Cool on potato
Ben Raskin of the Soil Association clearly exposes the problems of a failure to link agricultural production to the best nutritional outcomes (30 August, p 18). The S谩rpo potato cultivar that he lauds has been trialled by the UK Potato Council, but such blight-resistant varieties are not necessarily the potato of choice for processors or consumers. In other words, if you grow them, they may not be wanted.
In the UK we breed crop varieties for high outputs and customer requirements. There are also requirements for potato cultivars to be disease-resistant and suited to processing, preservation and consumption. Linking these processes together is critical to global food security, and current plant-breeding methods may require more precise biotechnological approaches to obtain a fit-for-purpose, nutritious cultivar. These pressures may realistically result in a genetically modified potato crop.
We must also ensure that poor biosecurity and phytosanitary practices do not continue to threaten global food security, particularly for seed crops. This will be achieved by evidence from field trials and official cultivar lists, not anecdotes or hearsay.
Myths and morality
Mary Midgley’s review of Gary Greenberg’s book The Noble Lie (13 September, p 46) addresses the important moral issue of the extent to which individuals are accountable for their actions, given that they may suffer from an addiction or mental illness, or environmental privations.
Members of my own family have suffered from such afflictions: experience suggests it is dangerous to be forced into making a simple choice between vice and disease. Alcoholism, for example, has aspects of both a disease and a vice. Effective treatment, as with many such afflictions, entails helping people get control over their lives.
Defining alcoholism as a disease is unhelpful because it implies that treatment is applied to a passive recipient. It steers us away from understanding alcoholism’s true nature and this must always be our aim, as scientists, therapists or sufferers.
Pain grief
Contrary to Rachel Nowak’s suggestion that in Australia “you can expect a reasonably comfortable end” (6 September, p 22), many cancer sufferers here spend months in agony when permitted maximum doses of palliative drugs become ineffective. In Australia, unlike the UK, such distress is exacerbated by a legal prohibition on the clinical use of heroin.
Apart from the misplaced fear of addiction that means even terminally ill patients may not get morphine in poor countries, there is the additional and also unjustified fear that a sufficient increase in dosage of a painkiller may hasten the end of a patient’s life. Only a religiously inspired sadist could raise such a fear, especially when a terminally ill patient is begging to die.
Beer goggles
You reported how individuals who have consumed alcohol find other people more attractive, and the author expressed surprise that this also applies to people of the same sex (16 August, p 12). It’s just proof of the adage: “What’s the difference between a straight man and a gay man? Four pints.”
Transplant offer
You may be interested in an additional way for the problem of the supply of organs for transplant (13 September, p 11) to be alleviated. I have tested my idea at 鈥� and been rewarded with the predictable responses that this is “unethical” and “ghoulish”, with the establishment donor organisations “we wouldn’t support such a scheme”.
Being an old bloke (67), I’m not expecting a rush of offers 鈥� but notwithstanding the obstacles to transplanting organs, whether they be donated or otherwise, such a market would create a larger pool of potentially available organs and that must be a step forward.
For the record
鈥� We said that a musical instrument called an epigonion was introduced to Greece in AD 180 (13 September, p 23) but the accompanying caption suggested the instrument was played in 440 BC. To clarify: AD 183 is the earliest documented date for the instrument’s existence; 440 BC is the date of the vase in the picture; and tradition has it that the epigonion was introduced to Greece by Epigonus, who lived around 600 BC.
鈥� Flu researcher Wendy Barclay recently left the University of Reading and is now (20 September, p 8).
Risk rank
Michael Bond’s chart of the risks from different transport types gives food for thought (30 August, p 34). The results are presented as deaths per billion passenger kilometres: this is most appropriate for comparing potential travel methods between fixed points. The apparent high risk of walking caught my attention. It raises questions about how this could be applied to other decisions, such as recreational use.
We may have a certain number of hours per week for relaxation and wish to decide whether to fly, drive, ride, pedal, sail or walk. For this purpose we can estimate the more appropriate figure of risk per hour by using an approximate average speed of travel for each category. The two-wheeled transports (of which I am extremely fond) now take the top of the podium and the car edges out walking. The aeroplane leaps to fifth place. Water transport still appears safer than my intuitive assessment.
Transport risk assessment literature discusses many complexities such as the risk of ground transport accident in airport commuting and the dependence of air travel risk on number of take-offs and landings.
Sporting risk and transport risk are not consistently comparable. Recreational aircraft figures are very different from commercial passenger aircraft. The deaths per billion anything in whitewater paddling and hang gliding could be shoehorned into this table and, I would suspect, displace the motorcycle from the number 1 spot.
