Climate Physics 101


Climate change: news and comments

Sorry folks, cosmic rays really are in charge


On this blog and others, most comments about my previous post “Yet another trick of cosmic rays” have been friendly. Thank you. But some people still want to dismiss all the meticulous experimental, observational and theoretical work of Henrik Svensmark and his colleagues in the Danish National Space Institute by saying there is simply no link between cosmic rays and the climate.

Having written two books on the subject, and still engaged with it, I could in rebuttal flood this post with evidence of many kinds, on time scales from days to millennia or longer. I’ll content myself with just one pair of graphs spanning 50 years. They’re from a 2007 report by Svensmark and the Institute’s director, Eigil Friis-Christensen, and they’re based on a European Space Agency project called ISAC. The carbon dioxide boys and girls would die for a match of cause and effect of this quality.

Cosmic ray intensity is in red and upside down, so that 1991 was a minimum, not a maximum. Fewer cosmic rays mean a warmer world, and the cosmic rays vary with the solar cycle. The blue curve shows the global mean temperature of the mid-troposphere as measured with balloons and collated by the UK Met Office (HadAT2).

In the upper panel the temperatures roughly follow the solar cycle. The match is much better when well-known effects of other natural disturbances (El Niño, North Atlantic Oscillation, big volcanoes) are removed, together with an upward trend of 0.14 deg. C per decade. The trend may be partly due to man-made greenhouse gases, but the magnitude of their contribution is debatable.

From 2000 to 2011 mid-tropospheric temperatures have remained pretty level, like those of the surface, despite the continuing increase in the gases – in “flat” contradiction to the warming predicted by the Intergovernmental Panel on Climate Change. Meanwhile the Sun is lazy, cosmic ray counts are high and the oceans are cooling.


Svensmark, H. and Friis-Christensen, E., “Reply to Lockwood and Fröhlich The persistent role of the Sun in climate forcing”, Danish National Space Center Scientific Report 3/2007.

Yet another trick of cosmic rays


Climate Change: News and Comments

In the climax to the Danes’ experiments, cloud seeds flout the theories

Near to the end of the story that starts with stars exploding in the Galaxy and ends with extra clouds gathering, a small but important paragraph was missing till now. From experiments in Copenhagen reported in 2006 and reconfirmed in 2011 in Aarhus and Geneva (CERN, CLOUD), cosmic rays coming from old supernovas can indeed make molecular clusters a few millionths of a millimetre wide, floating in the air. But can these aerosols really grow nearly a million times in mass to be large enough to become “cloud condensation nuclei” on which water droplets can form – as required by Henrik Svensmark’s cosmic theory of climate change?

Opponents pointed out that theoretical models said No, the growth of additional aerosols would be blocked by a resulting shortage of condensable gases like sulphuric acid in the atmosphere.

Not for the first time, an unexpected trick that Mother Nature had up her sleeve is revealed by experiment. The discovery is elegantly explained by a new way in which sulphuric acid forms in the atmosphere, as announced in a paper by Svensmark and two of his colleagues in Denmark’s National Space Institute in Copenhagen, Martin Enghoff and Jens Olaf Pepke Pedersen. They have submitted it to Physical Review Letters. A preprint is available on arXiv here

Svensmark, Enghoff and Pepke Pedersen

A brief history. Last year’s attempts to dismiss the Aarhus and CERN results as inconsequential for climate change didn’t dismay the Danes. They knew there was something wrong with the current understanding because they had observational support for the whole chain from solar activity to cosmic rays to aerosols to clouds in the real atmosphere (Svensmark, Bondo and Svensmark 2009). In order to dig into the physics, they decided to rebuild, in the basement of the Space Institute, the 8 cubic metre experimental chamber SKYII which six years ago was used as the CLOUD prototype chamber at CERN,

In the limelight of the atmospheric drama, sulphuric acid is one of the commonest of trace gases and very important for both the formation and the growth of aerosols. When the Sun rises in the morning, its ultraviolet rays convert sulphur dioxide, ozone and water vapour in the air into sulphuric acid molecules. These are continuously lost as they club together with further water and a little ammonia into very small molecular clusters. Nevertheless, the concentration of sulphuric acid rises to a peak and then diminishes as the Sun goes down in the evening.

