Circles from ash
How about the following theory about the “fairy circles” in Namibia (3 April, p 12)? In the past, land may have been cleared of unwanted trees, shrubs or weeds to turn the land into more friendly pastures or for the planting of crops. The removed vegetation was then stacked in heaps, left to dry and ultimately set on fire. Noxious substances captured in the plants, with or without the influence of the heat created by the fire, concentrated in the ash and poisoned the earth below. On the periphery, ash from lighter vegetation such as grass and shrubs acted as a fertiliser causing more luscious growth.
I would suspect that the noxious plant could have been a substantial tree which was chopped and burnt where it fell. Lighter vegetation would then be carried to the site of the fire and added to the periphery. I have noticed similar “fairy circles” in the vicinity of Darling, about 100 kilometres north of Cape Town.
It has to be nuclear
You ask whether we wouldn’t do better to stop the problem of global warming by what you call the “prosaic methods” of improving energy efficiency and boosting renewable energy sources (27 March, p 3).
Prosaic or not, these methods are not effective. Increased efficiency usually increases demand, because it makes fuel less costly. Despite efficiency measures introduced in the UK after the 1970s oil crisis, energy demand has risen steadily, in line with GDP.
Renewable methods of generating electricity have similar unintended consequences; they make conventional methods less efficient as these have to stand by as back-up, and they require a huge investment in infrastructure such as new power lines. Both factors increase the cost of electricity.
Nor will renewable methods have much effect on CO2 emissions. They are medieval meddling when high-tech solutions like nuclear power are required. So the answer to your question is no. If we can’t reduce CO2 output by switching to nuclear power, we will need some extraterrestrial solution.
Bird flu factories
So bird flu is a “ticking time bomb” (27 March, p 6). Why are we surprised that we are increasingly reaping the rewards of decades of factory farming? Packing thousands of the same species, deliberately bred to be genetically almost identical, into ever decreasing spaces is the ideal lab for pathogen evolution.
Add to that the stress of such cramped and unnatural conditions, with its known immunosuppressant effect, and bird/swine flu/fever pandemics are not just likely, they are inevitable. Some might say it’s no more than we deserve.
Running a temperature
Apart from scientific and technical arguments over how to manipulate the climate and its possible, unforeseen, consequences, what about the politics (27 March, p 26)?
Any attempts at climatic manipulation are likely to be expensive. This means rich countries will be in charge and the main player will almost certainly be the US 鈥� which will want the climate manipulated in the interests of US farmers. And if this leads to droughts and famines in other parts of the world, US agribusiness will have food to sell.
For the record
鈥� We gave an incorrect reference for the meta-analysis by Alec Buchanan and Morven Leese discussed in the feature “Bad or mad?” (20 March, p 38). This should have been “Detention of people with dangerous severe personality disorders: A systematic review”, The Lancet, vol 358, p 1955.
Letter
Dickson has obtained the chemical energy in a pint of beer, but surely what we really need is the physical energy 鈥� from good old E = mc2. This works out at 5.1 脳 1016 joules. That’s enough energy to put 272,000 African elephants into low Earth orbit.
Elephants and beer
I have to take issue with Ian Dickson’s answer to Feedback’s question “how many joules does your beer mug hold?” (27 March).
If we take a pint (0.568 litres) of pale ale (typical density 1.043 kilograms per litre), and remember that the speed of light in a vacuum is 2.998 脳 108 metres per second, Einstein tells us that the energy content of a pint is equal to 1.043 脳 0.568 脳 (2.998 脳 108)2 = 5.3 脳 1016 joules. If my arithmetic is correct, this is equivalent to the energy required to lift 100 million African elephants from sea level to the top of Everest.
Fateful butterfly
You talk of the possibility of butterflies fluttering around the heads of dinosaurs 65 million years ago (27 March, p 17). This was presaged in Ray Bradbury’s brilliant story The Sound of Thunder, published in 1952.
The story was set in 2055 and the US had just elected a new president, a wise and principled man. A group of rich hunters join a time-machine safari that returns to 65 million ago. They are permitted to shoot a Tyrannosaurus rex that is about to die anyway. Unfortunately things go awry and a butterfly is killed as well. When they return to 2055 they find that the future has subtly changed and that the other presidential candidate, a loathsome man, has been elected instead. And all this because of the death of a butterfly.
It may be that this story contains the first published hint of what became chaos theory.
Experimenter effect
Brian Clegg asks if the vaunted “experimenter effect” of parapsychology might occur in other fields (27 March, p 30).