Parachuting, scuba diving and base jumping would probably push the others to invisibility (even if we allow vertical metres to be included). The figures are not verified and the speeds are guesstimates, however the wide range of values in the derived data means that the chart will not change much if the input estimates change. The point is that the ratings can be altered dramatically by these two useful alternative units of risk.
My biased opinion is that walking is safer than driving anything, except on a motorway… or in Antarctica…
Electric caveats
You say a fuel consumption of 1.7 litres per 100 kilometres makes the ultimate “hypermiler” (20 September, p 26). My 200-watt e-bike achieves 0.5 litres per 100 km equivalent in traffic and has a 30-kilometre range using one low-toxicity lithium-ion phosphate battery. It cost less than 拢1000, provides low-impact, stress-and-diabetes-reducing exercise, and does not require motorways, multistorey car parks, refuelling stations, scarce metals, research resources, parking inspectors or squashed animals.
Yet I see no rush to change and China, the centre of mass electric bike use, is reportedly moving towards more cars.
The trouble with automobiles is that the issues are not only engines and efficiency. The transport industry and its infrastructure provide millions of jobs, and sustain (in Australia at least) a wider advanced manufacturing base. Cars also satisfy creature comforts 鈥� and of course fetish, as illustrated by the article’s illustrations.
Simply swapping electricity for petrol isn’t going to change these underlying drivers. As likely it will prolong demand for unsustainable resource use and degradation of the urban environment associated with our favourite form of transport.
From Brad Fregger
You got it right with your article on the advantages of the plug-in electric vehicle. It’s the best article I’ve ever seen on that technology. There’s no doubt in my mind that that’s the future. I celebrated by mowing my lawn with my battery-powered Neuton mower. It, too, has great advantages over the traditional gasoline-powered ones.
Austin, Texas
From Herman Nacinovich
I have made more than my fair share of bloopers in my time 鈥� but may I gently direct your attention to a tiny misprint: “regenerative breaking”? Or is it a reference to a design feature by the makers of Prius cars to facilitate disposal at the end of their design life?
Gulgong, New South Wales, Australia
Meat and methane
Bijal Trivedi’s article on the high carbon footprint of food (13 September, p 28) is a good illustration of the one of the problems caused by one particular farming system 鈥� modern intensive agriculture 鈥� but as her limited data from organic farming hints, to conclude that all farming systems have such high footprints would be a big mistake.
I did some rough calculations for my own smallholding in the south of England, run along traditional/organic lines. These indicate that our beef has much less than one-tenth, probably closer to one-fiftieth of the footprint of the intensively farmed North American steak mentioned in the article.
Meat production is a key part of most traditional/organic systems, in which grazing animals are a necessity in order to maintain fertility through crop rotation. Methane is also produced by micro-organisms in soil from plant decay; are not cows just replacing that process?
Electric caveats
Jim Giles correctly identified one of the major hurdles to electric cars coming of age as the need to bring down the cost of the lithium-ion battery (20 September, p 26). Another is the safety issue.
The cell membranes in lithium-ion batteries currently in production are combustible organic polymers. If the car is involved in an accident the stored energy released can ignite these and there is a risk of explosion.
The safety challenge is to produce cells that are immune to such catastrophic failure. Ceramic cell membranes are not combustible, but the technology does not yet exist to produce them affordably.
The article did include a side note about Sony having to recall a million lithium-ion laptop batteries because some had spontaneously caught fire, and referred to a solution being worked on at Stanford University involving cathodes made from silicon instead of carbon. However, I don’t believe that will solve the safety problem for cars, considering the stored energy they require.
From Andy Evan
I am curious. Jim Giles says lithium-ion batteries will take 5000 recharge cycles. Every laptop I have owned and used daily has a dead battery after a year 鈥� around 350 charges leave it lasting 10 minutes compared with the original 2 hours. Why?
Oxford, UK
From Owen Clarke
The Tesla car’s lithium-ion battery weighs 450 kilograms. Assuming it contains around 200 kg of lithium, building 5 million cars a year would require 1 million tonnes of lithium.
When will “peak lithium” occur? Knowing that would enable these cars to be judged in the context of a finite world.
Pontypool, Gwent, UK
From Adrian Gaylard
In stating that the Aptera “has a drag coefficient of just 0.15 鈥� making its drag roughly the same as that caused by a single large wing mirror”, Jim Giles is confusing the non-dimensional drag coefficient with the drag force. The size of the object must be accounted for to determine the force. If the Aptera has around 25 times the frontal area of a typical European mirror, the mirror would need to have a drag coefficient of 3.75 to generate the same drag force as an Aptera at the same speed. In practice, mirrors have drag coefficients much less than unity.
