Climate Physics 101


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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.


CERN experiment confirms cosmic ray action


Climate Change – News and Comments

The global warmists’ dam breaks

A graph they'd prefer you not to notice. Tucked away near the end of online supplementary material, and omitted from the printed CLOUD paper in Nature, it clearly shows how cosmic rays promote the formation of clusters of molecules (“particles”) that in the real atmosphere can grow and seed clouds. In an early-morning experimental run at CERN, starting at 03.45, ultraviolet light began making sulphuric acid molecules in the chamber, while a strong electric field cleansed the air of ions. It also tended to remove molecular clusters made in the neutral environment (n) but some of these accumulated at a low rate. As soon as the electric field was switched off at 04.33, natural cosmic rays (gcr) raining down through the roof of the experimental hall in Geneva helped to build clusters at a higher rate. How do we know they were contributing? Because when, at 04.58, CLOUD simulated stronger cosmic rays with a beam of charged pion particles (ch) from the accelerator, the rate of cluster production became faster still. The various colours are for clusters of different diameters (in nanometres) as recorded by various instruments. The largest (black) took longer to grow than the smallest (blue). This is Fig. S2c from supplementary online material for J. Kirkby et al., Nature, 476, 429-433, © Nature 2011

Long-anticipated results of the CLOUD experiment at CERN in Geneva appear in tomorrow’s issue of the journal Nature (25 August). The Director General of CERN stirred controversy last month, by saying that the CLOUD team’s report should be politically correct about climate change (see my 17 July post below). The implication was that they should on no account endorse the Danish heresy – Henrik Svensmark’s hypothesis that most of the global warming of the 20th Century can be explained by the reduction in cosmic rays due to livelier solar activity, resulting in less low cloud cover and warmer surface temperatures.

Willy-nilly the results speak for themselves, and it’s no wonder the Director General was fretful.

Jasper Kirkby

Jasper Kirkby of CERN and his 62 co-authors, from 17 institutes in Europe and the USA, announce big effects of pions from an accelerator, which simulate the cosmic rays and ionize the air in the experimental chamber. The pions strongly promote the formation of clusters of sulphuric acid and water molecules – aerosols of the kind that may grow into cloud condensation nuclei on which cloud droplets form. What’s more, there’s a very important clarification of the chemistry involved.

A breach of etiquette

My interest in CLOUD goes back nearly 14 years, to a lecture I gave at CERN about Svensmark’s discovery of the link between cosmic rays and cloudiness. It piqued Kirkby’s curiosity, and both Svensmark and I were among those who helped him to prepare his proposal for CLOUD.

By an unpleasant irony, the only Svensmark contribution acknowledged in the Nature report is the 1997 paper (Svensmark and Friis-Christensen) on which I based my CERN lecture. There’s no mention of the successful experiments in ion chemistry and molecular cluster formation by the Danish team in Copenhagen, Boulby and latterly in Aarhus where they beat CLOUD to the first results obtained using a particle beam (instead of gamma rays and natural cosmic rays) to ionize the air in the experimental chamber – see

What will historians of science make of this breach of scientific etiquette? That Kirkby was cross because Svensmark, losing patience with the long delay in getting approval and funding for CLOUD, took matters into his own hands? Or because Svensmark’s candour about cosmic rays casting doubt on catastrophic man-made global warming frightened the national funding agencies? Or was Kirkby simply doing his best (despite the results) to obey his Director General by slighting all things Danish?

Personal rivalries aside, the important question is what the new CLOUD paper means for the Svensmark hypothesis. Pick your way through the cautious prose and you’ll find this:

Ion-induced nucleation [cosmic ray action] will manifest itself as a steady production of new particles [molecular clusters] that is difficult to isolate in atmospheric observations because of other sources of variability but is nevertheless taking place and could be quite large when averaged globally over the troposphere [the lower atmosphere].”

It’s so transparently favourable to what the Danes have said all along that I’m surprised the warmists’ house magazine Nature is able to publish it, even omitting the telltale graph shown at the start of this post. Added to the already favourable Danish experimental findings, the more detailed CERN result is excellent. Thanks a million, Jasper.