A clue that something more is going on comes from the persistence all through the night of sulphuric acid at about 10 per cent of the daytime maximum. If these molecules too are continuously lost, they must be replenished by a chemical reaction that doesn’t need ultraviolet light.

What did the new experiment called SKY2 show? Without going into technical details that you’ll find in the paper, let’s just say that the primary result flatly contradicts the theoretical prediction that the infant aerosols couldn’t grow up into cloud condensation nuclei. Here’s a figure from the paper.

Molecular clusters grow over time, in the SKY2 experiment in Copenhagen. The horizontal axis is scaled in nanometres (millionths of a millimetre) and each blue point shows the relative number of clusters of that size before and after the experimental runs. Anything over 1.0 means that growth has continued. In contrast, the red points illustrate a pessimistic prediction of previous theories, that growth should cease when the size passes 50 nanometres. On the other hand, the black curve running through the blue points shows what is to be expected if there is a continual supply of sulphuric acid. The persistent growth of clusters occurs only in the presence of gamma rays that simulate cosmic rays and set electrons free to influence the chemistry.

So what’s the explanation? What new pathway supplies the sulphuric acid needed to keep the growth going? The Danes recall a suggestion in their 2006 SKY report that electrons can act like catalysts, being used over and over again to promote chemical action. In the new paper they say: A possible explanation could be that the charged clusters are producing additional [sulphuric acid] molecules from reactions involving negative ion chemistry of [ozone, sulphur dioxide and water], where a negative ion can be reused in a catalytic production of several [sulphuric acid molecules].

Depending on the concentrations of trace gases, several may mean dozens. And where do the electrons come from? They are liberated by cosmic rays raining down by night as well as by day. If the results of the experiment and these ideas are confirmed, there’s an amazing pay-off. The cosmic rays help to make the extra sulphuric acid that allows (1) a number of additional aerosols to form and (2) a larger number of aerosols to grow into cloud condensation nuclei. Without this second effect the aerosols would grow slowly and most of the extra aerosols would be lost before becoming large enough to seed clouds.

That ions liberated by cosmic rays promote a second pathway for forming sulphuric acid was already known from an experiment performed in Copenhagen in a collaboration with the University of Copenhagen and the Technical University of Tokyo (see the Enghoff et al. reference below). Depending on whether the sulphuric acid comes from ultraviolet action or is ion-induced, it has different signatures in the relative abundances of isotopes of sulphur. What’s more, the number of molecules made by the ion route greatly surpassed the number of ions available, again implying reuse of the electrons in a catalytic fashion.

To summarize the latest paper, the Svensmark, Enghoff and Pepke Pedersen abstract reads:

In experiments where ultraviolet light produces aerosols from trace amounts of ozone, sulphur dioxide, and water vapour, the number of additional small particles produced by ionization by gamma sources all grow up to diameters larger than 50 nm, appropriate for cloud condensation nuclei. This result contradicts both ion-free control experiments and also theoretical models that predict a decline in the response of larger particles due to an insufficiency of condensable gases (which leads to slower growth) and to larger losses by coagulation between the particles. This unpredicted experimental finding points to a process not included in current theoretical models, possibly an ion-induced formation of sulphuric acid in small clusters.

Scandals of a political character engulf climate physics these days, but future historians may shake their heads more sadly over scientific negligence. Isn’t it amazing that such a fundamental activity of sulphuric acid, going on over your head right now, has passed unnoticed since 1875 when cloud seeding was discovered, since 1996 when Svensmark found the link between cosmic rays and cloud cover, and since 2006 when the Danes suggested the catalytic role of electrons? Perhaps the experts were confused by the ever-present dislike of the role of the Sun in climate change.