Bishop’s Itchington, Warwickshire, UK
From Brian Moss
You describe the Tesla Roadster’s top speed as 200 kilometres per hour, “electronically limited”. Now that all new vehicles have electronic management systems, it is surely time that all are limited to the legal speed limit. Much precious fuel would be saved, and accidents reduced.
Kingsbury, Warwickshire, UK
For the record
鈥� An editing error dropped a “not” from a letter by A Wills (online, 27 September). The American Dental Association that fluoridated water should not be used to make up babies’ bottle feeds.
Nonexistence theorem
James Humphreys queries (30 August, p 18) the distinction Lawrence Krauss draws between theism and atheism (2 August, p 52) when science makes suggestions about whether the universe has meaning.
Surely it is not possible to demonstrate the nonexistence in reality of an imaginary concept, although a conjurer might try. It is not, then, the responsibility of science to attempt the impossible.
It is incumbent on theists, on the other hand, who explicitly claim the existence of a deity, benevolent or otherwise, to demonstrate its reality.
In the absence of any such verifiable demonstration, science can only make impartial suggestions based on probability.
From Michael Whalley
James Humphreys has got hold of the wrong end of the stick. Science does not support atheism: it merely fails to support theism, leaving atheism as the default position by application of Occam’s razor. As several of your correspondents have pointed out, it is theism with its empirical claim (that there is a god) that is in need of evidence to back it up. Science does not provide any. Exactly the same reasoning applies to the belief in fairies. Scepticism does not require evidence; demolishing it does.
Howick, Quebec, Canada
Meat and methane
There is a real danger that trying to make sense of the complexity of calculating the greenhouse gas emissions associated with food (13 September, p 28) may lead to such unintended and environmentally damaging consequences as we have seen in the rush for biofuels reoccuring. For example, Bijal Trivedi says that the foods that produce most greenhouse gases are red meat and dairy products: but many of the statistics for beef production in particular are taken from very large-scale North American feedlots, where hundreds of thousands of animals are penned up and fed huge quantities of soya, maize and other grains to fatten them up as quickly as possible.
The environmental impact of sheep and cattle grazing grasslands is completely different. Their waste degrades naturally, and does not release methane as does that from industrially reared animals. Grazing animals are converting grass, which we cannot eat, into something we can.
Meat and dairy products from grass-fed animals contain more beneficial nutrients and contain healthier fat, and grazing animals help preserve some of the most beautiful and highly valued landscapes in the UK and the rest of Europe. Globally, grazing animals are a crucial source of food and income for some of the poorest people on the planet, living on marginal grazing lands that could never be cropped.
Grazing animals are protecting some of the most significant carbon stores on the planet: permanent grassland and other semi-natural and natural vegetation. If these grasslands were ploughed up, they would release huge quantities of carbon into the atmosphere.
From Charlotte Clarke
What are beleaguered hill farmers in Wales, the Lake District, the Yorkshire Dales and so on supposed to farm instead of livestock? Are we to condemn the populations of such areas to joblessness, while we feed on imported pulses which they cannot grow?
Harrogate, North Yorkshire, UK
Iced fuel
If the Boeing 777 was indeed brought down at Heathrow by ice in its fuel (13 September, p 23), it would not be the first. One night in 1948 or 1949 four Royal Navy Attacker FB2 aircraft “fell out of the sky” at Royal Naval Air Station Milltown in Aberdeenshire, UK. Each had almost total loss of power in its single Rolls-Royce Nene 102 engine. In the morning we could find nothing wrong, apart from water in their low-pressure fuel filters when they were drained 鈥� about the same amount in each. They all started without trouble and were ground-run successfully. We concluded that the filters had iced up to the extent that the fuel flow had been severely impeded, but that overnight the ice had melted and the problem vanished.
Careful investigation seemed to exonerate home base fuelling arrangements from being the source of the water, so we had to look elsewhere. Much of the fuel in the Attacker was carried in an exposed, virtually uninsulated, ventral tank. This would suffer severe cooling at altitude.
Aviation fuel at room temperature contains dissolved water. We thought this might have come out of solution and formed ice on the filters. From then on it was standard procedure to add a small amount of methanol as antifreeze when refuelling the ventral tank. As far as I know, there were no further problems of this kind.
Since no one was injured and no damage done the press evinced no interest. Possibly by now there are not a lot of us left who remember the incident, but Rolls-Royce may still have the details in their archives.