Editor's pick: Using biomass to make fuel is a criminal waste (1)
Michael Le Page’s article barely scratches the surface of the problems with biofuel policy (27 July, p 23). Solar energy conversion involving wheat is around 0.06 per cent efficient. That is 1/250th the efficiency of the solar cells that we now see covering agricultural land.
This idea takes no account of the energy cost of planting, cultivation, fertilisers, pest and disease control, harvesting, processing and distribution of biofuel. Cover roofs in solar cells and leave the good earth for food and nature reserves.
Editor's pick: Using biomass to make fuel is a criminal waste (2)
Having worked for many years in the biomass field, I was delighted to read Le Page’s article. Using biomass to produce power or fuel, when it has much more important uses, should be a crime.
Politicians seem to believe that because biomass is mostly green it fits into a green future. Of course, it is our only source of renewable carbon. But the waste from sugar, paper and wood processing is more than sufficient to supply carbon-based feedstock for the chemical and plastics industry as well as for some very special fuels.
Are 'septic foci' returning to haunt and hurt us?
Debora MacKenzie reports work suggesting that the gum disease bacterium Por’phyromonas gingivalis is behind a range of diseases. (10 August, p 42)
When I was growing up in the 1950s, many believed that decayed teeth served as 鈥渟eptic foci鈥�, spreading disease throughout the body. I remember several advertisements for toothpastes and mouthwashes that played on this fear. Dentists usually removed decaying teeth as a precautionary measure instead of trying to conserve them.
Then it was declared that bad teeth were just bad teeth and there was no such thing as a septic focus. The idea dwindled into pseudoscience. Is it back?
I was a climate change denier but I got better
Lucia Singer refers to her teenage concerns about global warming in the 1980s and the existence even then of deniers, who nowadays attribute the undeniable warming to natural fluctuations. (Letters, 13 July)
Sadly, I was at the time one of those instinctive deniers. Being professor of ocean engineering at Newcastle University and a reader of voluminous reports on deep-sea drilling projects that referred to past climate variability, instead of just ignorantly sniping from the bushes, I set about trying to prove my point. This is how I failed.
Among those reports, one interpreted global temperature changes over the past 7 million years from cores taken from the Atlantic seabed. A diagram in it seemed to show a sinusoidal variation with a period of 4.8 million years, and variations with successively smaller amplitudes and periods of 2.4 and 1.2 million years. I was hooked.
I discovered hundreds of references to proxy-temperature variations, ranging from billions of years down to the most recent hundred or so years. All showed the same summation of sinusoidal curves with halving period and reducing amplitude.
I built a simple model based on those sinusoidal curves (see ). Then I compared it with the temperatures measured since instruments were available. This showed global temperature consistently increasing above the model’s forecast. I could explain the difference only by adding human-made heating 鈥� of about 3掳C for every doubling of carbon dioxide equivalent. I ate humble pie in 1984 and have remained a convert ever since.
In 2009, after several years of global cooling, my model forecast the precise scale of warming in the middle of this decade 鈥� and the pause in warming since. It forecasts this to continue until about 2030 with accelerating and unstoppable temperature rise after that. I would be delighted to have my model proved wrong. I don’t want to fry.
Looking on the bright side of a large seaweed patch
You report the detection by satellites of a giant seaweed patch stretching from West Africa to the Gulf of Mexico (13 July, p 17). This should be seen as good news. It is taking up nutrients and fertiliser run-off from the land and turning them, with minerals that are dissolved in seawater, into the best compost and soil conditioner I know of.
Farmers in Malta and elsewhere have collected seaweed for centuries in order to create new soil and replenish the old. Farming practices throughout the world tend to result in increased erosion and loss of soil quality. There should be ships gathering up this bounty to replace the tired, mineral-deficient soils being washed into the sea.
Not everyone depends on thinking in language
David Werdegar asserts we have an 鈥渁bsolute dependency on the signs and symbols of language鈥� (Letters, 20 July). That is questionable: not everybody thinks in the same way.
Composers clearly think in musical terms that are sometimes difficult if not impossible to verbalise. Roger Penrose, in his 1989 book , uses his own experience, and that of other distinguished scientists, to argue that much scientific and mathematical thought is non-verbal.