So Svensmark and the small team in Copenhagen have had nearly all of the breakthroughs to themselves. And the chain of experimental and observational evidence is now much more secure:

Supernova remnants cosmic rays solar modulation of cosmic rays variations in cluster and sulphuric acid production variation in cloud condensation nuclei variation in low cloud formation variation in climate.

Svensmark won’t comment publicly on the new paper until it’s accepted for publication. But I can report that, in conversation, he sounds like a man who has reached the end of a very long trek in defiance of continual opposition and mockery.


Henrik Svensmark, Martin B. Enghoff and Jens Olaf Pepke Pedersen, “Response of Cloud Condensation Nuclei (> 50 nm) to changes in ion-nucleation”, submitted for publication 2012. Preprint available at

H. Svensmark, T. Bondo and J. Svensmark, “Cosmic ray decreases affect atmospheric aerosols and clouds”, Geophysical Research Letters, 36, L15101, 2009

Henrik Svensmark, Jens Olaf Pepke Pedersen, Nigel Marsh, Martin Enghoff and Ulrik Uggerhøj, ‘Experimental Evidence for the Role of Ions in Particle Nucleation under Atmospheric Conditions’, Proceedings of the Royal Society A, Vol. 463, pp. 385–96, 2007 (online release 2006). This was the original SKY experiment in a basement in Copenhagen.

M. B. Enghoff, N. Bork, S. Hattori, C. Meusinger, M. Nakagawa, J. O. P. Pedersen, S. Danielache, Y. Ueno, M. S. Johnson, N. Yoshida, and H. Svensmark, “An isotope view on ionising radiation as a source of sulphuric acid”, Atmos. Chem. Phys. Discuss., 12, 5039–5064, 2012. See

Some relevant items on this blog

Aarhus experiment

CERN CLOUD experiment

Observational evidence of aerosol growth

Summary of Svensmark’s theory

Cosmic rays sank the Titanic


Climate Change: News and Comments

Full steam ahead for the real story of 20th Century warming

Although It seems a strange thing to celebrate, the Titanic Festival in Belfast, where the ship was built, will very soon mark the 100th anniversary of the liner’s foundering on 15 April 1912 after hitting a south-wandering iceberg, with the loss of a multitude of passengers and crew.

Comparing the £100-million Titanic complex newly built in Belfast with the Guggenheim Museum in Bilbao, the travel writer Simon Calder has commented, “There is a great shipbuilding heritage, it is a divided city, but the Guggenheim is great on the outside but rubbish on the inside – unlike the Titanic building.”

What’s more, James Cameron’s movie “Titanic” has been remastered in 3D for the centenary.

Time then for me to dig out some slides that I’ve used off and on in lectures since 1999 as an illustration of Henrik Svensmark’s cosmic rays in action, controlling our climate. But first, just to show that I’m not being kooky, here’s a graph from a 2000 paper by E. N. Lawrence of the UK Meteorological Office. “The Titanic disaster – a meteorologist’s perspective” related iceberg abundance at low latitudes to a scarcity of sunspots.

by E.N. Lawrence

And Steven Goddard recalls a much older article, from the Chicago Tribune in 1923, that also linked icebergs with sunspots

The notion that the Sun is dimmer when there are few sunspots goes right back to William Herschel at the beginning of the 19th Century. The trouble is that the variations in solar brightness, as measured by satellites, are too small to explain the strong influence of the Sun on climate as recorded over thousands of years, and continuing into the 21st Century. That’s where Svensmark’s discovery of 16 years ago comes in, with the amplifier. Cosmic rays coming from the Galaxy are more intense when there are fewer sunspots and they increase the global cloud cover, so cooling the world.

Some preliminary comments before showing my own slides about cosmic rays and the fate of Titanic. Of course the disaster also involved several elements of shameful seamanship, but the fact remains that large icebergs abounded much further south than usual in the spring of 1912. Secondly, I prepared the slides so long ago that I can’t recall the data sources. If challenged, I expect I could dig them out, and I do remember that the picture is from the Illustrated London News.

