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.

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:

Target comet spotted


Updating Comets

Rosetta spies Comet Churyumov-Gerasimenko

The European Space Agency’s Rosetta spacecraft, launched in 2004, has just gone into hibernation until 2014, as it continues to cruise towards its far-flung rendezvous with a comet. Once there it will drop a lander on the nucleus and then accompany the comet as it orbits towards the Sun. Before Rosetta went to sleep, its camera OSIRIS was able to pick out its target, Comet Churyumov-Gerasimenko,160 million kilometres away among the background stars. This is the picture released today from the Max Planck Institute for Solar System Research (MPS).

Caption: Seen in the second enlargement from the crowded starfield of the Scorpius constellation, the comet became visible as a single point of light to the 10-cm OSIRIS telescope on Rosetta, thanks to exposures totalling 13 hours. Credits: ESA 2011 MPS for OSIRIS-Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA.

We had not expected to be able to create first images from so far away,” says the lead investigator for OSIRIS, Holger Sierks of MPS.

The press release from MPS is here

And from ESA here

By the way, next week (15 June) I’ll be taking part in an ESA TV programme about Rosetta and its predecessor Giotto, at ESOC, ESA’s mission control in Darmstadt.

Added 12 June: The event will start in the afternoon at 16:30 CEST. (15:30 BST) and will be webstreamed live at





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