Enlightening chemistry

And in friendlier times we’d be sharing champagne for a fine discovery with CLOUD, that traces of ammonia can increase the production of the sulphuric clusters a thousandfold. It’s highlighted in the report’s title: “Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation” and it was made possible by the more elaborate chemical analysis in the big-team set-up in Geneva. In essence, the ammonia helps to stabilize the molecular clusters.

Although not saying it openly, the CLOUD team implies a put-down for the Danes with this result, repeatedly declaring that without ammonia there’d be little cluster production at low altitudes. But although the Aarhus experimenters did indeed assume the simpler reaction (H2SO4 + H2O), differing results in successive experimental runs made them suspect that varying amounts of trace impurities were present in the air cylinders used to fill their chamber. Now it looks as if a key impurity may have been ammonia. But some members of the CLOUD consortium also favoured (H2SO4 + H2O) and early runs in Geneva used no intentional ammonia. So they’ve little reason to scoff.

In any case, whether the basic chemistry is (H2SO4 + H2O) or (H2SO4 + H2O + NH3) is an academic rather than a practical point. There are always traces of ammonia in the real air, and according to the CLOUD report you need only one molecule in 30 billion. If that helps to oil Svensmark’s climatic motor, it’s good to know, but it calls for no apologies and alters the climatic implications not a jot.

The experiment's logo. The acronym “Cosmics Leaving Outdoor Droplets” always implied strong interest in Svensmark's hypothesis. And the roles of the Galaxy and the Sun are acknowledged.

Technically, CLOUD is a welcome advance on the Danish experiments. Not only is the chemistry wider ranging but molecular clusters as small as 1.7 nanometres in diameter are detectable, compared with 4 nm in Denmark. And the set-up enables the scientists to study the ion chemistry at lower temperatures, corresponding to increasing altitudes in the atmosphere. Cluster production soars as the temperature goes down, until “almost every negative ion gives rise to a new particle” [i.e. molecular cluster]. The lowest temperature reported in the paper is -25 oC. That corresponds to an altitude of 6000 metres, so unless you wish to visualize a rain of cloud-seeding aerosols from on high, it’s not very relevant to Svensmark’s interest in the lowest 3000 metres.

How the warmists built their dam

Shifting from my insider’s perspective on the CLOUD experiment, to see it on the broader canvas of the politicized climate science of the early 21st Century, the chief reaction becomes a weary sigh of relief. Although they never said so, the High Priests of the Inconvenient Truth – in such temples as NASA-GISS, Penn State and the University of East Anglia – always knew that Svensmark’s cosmic ray hypothesis was the principal threat to their sketchy and poorly modelled notions of self-amplifying action of greenhouse gases.

In telling how the obviously large influences of the Sun in previous centuries and millennia could be explained, and in applying the same mechanism to the 20th warming, Svensmark put the alarmist predictions at risk – and with them the billions of dollars flowing from anxious governments into the global warming enterprise.

For the dam that was meant to ward off a growing stream of discoveries coming from the spring in Copenhagen, the foundation was laid on the day after the Danes first announced the link between cosmic rays and clouds at a space conference in Birmingham, England, in 1996. “Scientifically extremely naïve and irresponsible,” Bert Bolin declared, as Chairman of the Intergovernmental Panel on Climate Change.

As several journalists misbehaved by reporting the story from Birmingham, the top priority was to tame the media. The first courses of masonry ensured that anything that Svensmark and his colleagues might say would be ignored or, failing that, be promptly rubbished by a warmist scientist. Posh papers like The Times of London and the New York Times, and posh TV channels like the BBC’s, readily fell into line. Enthusiastically warmist magazines like New Scientist and Scientific American needed no coaching.

Similarly the journals Nature and Science, which in my youth prided themselves on reports that challenged prevailing paradigms, gladly provided cement for higher masonry, to hold the wicked hypothesis in check at the scientific level. Starve Svensmark of funding. Reject his scientific papers but give free rein to anyone who criticizes him. Trivialize the findings in the Holy Writ of the Intergovernmental Panel on Climate Change. None of this is paranoia on my part, but a matter of close personal observation since 1996.

