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

What Language on Mars? (2)


Predictions Revisited

The Chinese space programme

Still catching up after Christmas, I’ve been reading an official report from China issued on 29 December, about their plans for space activities in the next five years. In a post in August 2010 called “What language will they speak on Mars?” the answer was “Chinese, on present showing”.

It harked back to a prediction by Wernher von Braun made in 1964.

Man may have landed on the surface of Mars by 1984. If not, he will surely have made a close approach for personal observation of the red planet. Likewise, manned ‘fly-bys’ to Venus will have been made.

Lunar landings will have long since passed from the fantastic achievement to routine occurrence. Astronauts will be shuttling back and forth on regular schedules from the earth to a small permanent base of operations on the moon.

Although unstated, von Braun’s reliance for the Mars flight was on a nuclear rocket called Orion, which was cancelled soon after he wrote his article. Since then the US space programme has faltered or veered about under a succession of Presidents with different priorities. The present lack of American transport to take people to the International Space Station ranks with the British navy’s current construction of aircraft carriers for which there’ll be no suitable aircraft.

By contrast the Chinese space engineers, although starting about half a century behind the USA and Russia and still only moderately funded, are now moving steadily ahead with a programme that has clear and mutually compatible objectives. The new plan includes developing a space laboratory and collecting samples from the Moon by 2016, and building a more powerful manned spaceship. No date is given for a manned landing on the Moon, but that is under study.

A module for a Chinese space laboratory, the eight-ton Tiangong-1 (“Heavenly Palace-1”), lifted off from the Jiuquan launch site near the Gobi Desert on a Long March 2FT1 rocket on 22 September 2011. Image: Caters News Agency.

The Army coordinates the space programe. Although the report is careful to say, China always adheres to the use of outer space for peaceful purposes, and opposes weaponization or any arms race in outer space, there’s military significance in the BeiDou (“Compass”) navigation satellites. Western and Russian systems are downgraded to stop them guiding hostile missiles too precisely. But with ten BeiDou satellites already launched and focused on East Asia, the Chinese intend to have a 35-satellite global navigation system by 2020.

As for their first shot at Mars, the Chinese have been thwarted by the hoodoo on Russian missions to the Red Planet. Yinghuo-1 (“Shining Planet”) rode piggyback on the Russian Phobos-Grunt spacecraft launched from Baikonur on 8 November last. The pair failed to escape from Earth orbit and disintegrated into the Pacific Ocean on 15 January. There’s been word that the Russians would like to blame a US radar for spoiling their mission, but that’s far-fetched. And the name Yinghuo-1 surely implies that the Chinese will try again.

The post “What language will they speak on Mars?” is here

You can read the full Chinese report in English here (clicking on the panels 1, 2, 3 etc at the bottom of each page)

The Royal Aeronautical Society will have a lecture at its London HQ about “China’s Expanding Space Programme,” next Thursday, 26 January, at 8 pm. Karl Bergquist of the European Space Agency, a Swede fluent in Mandarin. Summary, details and registration here

Dying comets probe the Sun


Updating Magic Universe

Debris traces the solar magnetic field

What started as a bonanza for comet spotters becomes a new tool for exploring levels in the Sun’s atmosphere that have been hard to see up to now. The SOHO spacecraft (Solar and Heliospheric Observatory) has identified more than 1400 small “sungrazing” comets that fly close to the Sun and evaporate. In July last year, the comet observers using SOHO’s Large Angle and Spectrometric Coronagraph (LASCO) team alerted colleagues operating the newer SDO (Solar Dynamics Observatory) to a larger-than-usual sungrazer heading for its doom.

As he reports in the current issue of Science magazine, Karel Schrijver from the Lockheed Martin Advanced Technology Center in California tracked Comet 2011 N3 SOHO by extreme ultraviolet light with his Atmospheric Imaging Assembly on SDO, which observes highly ionized atoms. What he learned about the comet and about the Sun I’ll tell below as a concise update for Magic Universe. Meanwhile the word is that SDO also observed Comet Lovejoy last month, when it survived a close encounter with the Sun, passing behind it and reappearing on the other side.

Here are a few relevant paragraphs from my story about Comets and Asteroids in Magic Universe.

The big comet count came from another instrument on SOHO, called LASCO, developed under US leadership. Masking the direct rays of the Sun, it kept a constant watch on a huge volume of space around it, looking out primarily for solar eruptions. But it also saw comets when they crossed the Earth-Sun line, or flew very close to the Sun.

