow and Senior Lecturer at Monash University)
If John Nicol believes mainstream science has it wrong when it comes to the transmission of light through the atmosphere, then he should publish a peer reviewed science article on the topic.
The scientific community readily accepts robust paradigm changing evidence, as demonstrated by this year's Nobel Prize for Physics.
There is a wealth of data which John Nicol can compare his model to. He could compare his model to the transmission of light through the atmosphere measured using the solar spectrum. He could also compare his model to the infrared spectrum of the Earth (as Pierrehumbert does in his introduction to the topic).
Comparisons of models with relevant data are essential for good science. The absence of such comparisons in John Nicol's online essays greatly diminishes their standing.
John Nicol
(logged in via Facebook)
Michael,
Thank you for your comments. I hope you were able to read the comment I have just made right through.
As I mentioned above, I have tried desparately to obtain the type of article to which you refer with which to compare my own calculations but no one who is working in that field of climatology in Australia has been able to provide with such a article. Penny Whetton, head of the CSIRO climate Group can only refer me to very general reports such as Climate Change in Australia 2007 which…
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Michael J. I. Brown
(ARC Future Fellow and Senior Lecturer at Monash University)
The relevant data on atmospheric transmission of infrared light is not hard to find.
Pierrehumbert's article includes the AIRS satellite spectrum of the Earth. A google search for "AIRS spectrum Earth" reveals a number of articles on this particular topic.
Similarly, a google search for "Solar spectrum atmospheric transmission" reveals a number of articles and websites on the topic. Using google scholar reveals academic articles while searching for images reveals plots, including some in academic…
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Doug Cotton
(IT Manager)
Michael - this is still just so much waffle. Mistakes have been made in the past in published papers, and are still being made.
Think man, think for yourself! Address the actual issues that John and I have raised.
The very scientists who pushed this hypothesis through the IPCC cannot answer for their actions - cannot explain the points John raised with them. The Chinese sceptics are right about the theory being wrong, even if wrong about the US motives. (See The Sydney Morning Herald and…
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John Nicol
(logged in via Facebook)
Yes Michael, I have responded to your comment to me elsewhere but just want to acknowledge your suggestions here. I am pretty familiar with the spectra and with the HITRAN data base as well and have followed your guide to AIRS. There was nothing new there and `no attempt to analyse the data which is similar to a lot of data that is on the net. But thank you anyway. Cheers, John Nicol
Michael J. I. Brown
(ARC Future Fellow and Senior Lecturer at Monash University)
If John Nicol is familiar with the data, why doesn't he do a quantitative comparison of the predictions of his model with this data?
Some plots comparing his model to the measured transmission of the Earth's atmosphere as a function of wavelength and the infrared spectrum of the Earth would be good places to start.
John Nicol
(logged in via Facebook)
Michael,
(From your earlier comment may I say, yes I am very well aware of the details of the characteristic spectrum of the earth - the BB spectrum and the satellite determination of radiation frequencies/wavelngths from all of the green house gases which are responsible in the upper troposphere for the cooling of the planet - as partially described by Pierrehumbert, but without any really quantitative descriptions. You also mention comparison of models with relevant data. I have not yet been…
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Michael J. I. Brown
(ARC Future Fellow and Senior Lecturer at Monash University)
If John Nicol believes mainstream science has things grossly wrong, he should use his model to make predictions and compare it with relevant data. That is how science is advanced.
In my previous comments, I have shown one can start to find the literature and data relatively easily with google. A more thorough search will reveal more.
One should do a thorough literature review prior to publication, not afterwards. This is one thing that distinguishes real science from many self published online essays. In the case of the latter, opinion is ventured without understanding the relevant theory and comparing to the relevant data.
To illustrate how easy the data is to find, I was able to find the AIRS data cunningly hidden on the AIRS website (http://airs.jpl.nasa.gov/data/get_AIRS_data/). The AIRS website also lists the relevant peer reviewed journal articles.
Peter Doidge
(Mr)
John Nicol, what is the basis for your claim that, in the Pierrehumbert article, "...the value for the Einstein A coefficient of the lines forming the main CO2 bands is wrong by a factor of 100"?
John Nicol
(logged in via Facebook)
The A coefficient is generally accepted as being in the region of 10^5 s^-1 whereas Pierrehumbert states it as 10^3 and even suggests components with coefficients as low as milliseconds, metastable. The time between collisions which he more correctly states as being "much lower than 10^-7" I think, has to be nearer 10^9. Either way a transition with a millisecond lifetime could not make any significant contribution to the radiation transfer process - I will have to add "I believe" of course!
John Nicol
Peter Doidge
(Mr)
John Nicol: I do not understand your reasoning concerning stratospheric cooling, and the supposed link to GHGs: "So this [cooling] again is not a signature of green house warming". So, if the observed cooling is not due to GHGs, what then causes it?
Doug Cotton
(IT Manager)
Michael. There are two issues arising from the Pierrehumbert article.
The first is the assumption that the ground below the atmosphere emits as a perfect blackbody. It simply does not happen that all heat from the ground (and oceans) enters the atmosphere by way of radiation. If that were the case we would never see the observed (near) equilibrium between surface and the lowest 1mm of the atmosphere. There have to be processes of evaporation and diffusion (molecular collision) which also transfer…
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Peter Doidge
(Mr)
John Nicol, I am surprised by your claim that "Callendar, Hansen, Ramanathan, Kiehl and Trenberth simply follow the arguments of Arrhenius without expressing any more relevant physical theory or without reference to modern experiments". This is simply not true. In the 1940s and 1950s, a lot of work was carried out to compare the measured and calculated absorptions of infra-red active gases. Callendar himself was involved in some of this. These newer absorption data were used in numerical computations…
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