It’s the Sun, stupid!” The story isn’t really about a bunch of naughty Danish physicists. They are just spokesmen for the most luminous agent of climate change. As the Sun was what the warmists really wanted to tame with their dam, they couldn’t do it. And coming to the Danes’ aid, by briefly blasting away many cosmic rays with great puffs of gas, the Sun enabled the team to trace in detail the consequent reduction in cloud seeding and liquid water in clouds. See my post By the way, that research also disposes of a morsel of doubt in the new CLOUD paper, about whether the small specks made by cosmic rays really grow sufficiently to seed cloud droplets.

As knowledge accumulated behind their dam and threatened to overtop it, the warmists had one last course to lay. Paradoxically it was CLOUD. Long delays with this experiment to explore the microchemical mechanism of the Svensmark effect became the chief excuse for deferring any re-evaluation of the Sun’s role in climate change. When the microchemical mechanism was revealed prematurely by the SKY experiment in Copenhagen and published in 2006, the warmists said, “No particle accelerator? That won’t do! Wait for CLOUD.” When the experiment in Aarhus confirmed the mechanism using a particle accelerator they said, “Oh that’s just the Danes again! Wait for CLOUD.”

Well they’ve waited and their dam has failed them.

Hall of Shame

Retracing those 14 years, what if physics had functioned as it is supposed to do? What if CLOUD, quickly approved and funded, had verified the Svensmark effect with all the authority of CERN, in the early 2000s. What if the Intergovernmental Panel on Climate Change had done a responsible job, acknowledging the role of the Sun and curtailing the prophecies of catastrophic warming?

For a start there would have no surprise about the “travesty” that global warming has stopped since the mid-1990s, with the Sun becoming sulky. Vast sums might have been saved on misdirected research and technology, and on climate change fests and wheezes of every kind. The world’s poor and their fragile living environment could have had far more useful help than precautions against warming.

And there would have been less time for so many eminent folk from science, politics, industry, finance, the media and the arts to be taken in by man-made climate catastrophe. (In London, for example, from the Royal Society to the National Theatre.) Sadly for them, in the past ten years they’ve crowded with their warmist badges into a Hall of Shame, like bankers before the crash.


J. Kirkby et al., Nature, 476, 429-433, 2011. The authors list and abstract are available at


H. Svensmark & E. Friis-Christensen, E., J. Atmos. Sol. Terr. Phys., 59, 1225–1232, 1997

Relevant Danish experimental reports since 2006, not cited in the new CLOUD paper

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 SKY experiment in a basement in Copenhagen.

Martin Andreas Bødker Enghoff; Jens Olaf Pepke Pedersen; Torsten Bondo, Matthew S. Johnson, Sean Paling and Henrik Svensmark, ‘Evidence for the Role of Ions in Aerosol Nucleation’, Journal of Physical Chemistry A, Vol: 112, pp. 10305-10309, 2008. Experiment in the Boulby deep mine in England.

M.B. Enghoff, J. O. Pepke Pedersen, U. I. Uggerhøj, S. M. Paling, and H. Svensmark, “Aerosol nucleation induced by a high energy particle beam,” Geophysical Research Letters, 38, L09805, 2011. Experiment with an accelerator in Aarhus.

global warming want to bet


Climate Change: News and Comments

Global warming – want to bet?

From the sweepstake's website

The smart money is on global warming,” declared a tipster in the journal Nature, back in 2001. John Whitfield was commenting on a short article in Science about an annual sweepstake on the date and time of springtime melting of river ice at Nenana in central Alaska. As Nature in London and Science in Washington have been the Tweedledum and Tweedledee of climatic alarmism, the prediction was consistent with editorial beliefs.

The tripod on 27 April 2010. From Ice Clasic Website.

Nenana is about 60 km south-west of Fairbanks, Alaska’s biggest inland city, and the townsfolk manage the sweepstake in support of local charities. They call it the Nenana Ice Classic, and this year’s betting closed on 5 April 2010. Every March, they embed a tripod in the ice covering the Tanana River. When the ice melts in late April or early May, the tripod moves, tripping a wire that stops a clock. Public concern about the size of the jackpot ($279,000 in 2010) ensures consistency and supervision worthy of the most meticulous scientific fieldwork.