There was no direct recording of cosmic ray variations in those days. Indeed. Victor Hess was busy discovering them at that very time. So we have to make do with the geomagnetic activity index (called aa in the second slide) as an inverse indicator of cosmic ray influx, and with the counts of beryllium-10 and carbon-14, which are made by cosmic rays. Otherwise the slides should speak for themselves.

by Nigel Calder

by Nigel Calder

The theme music of Cameron’s film “Titanic” is entitled “Full Steam Ahead”. Although the ship came to an abrupt halt, the same has not happened to Svensmark’s theory. As plenty of other posts on this blog will show you, its bow wave keeps sweeping aside the attempts to falsify it. And fresh energy builds up more and more speed as all the pieces of the hypothesis fall into place, from quantum chemistry to the shape of the Milky Way Galaxy.

It’s a truly titanic idea, threatening disaster for the multitude who ignore the natural drivers of climate change, and shame for the misguided folk on the bridge who peer at computer screens instead of looking out of the window.


Simon Calder quoted:

E.N. Lawrence, Weather (Roy. Met. Soc.), Vol. 55, March 2000.

See also this from NOAA

The Sun and auroras for beginners


Pick of the pics

Our Explosive Sun by Pål Brekke

In “Our Explosive Sun”, the picture has this caption. “A unique image of the planets close to the Sun observed with the LASCO telescope on SOHO. An occulting disk inside the telescope blocks the bright light from the solar disk creating an artificial solar eclipse. Mercury, Venus, Jupiter, Saturn, and the Pleiades are visible. Just outside the occulting disk one can see enormous ejections of gas from the hidden Sun. The horizontal streaks from the planets are artifacts from the digital camera (ESA/NASA).”

It’s one of my favourite images from the Space Age. The Large Angle and Spectrometric Coronagraph (LASCO) took it on 15 May 2000. Four planets and the Pleiades star cluster were almost in line with the Sun – which chose this theatrical moment to blast off a huge puff of gas in a coronal mass ejection (CME). So I’m not surprised to find the picture in Our Explosive Sun by Pål Brekke, a colourful book that’s just been published by Springer.

Pål Brekke (NRS)

Pål (pronounced Paul) is a Norwegian solar physicist who worked in the SOHO team for more than a decade, latterly as Deputy Project Scientist. We’ve known each other well from the time when I was writing a lot for the European Space Agency. Pål’s now a Senior Advisor at the Norwegian Space Centre.

Let’s be clear that Our Explosive Sun is a book for beginners, be they amateur astronomers, aurora watchers, high school students, or interested non-experts of any description. There’s plenty of elementary information about our mother star and the Solar System, and about how to observe the Sun safely or photograph the Northern Lights. Making the book distinctive are a mass of extraordinarily vivid and up to date illustrations, plus the occasional insights you get only from a true expert.

For example, in warning of the dangers that solar explosions will pose to astronauts flying to the Moon or Mars, Pål reminds us that the lunar flights of Apollos 16 and 17, in April and December 1972, were lucky to miss a big burst of deadly solar protons in August of that year. And in explaining the distances of stars, he notes that in about 40 years time an astronomer with a supertelescope on a planet in the Pleiades star cluster might in principle see Galileo turning his own telescope on the Pleaides for the first time, from a distance of 440 light-years.

It’s a pity perhaps that Pål doesn’t mention cosmic rays, which provide one of the great markers of solar variations both currently and in the past. And his remarks on solar activity and climate change are brief and rather cautious, e.g.: One thousand years ago, it was warmer on Greenland than today. … Human-driven climate change will work in addition to natural climate variability mainly caused by the Sun.


