Heating up
Gaia Vince suggests the use of land in the far north and south of the globe for food production, should farmland be lost through flooding or desertification (28 February, p 28).
The use of a Peters projection map rather than a Mercator map like that in the article would have shown that there is simply not enough land there. Of what there is, only a tiny proportion will have conditions suitable for successful farming. Also, the latitudes shown would have a much shorter growing season. The small pockets of fertile land in the far north and south are unlikely to be adequate compensation for the loss of existing farmland.
From Tracy Chandler
Relocating the majority of the world’s population, and producing technological solutions to climate change, as Vince suggests, will use up the last of our scant resources. Fuel, in particular, will be used in vast quantities. With 6 billion people to relocate, can we make enough vehicles that run on alternative energy to move them all?
Surely if population is the biggest problem this is what should be addressed. If there are fewer people, there will be fewer mouths to feed, fewer homes to build and fewer people using resources.
Though politics, poverty and religion can be barriers to the use of birth control, this remains the best way to reduce the suffering that climate change will bring with a growing population. How do you make sure your children don’t starve to death? Don’t have so many.
Petersfield, Hampshire, UK
From Guy Cox
The assumption that nuclear power will still be available by the end of this century flies in the face of even the most optimistic estimates of uranium reserves.
Vince’s article also predicts that we will have the technology to move billions of the world’s poorest people to northern Europe, yet lack the technology to capture and store water from a “shorter but fiercer Asian monsoon” to keep the tropics productive.
Sydney, Australia
Suicide psychology
I was astonished by Robert Pool’s account of Thomas Joiner’s theory that anorexics find suicide easy because they are used to pain (28 February, p 37). It’s actually much simpler than that. When I was anorexic, the constant mental agony was so intense that the only relief from it was physical pain. I was almost constantly suicidal.
The low recovery rates for anorexia are due to the way it is treated. Current hospitalisation treatments are based on a fundamental misunderstanding of the condition. Anorexia is nothing to do with not eating; it is about having self-esteem so low that you feel like you are taking up too much space in the world. What people with anorexia need is reassurance that their lives are worth living and to find other things that they are good at, apart from not eating.
From Phil Thompson
Suicide prevention research might also be served by turning the question “why do people kill themselves?” on its head: why don’t more people kill themselves?
Death is unavoidable, but to bring it about early is a nearly universal taboo. The need for a strong survival instinct is obvious, but what are the neurological mechanisms that actually enforce it? Do those mechanisms vary much from person to person? Is it that the survival instinct is fairly consistent, and the only significant difference in suicidal tendencies comes from what it takes to overcome it?
Understanding better how the survival instinct works when it does work properly might help in figuring out what’s happening when it doesn’t.
Los Altos, California, US
Natural mathematics
Martin Rees’s article on mathematics (14 February, p 36) prompts the question: why is mathematics so effective in explaining the physical world?
We observe that the natural world is not entirely random, and see lots of structure and organisation 鈥� patterns, in other words. We observe that snowflakes often have a hexagonal structure, and that in spring the sun rises a few minutes earlier each day. Mathematics can be considered as the study and classification of all possible logical structures and all possible patterns, including those we see in nature.
This helps to explain why nature is described by mathematics. It should of course be added that in mathematics there are many patterns, such as complex numbers and string theory, that are not apparent in nature. This might be because nature does not use them, or because we have not yet observed them.
Seeing numbers
In her article on dyscalculia, Laura Spinney ignores the differences in the way we process and organise auditory and visual information (24 January, p 40).
The auditory system organises sounds according to their relationship in time, which is one-dimensional. The visual system organises images according to their relationship in space, which is three-dimensional. Almost all subjects taught in schools are based on the sequential, one-directional languages of words and numbers. Learning difficulties, such as dyscalculia and dyslexia, are experienced by those who learn better using visual techniques.
We learn to count through spoken numbers. To the visual-spatial thinker, the main understanding of that number will come from what is seen. But there is nothing about the spatial proportion of the symbol “5” to suggest it indicates five of anything at all.
For both dyscalculics and dyslexics, the problem to be overcome is how to translate the audio-sequential information into appropriate 3D images.
Inventive phrasing
Michael Brooks reports the contentious claim by Alison Pease that “Mathematics is not a discovery. It is something we invent” (28 February, p 34).
Clearly, the rules of mathematics apply prior to their discovery; they would not if they were merely invented. The Pythagorean relationship was there at the beginning of the universe, for example. My students often ask who invented mathematics, as if it has no connection with reality and was simply created to make life difficult for them.
It is more appropriate to say that the techniques of mathematics are an invention, in the same way that English is an invention. The relationships have always been there and await further discovery through a variety of means, whether computer assisted or not.
Trip to Lagrange
In relation to Stuart Clark’s story on the Lagrangian points (21 February, p 30), the gravitational fields of the Earth and sun do not cancel each other at the Lagrange points. They add up to a net acceleration towards the sun that is of the same magnitude as that experienced by the Earth. This results in an orbital period exactly the same as the Earth’s, so an object at that point maintains its position in relation to the Earth-sun pair.
