Letters archive

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 …

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 …

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 “septic foci”, spreading disease throughout the body. I remember several advertisements for toothpastes and mouthwashes that …

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 …

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?

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 …

• The common name of Protonibea diacanthus is the blackspotted croaker ( 1 October 2016, p 16 ).

Clare Wilson does a good job revealing the pitfalls of most studies looking at diets ( 13 July, p 32 ). She could also have mentioned the emerging discoveries of the health effects of the composition of our microbiome – the organisms in our gut and on our skin, for example. Perhaps knowledge of how …

Wilson correctly points out the limitations and inconsistencies of observational studies based on questionnaires, and the inability to perform randomised controlled studies of diet and health. She concludes that the problem is serious enough that we should be sceptical of all dietary advice. But there are studies that examine health differences in geographical populations with …

In her excellent article, Leah Crane mentions that the atmosphere of Venus “inexplicably rotates 60 times faster than the solid planet” ( 22 June, p 42 ). We first learned of this implausible phenomenon in the 1960s when Desmond King-Hele discovered that Earth's atmosphere rotates up to 50 per cent faster about 370 kilometres up …