Pål Brekke, Our Explosive Sun: A Visual Feast of Our Source of Light and Life, Springer 2012. [Hardcover]

Amazon UK:

Editors’ personal opinions


Climate Change – News and Comments

Nature muddies the water

As a science writer I’m well used to picking my way through the minefield of embargoes on papers not yet published. I know, too, of possible risks to scientists as well as journalists, when quoting from preprints or even reporting results presented at a conference. Publication can be cancelled.

You’d expect clear guidance from leading journals on that subject. How bewildering then, to read an editorial “Scientific climate” in today’s Nature (vol. 478, p. 428). It’s on the subject of the Berkeley Earth / Richard Muller furore noted in my recent posts. The editorial’s sub-heading is:

Results confirming climate change are welcome, even when released before peer review.

… Where “climate change” is to be understood, I suppose, as “catastrophic manmade global warming”. Other points from the editorial are, as I construe them:

  • The welcome is the stronger because the Muller results can be used against the Republicans in the USA.
  • But Muller really should not have publicised his work as he did.
  • Muller is wrong to claim that Science and Nature forbid the discussion of unpublished results – Nature only opposes pre-publicity.
  • All that said, it was fine for physicists to give pre-publicity to apparent evidence of neutrinos travelling faster than light.

What on earth does all that mean, to scientists and journalists who are just trying to tell their stories promptly? Here are three extracts from Nature’s instructions to authors concerning embargoes, which can be seen in full here

Material submitted to Nature journals must not be discussed with the media, except in the case of accepted contributions, which can be discussed with the media no more than a week before the publication date under our embargo conditions. We reserve the right to halt the consideration or publication of a paper if this condition is broken.”

The benefits of peer review as a means of giving journalists confidence in new work published in journals are self-evident. Premature release to the media denies journalists that confidence. It also removes journalists’ ability to obtain informed reactions about the work from independent researchers in the field.”

… communicate with other researchers as much as you wish, whether on a recognised community preprint server, on Nature Precedings, by discussion at scientific meetings (publication of abstracts in conference proceedings is allowed), in an academic thesis, or by online collaborative sites such as wikis; but do not encourage premature publication by discussion with the press (beyond a formal presentation, if at a conference).”

What the new editorial means, in my opinion, is that the politicisation of science has now penetrated right through to the workaday rituals of publication. On no account must you publicise your new work prematurely, unless you do it to bash the climate sceptics or the Republican Party or supporters of Special Relativity or anyone else the editors happen to dislike today. In that case they’ll forgive you.

Hoodwinked by Berkeley Earth


Climate Change – Notes and Comments

Propaganda Tito style

My previous post was too polite about Berkeley Earth. I’d not figured out Richard Muller’s game. The mainstream media have have portrayed him as a repentant climate sceptic who has wonderful new evidence confirming man-made global warming. To see how the story is playing, look for Richard Muller Berkeley on Google News (139 reports and counting).

Normally I try to stick to the science, without being naïve about the politics. Posted earlier on this blog is the text of a talk I gave called “Global Warming is Just Propaganda”, which you’ll find here



It compares the behaviour of the warmists with the tradecraft of propaganda during the Second World War. And the latest bout from Berkeley and the media reminds me, belatedly, of a manipulation of British propaganda in the Balkans in the early 1940s. For global warming read Stalinism and (at the risk of grossly overstating his importance) for Richard Muller read Tito.

Hoodwinking Churchill: Tito’s Great Confidence Trick, by the TV producer and military historian Peter Batty, was published earlier this year. Helped by a Communist mole filtering messages in the British team in Cairo, Tito fooled the West into thinking that he was the hero of the fight against the Italian and German forces in Yugoslavia. In fact he was subverting other guerrilla bands, doing deals with the Germans, and keeping his forces safe for a postwar Communist takeover of Yugoslavia. As Batty relates, Tito secured his 35-year dictatorship by butchering the non-Communist guerrillas who had been the real fighters in the occupied Balkans.