There is one point where the two gravitational fields truly cancel out, 260,000 kilometres from Earth in the direction of the sun 鈥� much closer than any of the five Lagrangian points. At this true cancellation point, the trajectory of any orbiting body would briefly become a straight line.
A Lagrangian or cancellation point does not necessarily trap anything that falls into it: the L1, L2, L3 Lagrangian points and the true cancellation point are not flat but saddle-shaped, so cannot trap material. The L4 and L5 regions are cup-shaped and so, as you point out, they can.
Importance of sex
Anil Ananthaswamy interviews the next head of ATLAS, and the first question is: “What are your thoughts on becoming the first woman to head a particle physics experiment at the LHC?” (28 February, p 26). For a moment there I thought you had morphed into a women’s magazine circa 1970. What on earth has her sex got to do with anything?
Going forward
In Julian Smith’s fascinating “Ted’s excellent adventure” (31 January, p 36), the diagram of Ted Ciamillo’s submarine shows the rear fin as rigidly attached to its propulsion rods. This can’t be how it works. Instead of constantly thrusting the water to the rear, half the time the attachment would propel the water forward, causing the submarine to remain stationary.
Surely there must be some kind of hinge linking the fin to the rods, so that it moves in a similar way to a dolphin’s tail or a human diver’s swim fins.
Chilly history
Stephanie Pain wonders why 1708-09 was the coldest winter in Europe during the past 500 years (7 February, p 46). The coldest years of the Little Ice Age, based on temperature records inferred from stalagmites in Spannagel cave in Austria, included 1695 and 1714-16.
The eruption of mount Fuji in Japan on 16 December 1707 contained unusually large amounts of basalt, causing larger amounts of sulphur dioxide than usual to be emitted. Sulphur dioxide forms an aerosol in the lower stratosphere that propagates around the world over several months, reflecting sunlight and causing a mean global cooling of about 0.5 掳C for up to three years. Local temperature effects may be much greater. Adding this cooling to the already low temperatures of the period could explain why 1708-09 was particularly cold.
For the record
鈥� The picture illustrating the Insider article on Scandinavia (UK edition, 14 March, p 50) was actually UNIS, The University Centre in Svalbard, Norway.
鈥� In “Surviving in a warmer world” (28 February, p 28) we said that you could use “solar energy to split water in fuel cells”. We meant to say “using solar energy to split water to provide hydrogen for fuel cells”.
鈥� Our image of edible seafood depicted squid, not jellyfish as the caption said (7 March, p 43).
鈥� Energy costing the Earth? We twice referred to terrawatts rather than terawatts (28 February, p 40 and 14 March, p 42).
鈥� Colossus was used to decrypt messages enciphered on the Lorenz teleprinter machine, not Morse code messages (14 March, p 48).
Heating up
Gaia Vince’s article on what we might expect to happen “geophysically” as well as socially in the coming decades was sobering but not completely disheartening (28 February, p 28). However, by provisioning for an anticipated population increase to 9 billion people within about 50 years we are ignoring a crucial fact: we don’t have enough resources for the current 6.75 billion people on the planet. Before climate change allows the cultivation of currently deep frozen soils, it would probably be more realistic to cater for a much reduced population of 1 billion, as postulated by James Lovelock. Whether the awful cull of humanity will be imposed by conflict or by “planetary cleansing” regulatory methods remains to be seen.
As well as lagging the loft and switching off the lights, we might be wise to put off having that next child. It could all turn out to be just an awful dream, but in the words of Basil Fawlty, who also oversaw a crazily dysfunctional organisation, “I think we’re stuck with it”.
From Doug Grigg
“Surviving in a warmer world” was a great article. However, I am surprised that a simple rationing system of carbon emissions at user level has not been suggested.
If the initial ration per head were to be the current average annual usage per head as detailed in “Why bother going green” (17 November 2007, p 34) then the higher users would be restricted. The ration unused by some could be sold to ease the burden on those who could afford to waste energy. Over the years the ration could be reduced steadily until a desired target was reached.
Surely this would be superior to market based systems which involve lots of discussion but little reduction.
Cannonvale, Queensland, Australia
Tim Jackson
The solutions put forward in Gaia Vince’s article are interesting, but omit consideration of timescale. To relocate 9 billion people within 50 years would require continuous global house-building exceeding that of post-war Britain. It seems unlikely that while doing this we could simultaneously produce continent-wide solar energy farms and totally redesign the world’s agriculture.
Interestingly, if the world’s population were to be crammed into the “green zone” of Gaia Vince’s map, the overall population density would be about the same as it presently is in the UK. There is no indication of a need for high-rise cities with complex infrastructure and transport networks. Vast numbers of people arriving in a newly habitable area of Siberian marshland, impoverished by the costs of travel and rehousing, would be likely to only have the resources for a peasant lifestyle.
Haslingden, Lancashire, UK