Professor Lord Martin Rees thinks that runaway anthropogenic global warming poses one of the greatest existential threats currently facing mankind – and he should know, given that he is a co-founder of The Centre for the Study of Existential Risk. Furthermore, as a former President of the Royal Society, his scientific credentials and professional integrity are surely beyond reproach. You will not find his name listed on the Pro-Truth Pledge website, simply because his stature places him well above the need for any virtue signalling. In the eyes of a doom-groomed public, his opinions carry a lot of weight. And guess what? He’s written a book.
Professor Rees’s book, On the Future: Prospects for Humanity, should be of interest to the readers of Climate Scepticism because his support for the CAGW hypothesis enjoys such a high profile. Accordingly, he gives the subject plenty of attention, particularly under the section heading, ‘Deep in the Anthropocene’.
Clearly, the bad news for the Anthropocene fans hasn’t reached Professor Rees yet, but that is not what I want to focus upon. Instead, I want to stay on the subject of personal credibility and how it matters when an individual holds forth on safety-critical issues. If someone like Professor Rees is worried, surely we should all be. And believe me, there is much in Professor Rees’s book to be worried about. For example, there is plenty of talk in his book of tipping points, together with alarming statements such as:
“The consensus of the IPCC experts was that business as usual, with a rising population and continuing dependence on fossil fuels, has a 5 percent chance of triggering more than six degrees warming in the next century.”
Despite my lack of training in climate science, I would venture to suggest that these are overstated risks. But Professor Lord Martin Rees, UK Astronomer Royal and former President of the Royal Society of London, says I’m ambitious; and Professor Rees is an honourable man.
Maybe so, but in a book in which he throws his scientific authority behind CAGW, we also find the following statement, commenting upon his level of confidence that particle accelerators such as the Large Hadron Collider (LHC) do not pose a threat to mankind:
“It is presumptuous to place confidence in any theories about what happens when atoms are smashed together with unprecedented energy. If a congressional committee asked: ‘Are you really claiming that there’s less than a one in a billion chance that you’re wrong?’, I’d feel uncomfortable in saying yes.”
Well, I find that very odd, because on CERN’s Media and Press Relations website, the same Professor Lord Martin Rees, commenting on the findings of CERN’s LHC Safety Assessment Group (LSAG) 2008 report, is quoted as saying:
“There is no risk [in LHC collisions, and] the LSAG report is excellent.“
To spell this out, he categorically dismisses the risk and then goes on to write a book that refuses to rule out the possibility that the LHC could destroy everything we know!
What are we to make of this? Is this the behaviour of an honourable man? If he is prepared to flatly contradict himself on matters of existential risk can we believe anything Professor Rees says about his views on CAGW? I suppose this all goes to show that there’s physics, and then there’s what physicists are prepared to say.
The kindest thing I can say regarding Professor Rees’s book and its claims for the existential risks associated with particle accelerators, is that he is playing upon lingering doubts. No matter how confidently one dismisses risks, the very fact that they were considered in the first place can leave one with an uneasy feeling. Furthermore, the LSAG report says there is no conceivable threat, but what it really means is that the conceived threats were all unrealistic. So, under the circumstances, it is tempting to be risk averse and say that if we only avoid the destruction of one universe, then the effort would probably still be worth it. Nevertheless, the LHC was switched on, it did its stuff, and the universe survived. And I suspect Professor Rees knows this.
Appendix: The science behind the supposedly existential risks of LHC operation1
Professor Rees’s book does not go into very much detail regarding the posited existential risks of particle accelerators, and it certainly fails to detail the scientific investigations that have already ruled them out. For those who are interested, this appendix provides such background. It has nothing to do with climate science, so feel free to ignore it if you wish.
In fact, the risks to which Professor Rees alludes had already been addressed long before the commissioning of the Large Hadron Collider. To be precise, the spectre of doom was first raised not for CERN’s LHC but for one of its predecessors – the Brookhaven Relativistic Heavy Ion Collider (RHIC) in the USA. As a consequence of these concerns, a safety committee was set up by Professor John Marburger, Director of Brookhaven National Laboratory, which reported in September 1999. When similar concerns were echoed for the LHC, a further investigation was instigated by CERN, which built upon the RHIC investigation. An initial report was published by CERN in 20032, and a follow-up, extended report appeared in 20083. The 2008 report was categorical in its findings:
“We conclude by reiterating the conclusion of the LHC Safety Group in 2003: there is no basis for any conceivable threat from the LHC. Indeed, theoretical and experimental developments since 2003 have reinforced this conclusion.”