In Surely You’re Joking, Mr Feynman! Richard Feynman relates the history of attempts to accurately measure the charge of an electron that demonstrate precisely that effect. He goes on to mention methods critical to the scientific process which help to combat this tendency to find what one is looking for.
It is well known in all branches of engineering that the only way to test properly a new design, software module and so on, is to get a third party to do the work. Designers are known to subconsciously “protect” the fruits of their imagination and labour, whereas someone with less emotional investment can be more objective, and find problems that would otherwise not be considered.
Danger of eating
With regard to your review of Beyond Coincidence (20 March, p 54): out of 10 million people 1 will die in a plane crash and 40 will die from choking. But all of these 10 million people are eating several times a day, every day of their lives, whereas the number of plane trips will be vastly fewer.
You are far more likely to die on one particular plane trip 鈥� if you take a plane trip 鈥� than on one particular mouthful of food, so no wonder we are more worried about the planes.
Letter
You ask the question: “Whose hand would be on the global thermostat?” Does it matter? As long as the US (largest emitter of CO2), Australia (largest per capita emitter) and China (fastest growing economy) arrogantly refuse to curb their emissions, we can easily answer the converse question: Whose hand is on the global thermostat now?
Letter
Am I missing something here? Why has it taken scientists so long to “believe that entanglement between particles exists everywhere, all the time”? Surely, if entanglement is true and the big bang is true, there is no surprise to be had. If at some time everything was on top of everything else, wouldn’t that do it?
Entangled web
Michael Brooks’s suggestion that physicists now believe entanglement between particles exists everywhere, all the time, as exemplified by light photons travelling from a star, brings wry smiles to we wave physicists (27 March, p 32).
We are quite at home with light waves interacting with the atoms of the star, and bringing us evidence of those atoms. But entanglement physicists believe observation of that light affects all those atoms instantaneously. They are clearly in a tangle.
Letter
Your contributor states: “Biofuels like soya oil鈥re ‘carbon neutral’ because the carbon they release came from the atmosphere only recently.”
This is incorrect. Carbon-neutral fuels are those in which the CO2 “embodied” in their production is equivalent to that given out when they burn. Soya oil requires 3 to 4 times as much energy to produce as is contained in the usable fuel product. That energy comes from fossil fuels powering tractors, producing agrochemicals, transporting and processing the oil, and so on. So it is definitely not carbon neutral, it is heavily carbon emitting.
Flying on soya
It might make airlines think they are being “green”, but running planes on soya oil is hardly likely to slow climate change (27 March, p 22). Soya agribusiness is one of the most ferocious contributors to deforestation in South America, with vast swathes of the Chaco, the Brazilian cerrado, and the Amazon rainforests being cleared to feed the world’s already voracious appetite for soya.
A first step to curbing airplane emissions would be to throw out the 1948 international treaty that exempts aviation fuel from taxation. The world’s mad love affair with cheap air travel could be doused if only the fuel were taxed properly. Technical fixes will only delay the moment we decide to get serious about climate change and over-consumption.
Western conscripts
Your item on Saddam’s human rights abuses lists mutilation, murder, torture, kidnapping and forced military service (27 March, p 4). Large numbers of men in western democracies have suffered this last form of abuse. Should they be eligible for monetary compensation?
Nanniebots in doubt
After seeing your piece on “nanniebots” trapping chatroom paedophiles, I get the feeling I have read an unprocessed press release (20 March, p 23).
Given the quality of the chatterbots we see entering the Loebner prize each year, these are extraordinary claims, and need just a wee bit of confirmation.
The editor replies:
鈥� If nanniebots can lead to investigations of paedophiles, as claimed by their inventor Jim Wightman, this is pretty persuasive evidence that they work. We have now learned from the UK’s National Hi-Tech Crime Unit, London’s Metropolitan Police and the FBI that they are unable to confirm that this has happened. Both UK agencies deny any active involvement with Wightman’s programs. If new evidence emerges, we will keep readers up to date.
Letter
Why stop at tiny, shiny balloons or a giant parasol to protect us from global warming? Surely George W. can be persuaded to build a giant rocket to accelerate the Earth into an orbit that is farther away from the sun?
Letter
I was taken aback by the Klaus Lackner plan to strip CO2 from the atmosphere by wafting air across CO2-absorbing chemicals such as calcium hydroxide. As the only viable method of making calcium hydroxide is by heating calcium carbonate 鈥� usually by burning fossil fuels 鈥� and driving off the CO2 into the atmosphere, the scheme is apparently a multibillion-dollar method of increasing the level of CO2 in the atmosphere.