More on mapping time and language to space
Phil Ball suggests that Mandarin speakers think of the future as down because it matches their direction of writing (Letters, 27 July). Even if such a correlation is found across all writing systems, it could equally be that the mapping of time to space came first.
Spatial mappings can arise where there is no writing. The Yupno of Papua New Guinea conceive the future as uphill, while for the Aymara of the Andes it is behind one, with the past in front, perhaps on the basis that the past is known, the future unknown (2 June 2012, p 14).
The far right recycles its ideas efficiently
I enjoyed Graham Lawton’s article on the exploitation of environmental language by the far right (17 August, p 24). I take exception, though, to the idea that this has only recently emerged. Far-right politicians have often linked notions of nationhood and the environment.
This was particularly evident in the 1930s, when some Nazis in Germany used the idea of a Volk embedded within an environment supposedly peculiar to a particular race. So this is another example of the ability of the far right to do its own dispiriting sort of recycling.
I see downsides of drawing water from the desert air
Attempts to draw water from the air, and especially the use of metal organic frameworks with their non-intuitive properties, are interesting (3 August, p 38). But what is going to happen to flora, fauna and down-wind weather patterns if large amounts of moisture are pulled from the atmosphere in already arid environments?
Please get in touch if you were on the Maths Bus
Sue Armstrong reported nearly a quarter of a century ago on the Maths Bus that toured South Africa (3 September 1994, p 6). Some of your readers were attracted to this educational project and volunteered on and supported the bus. I ask them to get in touch through 快猫短视频.
Some obstacles to building better hearing aids
Alan Gordon suggests hearing aids should replicate the directionality given by the shape of the ear (Letters, 27 July). Most manufacturers use test equipment called a Head and Torso Simulator. This can be fitted with external ears to test the idea. It ought to work. I haven’t yet tried it myself, but I might be able to in the near future.
My guess is that it doesn’t work very well. If it does work, it isn’t easy to see how to make its appearance acceptable, especially as hearing-aid manufacturers try to convince people that the aids should be as near to invisible as possible. This is despite it increasing costs and compromising performance. By the way, I’m nearly 82 and am still able to work on things to help people hear.
We are halfway to a carbon sequestration solution
Butch Dalrymple Smith says we should plant trees and make things out of wood to sequester carbon (Letters, 3 August). We are already doing half the job by farming trees to make paper and chipboard. When we have finished with them we recycle or destroy them.
Why not preserve the paper and chipboard as a way of storing carbon? We would need to package it to prevent decomposition. How about baling the paper and then coating it in plastic? We have lots of waste plastic to recycle for that.
Slime, slime, glorious healing slug slime
Leah Crane reports work on using salamander mucus to help heal wounds (15 June, p 19). This reminded me of the time my father gashed himself while working on a motorbike engine. As someone whose pharmacy training was interrupted by a spell as ground crew in the air force, he knew a remedy used in the 1920s, and dispatched me to find a large slug. This he squeezed to make it exude the slime that he found to be healing for the wound.
I have never found the need to repeat this treatment on myself. I am surprised that Harvard Medical School has discovered the same phenomenon in Chinese salamanders.
A surprising part of Gaia's self-correcting strategy
After reading your recent article on the Gaia hypothesis, I wondered whether anyone had considered that the human species may be a solution to one of the biggest threats facing Gaia (10 August, p 13).
It seems that humans have just the right amounts of aggression and intelligence to create things that could alter the trajectory of an incoming asteroid that is capable of causing a mass extinction.
The last one of these was quite bad and the next could be worse. It would be a risky strategy on Gaia’s part, but if the species also enables life to be established on a second planet that would improve the long-term odds of life’s survival.
Such a cool word deserves to be used
Chelsea Whyte writes of moons ejected from their orbits around exoplanets, called 鈥減loonets鈥�. (13 July, p 15)
She mentions the slow drift in our moon’s orbit and the possibility that this might be its fate. Would this make it a 鈥減rotoploonet”? That is such a cool word that it deserves to be used.
For the record 鈥� 31 August 2019
鈥� The common name of Protonibea diacanthus is the blackspotted croaker (1 October 2016, p 16).