In coming to this conclusion, the LHC Safety Assessment Group had considered the hypothetical creation of four objects, each of which could seriously ruin your day:
Microscopic Black Holes:
According to conventional general relativity theory, it is not possible to create a black hole as a result of a collision between two protons; the gravitational forces involved are just not great enough. It is only when one considers speculative gravitational theories based upon more than four space-time dimensions that such a possibility cannot be discounted. Even so, LSAG calculated that the energy generated by two protons colliding within the LHC is equivalent to two colliding mosquitoes, and so any black hole that might be created by the LHC would have to be much smaller than any known to astrophysics. Nevertheless, a black hole is a black hole and you wouldn’t want one in your back yard.
Thankfully, however, all black holes are destined eventually to evaporate to nothing as a result of Hawking radiation. The key point here is that the smaller the black hole, the faster the rate of decay, such that the type of black hole that might be produced by the LHC would lose mass faster than it could accrete it. As a result, the black hole would decay to nothing long before it had the opportunity to escape the walls of the collider. LSAG also backed up this theoretical argument by pointing out that ultra-high energy proton collisions are commonplace within the cosmos and so the LHC experiment has, in effect, already been conducted ten million, trillion, trillion times since the creation of the Universe.
The LHC research programme includes the collision of heavy ions, the purpose being to reproduce the plasma formed at the birth of the Universe. Most of the plasma’s material will be constructed from quarks that constitute ‘ordinary’ matter, i.e. from the up and down quarks. However, other more exotic quarks will also be produced, including the so-called strange quark. Nuclei that combine both up, down and strange quarks are known as lambda particles. Such particles have already been created experimentally (for example, by the RHIC) but have always proven to be unstable, decaying in about a nanosecond. The problem Martin Rees alludes to is this: What if stable strange matter (known as strangelets) could be produced? Such material might be more stable than the ordinary material with which it were to come into contact. A runaway conversion to strange matter could result, and the energy released during the conversion process would be enough to turn the Earth into a molten lump.
The technical argument offered in LSAG’s 2008 report is somewhat long and complicated, but it amounts to this: Firstly, no strangelets have ever been created in the laboratory, despite several years of RHIC operation. Secondly, even if stable strangelets were a possibility, a runaway conversion of surrounding matter would not be possible due to the thermodynamically determined upper limit for strangelet production – the strangelets would literally have a snowball’s chance in hell. Finally, a similar argument to that used for microscopic black holes is invoked: stable strange matter cannot be that easy to produce, otherwise we would surely see evidence for its existence in nature. For example, the Moon has existed for billions of years under the bombardment of high energy cosmic material, unprotected by a magnetosphere, and yet has remained resolutely non-strange!
Those of you who have a general interest in quantum mechanics will already be aware of the concept of the vacuum state. Put simply, a physicist does not consider empty space to be empty but permeated instead by fields, with virtual, field-mediating particles constantly flitting in and out of existence. The vacuum, therefore, has an energy state. The presupposition is that the vacuum energy that universally appertains is at a stable minimum since, if it weren’t, the state would have degenerated before now. But what if the vacuum energy is currently at a false minimum, i.e. the vacuum is in a meta-stable state? If this were the case, a high energy event in a particle accelerator could destabilise the existing vacuum to create a bubble of ‘true’ vacuum. The bubble would then expand at approaching the speed of light until it eventually engulfed the observable universe. The problem is that such a new order could not hope to support physics and chemistry as we know them, let alone biology. A more absolute catastrophe is impossible to conceive. Comforting, however, is the realisation that it hasn’t happened yet, despite 13 billion years of cosmic turmoil, so there is nothing to fear from the relatively puny efforts of the LHC.
Fears of magnetic monopoles were not raised in Professor Rees’s book, but I will deal with them anyway.
Of all the exotic objects posited by the LSAG study, magnetic monopoles are easily the weirdest. I do not have space to do them justice here but all you really need to know about them is that they exist only as a theoretical entity and, if they did exist in nature, they would be far too massive to be created in any existing particle accelerator, nor indeed any conceivable future accelerator. Furthermore, if they could be produced, their Earth-bound orgy of destruction would be short-lived since the energy generated by the destruction would propel the beastie out into space long before you could say “Oh dear, what can that matter be?”
 This article’s appendix largely comprises extracts from my previously published essay on the subject of particle accelerator safety, “Armageddon and Other Failure Modes”, the full version of which may be found in “25 at 25 – A selection of articles from twenty-five years of the SCSC Newsletter Safety Systems”, ISBN 9781540896483.
 Study of Potentially Dangerous Events During Heavy-Ion Collisions at the LHC: Report of the LHC Safety Study Group, Blaizot et al, CERN 2003-01.
 Review of the Safety of LHC Collisions, Ellis et al, CERN-PH-TH/2008-136.