Letters archive

Your recent analysis of the potential wider use of direct air capture to remove carbon dioxide from the air is right to be circumspect about its prospects. This would be the most expensive, inefficient and convoluted way to avoid climate change ( 25 May, p 12 ).

I started using low-sodium "heart" salt about four months ago, having read about its effect on reducing blood pressure. I am in my 70s and I have regular blood tests. After a test five weeks ago, my doctor was concerned about high potassium levels in my blood, so I told him what I had been …

Jim McHardy suggests that advanced civilisations won't need Dyson-style, whole-star, solar energy-collection structures because they will have minimised their energy consumption ( Letters, 8 June ). But as far as we know, creating or accelerating matter requires a non-negotiable amount of energy (given by E = mc 2 and E = ½ mv 2 , …

From 15 June, p 19 It is amazing that there are still doubts about whether human newborns are conscious and capable of experiencing pain. Newborn foals and calves are born with their eyes open and are capable of walking almost immediately after birth. I have been at the birth of several spectacled flying foxes, amazing …

I can't believe that scientists are conducting experiments to find out what every parent has known since the dawn of humanity, the moment they look in their baby's eyes just seconds after it takes its first breath: there is someone there. An ignorant, inexperienced, inarticulate someone, to be sure, but a person ready to be …

From 8 June, p 15 So sulphur dioxide emissions from ships burning heavy marine fuel cooled Earth by brightening ocean clouds, but declines in such pollution since 2020 have resulted in warming. This unplanned experiment in geoengineering indicates that we should now fund tests of marine cloud brightening using ships to spray seawater into clouds …

From 25 May, p 36 Having read your piece about how to measure biodiversity, it is worth remembering that although the species concept is immensely useful, it does have its limits. This is because species descriptions, in order to be practical, have to encompass a lot of variation between individuals, both in their outward characteristics …

From 22 June, p 16 I was heartened to read of another organism that has taken to consuming one of our throwaway polymers. To be fair, given the high energy density of plastics, it isn't surprising that microbes are evolving to feed on them. I agree with Annika Vaksmaa about the dangers of introducing this …

From 15 June, p 28 I take issue with claims that scientists are fairly unanimous that drinking alcohol in moderation is healthy. While I agree that this is preferable to excessive drinking, there is no amount of alcohol consumption that doesn't affect health. In fact, the World Health Organization published a statement on this in …

From Letters, 22 June There is some misunderstanding about interference in the double-slit experiment. The electron doesn't interfere with the next electron, but with itself.