Further attempt to falsify the Svensmark hypothesis

05/10/2011

Climate Change – News and Comments

Falsification tests of climate hypotheses

The trouble with clouds

Against the Danish physicist’s claim that cosmic rays influence the Earth’s low cloud cover and thereby the climate, there’s one contention that keeps turning up like the proverbial bad penny. During recent years, so the story goes, the Sun has been weak, cosmic rays have been relatively intense, and yet the expected increase in low clouds has not occurred. On the contrary, we’re told, low cloud cover has remained relatively sparse. That’s according the International Satellite Cloud Climatology Project, ISCCP, which pools data from the satellites of several nations,

The contention is repeated in a forthcoming paper in Journal of Climate by Ernest M. Agee, Kandace Kiefer and Emily Cornett of Purdue University, entitled “Relationship of Lower Troposphere Cloud Cover and Cosmic Rays: An Updated Perspective.” An advanced version of the full text is available from: http://curryja.files.wordpress.com/2011/09/agee-cosmic-rays.pdf A favourable commentary appears on the Ars Technica website: http://arstechnica.com/science/news/2011/09/do-cosmic-rays-set-the-earths-thermostat.ars?utm_source=rss&utm_medium=rss&utm_campaign=rss

Agee et al.’skey exhibit is their Fig. 2:

Over the period 1984-2008, cosmic ray variations (solid line) from a neutron counter at Kiel, Germany, are compared with cloudiness in the lower troposphere reported by ISCCP (broken line). Note the mismatch 2005-08. Agee et al. 2011, © American Meteorological Society.

And their abstract reads: An updated assessment has been made of the proposed hypothesis that “galactic cosmic rays (GCRs) are positively correlated with lower troposphere global cloudiness.” A brief review of the many conflicting studies that attempt to prove or disprove this hypothesis is also presented. It has been determined in this assessment that the recent extended quiet period (QP) between solar cycles 23-24 has led to a record high level of GCRs, which in turn has been accompanied by a record low level of lower troposphere global cloudiness. This represents a possible observational disconnect, and the update presented here continues to support the need for further research on the GCR-Cloud hypothesis and its possible role in the science of climate change.

 There’s glory for you! – meaning a fine knock-down argument, as Humpty Dumpty said to Alice. To uninformed eyes (meaning, sadly, most climate scientists and commentators) the graph looks like a devastating falsification of the Svensmark hypothesis. Readers might even be surprised by the cautious language in the abstract, about a “possible observational disconnect”.

In fact the authors have every reason for caution. The conspicuous downward trend in the ISCCP cloud data is almost certainly unreal. An expert view is that it results from changes in the operational status of the satellites from which the data are pooled – see the references below to Campbell 2004, Campbell 2006 and Evan et al. 2007.

If a satellite views clouds from a slanting angle it sees more low clouds than when it’s looking straight down. Changes in the population and orbits of satellites contributing to ISCCP data have tended to narrow the viewing angle to nearer the vertical. That will have reduced the reported cloudiness even if, in the real world, the cloudiness were unchanging or even increasing. The effect is seen in these early maps from Campbell.

Upper map: the trend in cloudiness from July 1983 to September 2001 across a grid box with 280 km squares, from the official ISCCP data with the annual cycle removed. Lower map: adjustment for the changing viewing angles of the satellites greatly reduces the areas of supposed loss of clouds (in blue). Campbell 2004.

The harsh fact is that supposedly real observations of clouds over the decades are in a state almost as parlous as the IPCC’s contradictory computer models of climate. Here is a summary of observed monthly cloud “anomalies” (i.e. variations) in five different data sets, published by the American Meteorological Society (ref. Arndt et al. 2010, see below).

Black: ISCCP D2 Total cloud amounts from multiple satellites 1983-2008

Red: MISR Multi-angle Imaging Spectroradiometer on NASA’s Terra satellite 2000-2009

Blue: MODIS Moderate Resolution Imaging Spectroradiometer on NASA’s Terra and Aqua satellites 2000-2009

Brown: PATMOS-x Cloud data derived retrospectively from NOAA’s Advanced Very High Resolution Radiometer flown on a long succession of US spacecraft 1982-2009

Violet: SOBS Cloud amounts from surface weather observations 1971-1996.

In each case the solid lines are 12-month running means.