Supposing you followed Nature’s advice in 2001, and bet on an ever-earlier melt date, would that have helped you to win the sweepstake?

If you knew that El Niño warmings and volcanic coolings influence the Alaskan river ice, you might have prudently started from the ten-year average from 1992 to 2001. Correcting for leap years, the average melting date was May 1. In the subsequent nine years, 2002-2010, the Nenana clock stopped as shown here, with leap years starred. Five times the melt was earlier than in 1992-2001, but three times it was later. The average melting date remained stubbornly at May 1. Nature proclaimed in 2001 that “an Alaskan sweepstake has become a record of global warming.” Now the Nenana ice joins the growing number of indications that global warming has at least paused, since the mid-1990s.

Engineers who were building a bridge over the river at Nenana started the sweepstake in 1917, and an unbroken sequence of records exists. Regarding the event as a proxy for springtime temperatures in central Alaska, I here plot the data with early melts high and late melts low.

The black line is a mathematical curve fitted to the data (5th order polynomial). It has no special statistical warranty but it gives a fair impression of ever-changing trends in the Alaskan climate. Only from 1975 to 1995 was a trend towards earlier ice melts fully consistent with the theory of man-made global warming. By contrast, most of the ups and downs match nicely with long-term decreases or increases in cosmic rays reaching the Earth, as the Sun’s magnetic activity varied. The dip since 2000 coincides with increasing cosmic radiation during a time of weakened solar activity.

Should you have therefore bet on the Nenana ice breakup being later in 2010? Not necessarily, because the smart money is on El Niño. The earliest melts in the Nenana record were on April 20 1940 (April 21 if not a leap year) and on April 20 1998. Both followed strong El Niño warmings in the eastern Pacific. So anyone aware of the major El Niño in progress in recent months might well have wagered on an April melt. In any case, you have to predict the time of day of the breakup – by hour and minutes – which leaves the most thoughtful analyst with little advantage over the general public in Alaska, who may just guess.

Simpler and surer bets about the climate take a long time. Ten years ago, mirth and outrage followed my suggestion on German television that global warming had stopped. That led to a written wager with the TV producer.

My expectation was a little premature and in 2006, because the satellite data did not go my way, I handed over the € 500. Much more important than that was my growing confidence that I had not misled the German TV viewers about global warming having stopped. Henrik Svensmark and Eigil Friis-Christensen in Copenhagen confirmed it in 2007, using tropospheric and oceanic temperature data. Others did so with officially publicized surface temperatures, so that by 2009 Kevin Trenberth, a prominent global warmer at the US National Center for Atmospheric Research, was admitting in a leaked “Climategate” e-mail that “we can’t account for the lack of warming at the moment and it is a travesty that we can’t”.

Do we see just a hesitation in global warming, or the start of a prolonged cooling? In the second edition of The Chilling Stars (2008), Svensmark and I said “enjoy the global warming while it lasts”, and Svensmark repeated the remark in a Danish newspaper in 2009. Words, you might say, come cheap, but two Russian physicists have serous money riding on an expected decline in temperatures.

Vladimir Bashkirtsev and Galina Mashnich at the Institute of Solar-Terrestrial Physics in Irkutsk published in 2003 a paper entitled “Will we face global warming in the nearest future?” They answered the question with a determined “No”. To account for what they called “the cooling that has already started” Bashkirtsev and Mashnich traced the clear link between sunspot counts and temperatures, in Irkutsk and globally, over the period 1882-2000, and they went on to endorse a prediction that sunspot cycles would weaken over the coming decades.

In 2005, the Russian pair agreed to a $10,000 bet about it with James Annan, a British pro-warming climate modeller working in Yokohama. As reported by Jim Giles in Nature, Mashnich and Bashkirtsev said that the average global surface temperature in 2012-17 would be lower than in 1998-2003, using data from the US National Climatic Data Center. Solar activity certainly seems to have declined in the Russians’ favour. But like the gamblers themselves, onlookers must now wait until 2018 to know the outcome. A merit of the Nenana Ice Classic is that it demands only a few weeks’ patience from the punters .