A charming feature of the SOHO comet watch was that amateur astronomers all around the world could discover new comets, not by shivering all night in their gardens but by checking the latest images from LASCO. These were freely available on the Internet. And there were hundreds to be found, most of them small ‘sungrazing’ comets, all coming from the same direction. They perished in encounters with the solar atmosphere, but they were related to larger objects on similar orbits that did survive, including the Great September Comet (1882) and Comet Ikeya-Seki (1965).

SOHO is seeing fragments from the gradual break-up of a great comet, perhaps the one that the Greek astronomer Ephorus saw in 372 BC,’ explained Brian Marsden of the Center for Astrophysics in Cambridge, Massachusetts. ‘Ephorus reported that the comet split in two. This fits with my calculation that two comets on similar orbits revisited the Sun around AD 1100. They split again and again, producing the sungrazer family, all still coming from the same direction.’

The progenitor of the sungrazers must have been enormous, perhaps 100 kilometres in diameter or a thousand times more massive than Halley’s Comet. Not an object you’d want the Earth to tangle with. Yet its most numerous offspring, the SOHO-LASCO comets, are estimated to be typically only about 10 metres in diameter.

Update January 2012

In July 2011 a larger than usual sungrazer spotted by SOHO was tracked across the face of the Sun by a newer spacecraft, the Solar Dynamics Observatory, SDO. Named as Comet 2011 N3 SOHO, it evaporated to the point of invisibility after 20 minutes, but not before the event had transformed the game from comet-spotting fun to highly productive cometary and solar physics.

Led by Karel Schrijver from the Lockheed Martin Advanced Technology Center in California, the SDO team was able to gauge the size of the comet. Initially it was up to 50 metres wide. This opened the way to investigating the sungrazers in much more detail. It should become possible to learn more about the composition of these comets, according to how they boil and rupture in the intense heat.

As for solar physics, the miniature tail of the dying comet lit up magnetic field lines at altitudes high in the solar atmosphere that otherwise are almost impossible to detect. Seeing the lines traced by sungrazers at different heights above the Sun will make it possible to trace more accurately the links between the magnetism near the visible surface and the vast field that reaches out into space and influences the Earth.


Karel Schrijver et al., Science 20 January 2012, vol. 335, pp. 324-328 DOI: 10.1126/science.1211688

NB: Movies are available at

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:

Utopia beats Dystopia


Predictions Revisited

Let’s lay Malthus to Rest

After all that Halloween anguish about the global population reaching 7 billion, how refreshing to have an upbeat assessment of the world food situation! It comes from the retiring professor of sustainable development and food security at Wageningen University in the Netherlands. “Hindsights in Perspective” was the title of Rudy Rabbinge’s farewell address, and you can see a press release about it here

Two hundred years ago, Malthus predicted that the world would be unable to feed the growing population. The fact that he was manifestly wrong is illustrated by the current situation in which the population has increased seven-fold, but there is now more food per head available than in 1800.”

Other points from Prof. Rabbinge:


Rudy Rabbinge. Photo Wageningen U.

  • The notion of a present or future shortage is a misunderstanding – this is not the case anywhere in the world, except in China.
  • We do not need extra agricultural land in order to feed the world population in the coming decades.
  • The damage caused to the environment by farming has dropped considerably.
  • Ineffective policy, unequal distribution of production and poor food distribution still leads to a billion people going hungry — a disgrace that warrants a world-wide reaction.
  • Science gives cause for utopian thinking with good prospects rather than anti-utopian (dystopian) defeatism; whilst naive optimism is dangerous, unfounded pessimism is discouraging and frustrating,

Back in 1967, in The Environment Game (Secker & Warburg) I visualized an implosion of food production into small, intensive operations, such that most land could be restored to nature. This is a theme at Wageningen too:

Rabbinge refers to the energy-producing greenhouse (which could be operational in the coming years), energy-neutral buildings, and small-scale power generation by means of bio-solar cells. If agricultural production is concentrated at the well-endowed locations, geared up to high production, the world will be in a position both to sustain agro-biodiversity (the combination of natural disease control and biological control mechanisms in the fields) and to release areas of agricultural land for nature. This will require more energy per unit of area but less per unit of product.

Postscript: Prof. Rabbinge feels more affinity with the Malthus’s French contemporary, the mathematician and philosopher Condorcet, who believed in dramatic change thanks to man´s ingenuity. You can see the Marquis de Condorcet’s book on Progress (1795, trs into English 1796) here Before getting too zealously utopian, please remember that Condorcet was a prominent supporter of the French Revolution but then died as one of its many victims. Failures are due to politics, not science and technology.

For earlier posts about Malthusian errors see: and


Get every new post delivered to your Inbox.

Join 149 other followers