When Richard Muller, leader of the Berkeley Earth Surface Temperatures (BEST) project, gave testimony to the US Congress back in March, he called for the creation of an ARPA-like agency for climate issues. ARPA, more correctly nowadays called DARPA, is the Defense Advanced Research Projects Agency, a mighty organization with a $3 billion budget. Climate ARPA (CARPA?) might offer a promising niche for a 67-year-old astrophysicist.

But if that’s the aim, catastrophic man-made global warming must stay high on the political agenda. How better to go about making sure about that than to call yourself a sceptic, just as Tito pretended to be on Winston Churchill’s side. When the time came to show himself in his true colours Tito was celebrated in the Communist world. Similarly Muller has become an instant hero for the warmists.

Scientifically grotesque was the blurring in the Berkeley press release, as well as in the media, of the meaning of Muller’s main graph, shown in my previous post. Invited to comment by New Scientist, I said:

What do they mean by ‘global warming is real’? The graph of global land temperature changes associated with BEST’s announcement neatly confirms by their independent method that the warming stopped about 15 years ago. The Sun’s recent laziness has apparently cancelled any effect of ever-increasing man-made greenhouse gases.”

The interviewer commented:

I take your point about the reduced warming trend over the last 15 years, but this study is focused on the long-term warming trend which covers a century. How do you account for this long-term warming trend?”

My reply (which wasn’t reported by New Scientist) was:

Increased activity of the Sun, of course, from 1950 to the early 1990s as signalled most strikingly by the decline in ionizing cosmic rays at the Earth’s surface. See the red curve (ion chamber) in the attached figure.”

This is a coloured version of a graph in Henrik Svensmark, Physical Review Letters, 81, 5027-30,1998.

The message about Muller in the media, that “the science is settled (again)”, is completely at odds with the evidence.


Hoodwinking Churchill: Tito’s Great Confidence Trick, by Peter Batty, Shepheard Walwyn (London) 2011.

The long pause in warming confirmed


Climate Change – News and Comments

Nice research, curious rhetoric

Just dis-embargoed at noon PST (8 pm BST) on 20 October are a press release and associated papers from the Berkeley Earth Surface Temperatures (BEST) project. A team led by Richard A. Muller has been asking whether the histories of land surface temperatures from the likes of NOAA, NASA and the Hadley Centre are to be trusted. Clever statistics glean and process raw data from 39,000 weather stations world wide – more than five times as many as used by other analysts.

The short answer is that the other histories are broadly validated, as seen in this graph from one of the new papers.

If your eye can trace the black line of the BEST study, based on a random selection of weather stations, you’ll see that the average temperatures of the land correspond quite well with the other series.

What’s very odd is the rhetoric of the press release. It begins:

Global warming is real, according to a major study released today. Despite issues raised by climate change skeptics, the Berkeley Earth Surface Temperature study finds reliable evidence of a rise in the average world land temperature of approximately 1°C since the mid-1950s.

Global warming real? Not recently, folks. The black curve in the graph confirms what experts have known for years, that warming stopped in the mid-1990s, when the Sun was switching from a manic to a depressive phase.

Elsewhere the press release first begs the question by calling the past 50 years “the period during which the human effect on temperatures is discernible” and then contradicts this by saying, What Berkeley Earth has not done is make an independent assessment of how much of the observed warming is due to human actions, Richard Muller acknowledged.”

Let me say there is interesting stuff in the material released today, particularly in the paper on Decadal Variations, tracing links with El Niño and other regional temperature oscillations” — a subject I may return to when I have more time.

It hasn’t escaped my attention that BEST is today gunning mainly for Anthony Watts and his Surface Stations project in the USA, but he’s well capable of answering for himself. See

Added 21 October: See this rather uneasy comment from Judith Curry, a member of the Berkeley team

And later: New Scientist quotes me saying something similar to what’s above – followed of course by the usual grossly biased and poorly informed attempt at a put-down


The BEST home page, with downloadable press release and papers, is here

The graph shown above is Fig. 1 in “Decadal Variations in the Global Atmospheric Land Temperatures,” Richard A. Muller et al., unpublished


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