By cherry-picking favourable data (e.g. MISR and MODIS) I might try to claim that clouds have indeed increased with the high cosmic ray levels of the past decade. But judiciously one can only say that, as long as the data are so poor and contradictory, the jury must remain out, on what clouds have done and are doing. The last thing that Agee et al. or anyone should attempt with this shoddy stuff is to falsify the Svensmark hypothesis, for which plenty of other evidence exists. This includes variations in low clouds observed by satellites over days rather than decades, as in the Svensmark, Bondo and Svensmark 2009 paper summarized and referenced here https://calderup.wordpress.com/2010/05/03/do-clouds-disappear/ and in the recent Serbian paper that infers cloudiness from day-night temperature differences, as I reported here https://calderup.wordpress.com/2011/09/10/do-clouds-disappear-4/

 

The data on cloudiness over the longer term will be improvable by retrospective number-crunching, with PATMOS-x leading the way for total cloud. I’m very encouraged to see, in the last plot above, that PATMOS-x (brown) provides almost a mirror image of the ISCCP variations (black). But the low-level cloudiness may be more difficult to improve.

PS: For the philosophical importance of the falsifiability of hypotheses, according to Karl R. Popper, see https://calderup.wordpress.com/2010/05/01/falsification-intro/

 References

It’s perhaps needless to say that none of these is to be found in Agee et al.’s paper.

G.G. Campbell, “View angle dependence of cloudiness and the trend in ISCCP cloudiness,” 13th AMS Conference on Satellite Meteorology and Oceanography, 2004

G.Garrett Campbell, “Diurnal and angular variability of cloud detection: consistency between polar and geosynchronous ISCCP products”, 14th AMS Conference on Satellite Meteorology and Oceanography, 2006

Amato T. Evan, Andrew K. Heidinger, and Daniel J. Vimont “Arguments against a physical long-term trend in global ISCCP cloud amounts” Geophysical Research Letters, 34, l04701, 2007

D.S. Arndt, M. O. Baringer, and M. R. Johnson, eds.: “State of the Climate in 2009”, Bull. Amer. Meteor. Soc., 91 (7), S1-S224, 2010

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Accelerator results on cloud nucleation (2)

17/05/2011

Climate Change News and Comments

Did you get the message?

I’m not sure that the significance of my 15 May post, about the accelerator experiment in Aarhus, has been fully grasped. Following my 13 May post, the blogosphere seems to be still in a “waiting for CLOUD” mode. Yes, it will indeed be fascinating to see the first results from CERN’s CLOUD experiment in two or three months’ time, but meanwhile we have the results from Denmark. Perhaps I was negligent in not giving a little history.

The first laboratory test of the Svensmark hypothesis was the SKY experiment in Copenhagen, the outcome of which was published by the Royal Society of London in 2007. The positive results were of course politically incorrect, because Henrik Svensmark’s discovery of the effect of cosmic rays on clouds gave the Sun a much larger role in climate change than supporters of the man-made global warming hypothesis would like to admit.

The warmists were offered a delaying tactic by physicists who said, “Ah, but the SKY people used only natural cosmic rays and radioactive sources. Don’t believe them unless the CLOUD experiment in Geneva, simulating the cosmic rays with a fully controllable beam of accelerated particles, gets similar results.”

Conveniently for the warmists, CLOUD was very slow to get going. Meanwhile the Danes continued with their own experiments, including the one using an accelerator at Aarhus, as reported in Geophysical Research Letters a few days ago. The most important points are:

  • The effect of cosmic rays in helping to seed cloud formation is verified with a particle accelerator, just as critics of SKY were demanding four years ago.
  • A simple radioactive gamma-ray source gave just the same results in the Aarhus set-up so the earlier insistence, that only an accelerator experiment would do, was unwarranted.

Nevertheless, let’s say good luck to the CLOUD team. Their big chamber should be able to trace the growth of aerosol seeds much farther than in the small chamber used at Aarhus. And they have a large programme of future work, simulating atmospheric conditions at different altitudes.

See the Aarhus University press release that came out yesterday evening: http://science.au.dk/en/news-and-events/news-article/artikel/forskere-fra-au-og-dtu-viser-at-partikler-fra-rummet-skaber-skydaekke/

For references and other links, see my previous post: https://calderup.wordpress.com/2011/05/15/accelerator-results-on-cloud-nucleation/

For a video interview with Jasper Kirkby of CLOUD see: http://physicsworld.com/cws/article/multimedia/45950

Added 18 May: Ah, now the word is spreading. See

Anthony Watts: http://wattsupwiththat.com/2011/05/17/new-study-links-cosmic-rays-to-aerosolscloud-formation-via-solar-magnetic-activity-modulation/

David Whitehouse: http://thegwpf.org/the-observatory/3016-new-evidence-that-cosmic-rays-seed-clouds.html

The second item quotes me directly, and at the end of the second paragraph I should really have said ionizing “gamma rays” instead of “particles” — I amended it on this blog a few hours after posting it.

Added 20 May: Friendly words from The Scientific Alliance

http://us2.campaign-archive1.com/?u=f1e3eeb023e7d88eff0dda8a2&id=ed0b77bcc3&e=ac788faa66


Sun cools? How daft!

07/10/2010

Climate Change – News and Comments

An active Sun cools the world? How daft!