J. Whitfield, “Warm favourite”, Nature News, published online, 26 October 2001 doi:10.1038/news011101-2

R. Sagarin & F. Micheli, “Climate Change in Nontraditional Data Sets”, Science, Vol. 294, p. 811 2001

Nenana Ice Classic

Nenana melt records are available from the University of Colorado at

H. Svensmark and E. Friis-Christensen, ‘Reply to Lockwood and Fröhlich – The Persistent Role of the Sun in Climate Forcing’, Danish National Space Center Scientific Report, 3/2007

K. Trenberth, “Re: BBC U-turn on climate”, email to Michael Mann et al. 12 Oct 2009

J. Giles, “Climate sceptics place bets on world cooling down”, Nature, Vol. 436, p. 897, 2005

V.S. Bashkirtsev & G.P. Mashnich, G.P., “Will we face global warming in the nearest future?” Geomagnetism and Aeronomy, Vol. 43, pp. 124-127.2003.

About The Manic Sun


Explaining where this book about the solar influence and the cosmic ray connection fits into the climate change story

About The Manic Sun: Weather Theories Confounded

Here, in plain language, is the story of the battle between the solar theory and the greenhouse theory.” So read part of the blurb for my book The Manic Sun, published by Pilkington Press in 1997. It continued: “Knud Lassen, Eigil Friis-Christensen and Henrik Svensmark, alone in Copenhagen, took on a global regiment of supercomputer operators. After years of disparagement the Danes have, for the time being, won the fight.”

“The solar-terrestrial Vikings” Friis-Christensen, Svensmark & Lassen. Photo: Kirsten Fich Pedersen for The Manic Sun

My first contact with Friis-Christensen had been five years earlier while working on a TV script about the Sun for the European Space Agency. Together with Lassen, Friis-Christensen had published in Science in 1991 a report that linked the changing temperature of the Northern Hemisphere to the length of the sunspot cycles – shorter cycles meaning warmer weather. It was powerful evidence for a solar influence on the climate but the puzzle remained, how did the Sun do it?

In 1996, in Denmark on completely different business, I telephoned Friis-Christensen to see how he was getting on with his climate story. There was someone he’d like me to meet, he said. This was Svensmark, who next day divulged to me, in confidence, the link between cosmic rays and cloud cover. As soon as I was back in England I contacted Alec Jolly for the Pilkington Press and the commissioning, writing and publication of The Manic Sun went very rapidly, though not so fast as to break any secret.

In the years that followed, thoughts about updating The Manic Sun kept nagging, but by 2006 the Svensmark hypothesis had progressed so much that that only a new book would do. Icon Press took it on and the outcome was The Chilling Stars jointly authored by Svensmark and me.

A questioner once asked me after a lecture if I’d change much in The Manic Sun, I said No, nothing. It remains a good record of thought processes in the 1990s, including my rather naïve optimism about the speed of impact of Svensmark’s discovery. But I did admit that maybe the title was wrong. While two manic phases of solar magnetic behaviour explained most of the global warming of the 20th Century, by time the book came out global warming was coming to an end, because the Sun had gone into a depressive mood. But that was with hindsight, and in any case The Lazy Sun might win no prizes as a title.

Comment on The Manic Sun

While the `greenhouse theory’ is more strongly supported by science, the rival solar theory has many statistics in its favour. … Its subtitle is “Weather Theories Confounded”, and indeed a good deal of the book is devoted to arguing against the theories of greenhouse gases and global warming. But it is what Calder sees as the political manipulation of scientists that provokes his strongest reactions. William Hartston The Independent

You can buy The Manic Sun at:



In Danish Den Maniske Sol:

In Dutch De Grillige Zon:

In German Die Launische Sonne:



The Svensmark hypothesis

Sequence of discoveries

The connection between cosmic rays and the cloud cover observed by satellites was announced at a space science meeting in 1996 and published in the following year (Henrik Svensmark & Eigil Friis-Christensen 1997). The report’s title called the discovery the “missing link” because it solved a big puzzle for climate researchers, as to how the Sun could exert an impact on climate that empirically exceeded by a wide margin the effect of variations in solar brightness measured by satellites. Read the rest of this entry »