Valiant efforts of British physicists to deny that the Sun is important in climate change have always been good for a laugh. Names like Mike Lockwood and Arnold Wolfendale spring to mind. But with what she’s published in today’s Nature a professor at Imperial College London, Joanna Haigh, wins the my Gag of the Year prize.

The 200-year-old problem for solar-terrestrial physicists is to explain why the historical record shows strong and persistent links between solar activity and climate change over decades, centuries and millennia. Variations in visible light won’t do the job. The only mechanism powerful enough is Svensmark’s hypothesis about cosmic rays governing low cloud cover – see https://calderup.wordpress.com/category/3b-the-svensmark-hypothesis/ .

Haigh has never gone along with Svensmark, preferring instead to focus on ultraviolet light from the Sun, which does vary more than the visible light, and generally to minimize solar effects on climate. But in her new paper she offers to tear everything up and scatter it to the wind, because a satellite measured an increase in the intensity of visible light between 2004 and 2007, when solar activity was in decline. From the paper:

Daily measurements of the solar spectrum between 0.2 mm and 2.4 mm, made by the Spectral Irradiance Monitor (SIM) instrument on the Solar Radiation and Climate Experiment (SORCE) satellite3 since April 2004, have revealed that over this declining phase of the solar cycle there was a four to six times larger decline in ultraviolet than would have been predicted on the basis of our previous understanding. This reduction was partially compensated in the total solar output by an increase in radiation at visible wavelengths.

As summarized in an ICL press release:

The researchers used satellite data and computer modelling to analyse how the spectrum of radiation and the amount of energy from the Sun has been changing since 2004. Instruments on the SORCE satellite have been measuring the Sun’s energy output at many different wavelengths. The researchers fed the data from SORCE into an existing computer model of the Earth’s atmosphere and compared their results with the results obtained using earlier, less comprehensive, data on the solar spectrum.

Read the rest of this entry »


Do clouds disappear? 3

09/08/2010

Falsification tests of climate hypotheses

Cosmic rays and clouds at various latitudes

An exchange with Prof. Terry Sloan of Lancaster University

I’m promoting to the start of a new post a comment on an earlier post that came from Terry Sloan, together with my reply and his comment on my reply. I’ve included a graph that he sent in an e-mail because it wouldn’t upload into the Comments section.

After that, the discussion continues here with further remarks from me.

Sloan is one of the severest critics of the Svensmark hypothesis that cosmic rays influence the Earth’s low clouds. The earlier post, entitled “Do clouds disappear when cosmic rays get weaker?”, was concerned chiefly with whether or not sudden changes called Forbush decreases have observable effects on cloud cover. You can see that post in full here: https://calderup.wordpress.com/2010/05/03/do-clouds-disappear/

But the present interaction with Sloan mainly concerns a different question, about the influence of the Earth’s magnetic field. To help readers to get quickly up to speed, here’s the most relevant extract from my original post:

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Star positions matter

18/06/2010

Updating The Chilling Stars

Why star positions matter for climate physics

The Making of History’s Greatest Star Map is an excellent account of the European Space Agency’s Hipparcos mission by the project scientist, Michael Perryman. It brings back vivid recollections:

  • of dismay after the launch in 1989, when the satellite failed to go into the right orbit and frantic steps were needed to improvise a survivable orbit and re-configure the observing programme.
  • of satisfaction when operations continued despite unplanned exposure to the Earth’s radiation belts, as well as some nasty solar flares, until the radiation damage became fatal in 1993.
  • of the appetizer in 1994, when early results of the Hipparcos star mapping helped in accurate prediction of the impacts of the fragmented Comet Shoemaker-Levy 9 on the planet Jupiter.
  • of joy on Isola di San Giorgo, Venice, in 1997 when the Hipparcos science team announced their first large-scale results, after a huge computational effort.

Hipparcos in an ESA impression

Astrometry took that great leap forward 30 years after Pierre Lacroute of the Strasbourg Observatory first proposed a space mission to measure the positions of stars, 20 years after Erik Høg of the Copenhagen Observatory refined the concept, and 17 years after ESA earmarked it as something to do. Ground-based astrometry had stalled, because of imprecisions due the turbulence of the atmosphere, and its remaining aficionados had little lobbying power. As a result, Hipparcos remained a distinctly European space project – the first in which there was no competition with the US or Soviet space science programmes.

Applications of the Hipparcos Catalogue of 100,000 plus stars and the Tycho 2 Catalogue with 2.5 million stars (to a lesser but still unprecedented accuracy) have ranged from detecting a bend in the Milky Way Galaxy to checking Einstein’s theory of gravity, General Relativity. But wanting to pursue here the relevance of Hipparcos to climate physics, I’m pleased to see that Michael Perryman points the way.

Michael Perryman. Photo by Richard Perryman

In The Making of History’s Greatest Star Map, pp. 236-243, Perryman notes the role of Hipparcos in refining observations the wobbles of the Earth’s axis, which are involved in the pacing of ice ages (the Milankovitch theory). Then he points to the link between solar activity and climate change, as evidenced by the Little Ice Age, the Medieval Warm Period and other variations. As to the mechanism for the solar connection, Perryman singles out the suggestion that cosmic rays, modulated by solar activity, influence cloud cover.

He continues the story with the Sun’s journey through the Galaxy and the icy intervals on Earth that correspond to exposure to intense cosmic rays when passing through spiral arms. That’s a major topic in The Chilling Stars and, as Perryman says, the Hipparcos data have improved our knowledge of motions in the Galaxy.

It’s reassuring when a professor of astronomy with no scientific or political axe to grind gives serious attention to the cosmic-ray/climate link (the Svensmark hypothesis). Let me reciprocate by reviewing what’s said about the climate-related significance of Hipparcos and its successor Gaia in The Chilling Stars and see if it needs updating or extending.

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Do clouds disappear? 2

24/05/2010

Added 12 June 2010: There is now a thoughtful reply from Eimear Dunne.

Climate Change – News and Comments, and an echo of a Falsification Test

Wake up! Models don’t trump observations

The most important article since I launched this blog on 1 May may be Do clouds disappear when cosmic rays get weaker? — see here https://calderup.wordpress.com/2010/05/03/do-clouds-disappear/

It tells of unremitting attempts to falsify the Svensmark hypothesis by claiming that there’s no important effect on global cloud cover when eruptions from the Sun briefly cut the influx of cosmic rays, in “Forbush decreases”. The centrepiece is a summary of results published last year by Svensmark, Bondo and Svensmark. They show very plainly, in observations of the real world, that Forbush decreases have big impacts both on aerosols (chemical specks that grow into cloud condensation nuclei) and on low-level clouds.

That earlier post continues with the efforts in 2009-10 by Wolfendale and Arnold and their collaborators, who try to deny the Svensmark group’s result, by using relatively weak Forbush decreases. Svensmark can explain exactly how the impacts in those cases are masked by quasi-random meteorological noise, like tigers hidden in a jungle’s undergrowth.

Real-world results by Svensmark, Bondo & Svensmark (2009) for the remarkable loss of fine aerosols from the atmosphere (black curve) following five strong Forbush decreases in cosmic rays (red curve). Each aerosol datum point is the daily mean from about 40 AERONET stations world-wide, using stations with more than 20 measurements a day.

New nonsense comes in an abstract posted on the CERN website. It’s for a paper by researchers at Leeds, to be presented at a meeting about aerosols in Helsinki in three months’ time.

At issue are the Svensmark team’s results on aerosols (see right).  These show fine aerosols disappearing from the sky, because the shortage of cosmic rays lessens the chemical production of the  clusters of sulphuric acid and water molecules that seed the aerosols.

According to the people in Leeds, that can’t be right because they have a computer model that contradicts it.

The GLOMAP model was developed by Ken Carslaw, and the unlucky person named as lead author is a graduate student, Eimear Dunne.

An open letter to the lead author


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Do clouds disappear?

03/05/2010

Falsification tests of climate theories

Do clouds disappear when cosmic rays get weaker?

or “Don’t you worry, my dear, we’ve seen no tigers”

The Sun makes fantastic natural experiments” Henrik Svensmark says, “that allow us to test our ideas about its effects on the Earth’s climate.” Most dramatic are the events called Forbush decreases. Ejections of gas from the Sun, carrying magnetic fields, can suddenly cut the influx of cosmic rays coming to the Earth from exploded stars.

According to the Svensmark hypothesis, cosmic rays seed the formation of low clouds, so there should be a reduction in the Earth’s low cloud cover in the aftermath of a Forbush decrease. During the past few years there have been repeated attempts to declare the hypothesis falsified, when various teams failed to find the expected decrease in the low cloud cover.

One morning in April 2008, I woke up to find that since midnight the BBC had spread all around the world the news that British physicists had more or less destroyed the Svensmark hypothesis. Violating a basic principle of objective reporting, the broadcasts went out before Svensmark himself had a chance to comment.

By lunchtime he and I had done our best to limit the damage – and the deception of the public – in brief radio and TV interviews. A remark from Svensmark went belatedly onto the BBC website, that the critic it quoted had “simply failed to understand how cosmic rays work on clouds”.

Two years later, critics still don’t understand it. But they go on telling the tale that Forbush decreases have no important effect on clouds, and the media go on echoing them. When Svensmark and his colleagues published in August 2009 a report that showed very clear effects, and explained why others had failed to see them, the BBC and almost everyone else ignored it. But not the scientific critics, who returned to the fray in December 2009 and February 2010. Read the rest of this entry »