Letters archive

In your article reporting work by climate scientist James Hansen, he points out the risk of sudden sea level rise due to tidewater glaciers collapsing in decades rather than centuries ( 1 August, p 9 ). His work has been criticised, but most of his critics don't understand the distinction between melt and collapse. They …

Michel Odent raises some interesting questions around whether some women might find childbirth easier "in a small, dark, warm room, with... one midwife... knitting" ( 4 July, p 26 ). I would be interested to read any evidence supporting his theory, that women's capacity to give birth is repressed by neocortical activity, one source of …

Bad news should come from a person in a supportive environment, not a strip of plastic Marie Ayres responds to our report of a test kit that could predict miscarriage ( 15 August, p 13 )

You report concerns that an advice leaflet for pregnant women spells out the risks of caesarean sections while it avoids mention of the risks of vaginal birth ( 25 July, p 5 ). But the World Health Organization has stated that there is no health improvement for either mother or baby when C-sections exceed 10 …

• The WHO's position is contested, because of a lack of evidence that lower C-section rates are linked with lower mortality; in fact, countries with higher C-section rates have lower mortality. Aiming for vaginal birth may lead to an emergency C-section, which has much higher risks than either a planned C-section or a vaginal birth.

It is still the general feeling in obstetric practice that a caesarean section poses certain risks to the mother but relatively few to the baby. However, choosing to surgically remove a baby from the uterus might carry with it some long-term problems. The baby misses out on the physiological environment created by natural labour: the …

Your article on developments in battery technology was timely. ( 25 July, p 20 ). In the same issue your interview with Malte Jansen about German progress towards 100 per cent renewable power ( p 17 ) surely made any Briton long for a UK energy policy with substance. However, it must be stressed that …

Malte Jansen seems proud of the fact that by 2050 Germany will reach the same level of clean electricity production with renewables that France achieved in about 15 years with nuclear. I thought climate change was an urgent problem? St Morris, South Australia

• We asked Malte Jansen about nuclear power, but his answer was cut for space. He said that the process of digging uranium ore and making fuel rods is itself highly energy intensive, and since nuclear plants can't be turned rapidly on and off, they hinder the integration of renewable sources.

Paul Younger writes that energy security seems to have been "forgotten" by those who oppose fracking for shale gas in the UK ( 11 July, p 24 ). Unfortunately, the article perpetuates the myth that reducing fuel imports automatically improves energy security. Energy security is a complex issue and cannot be simplified to metrics such …

Robert Gifford missed one of the family of "dragons" that stop people thinking about climate change ( 11 July, p 28 ). It is fear of big government. The "logic" goes like this: climate change is a large-scale problem. The only institution big enough to tackle a problem on this scale is government. If you …

Clare Wilson presents the fascinating fact that the action of the diabetes drug metformin contributes to a longer life ( 11 July, p 8 ). If older non-diabetics took the drug, they too could benefit from a lower incidence of heart disease and cancer. Great! What isn't mentioned, however, is that metformin has been linked …

In your article "Slime-mould economics" you seem to express surprise that economic inequality is spiralling ( 25 July, p 38 ). But when muscle power and brainpower are being replaced by machines, it seems obvious to expect that the machines' owners will rapidly become wealthier than those whose labour is being replaced. La Ciotat, France

Anthony Castaldo says we need a "cheap solar-powered device that can produce neat carbon pellets by the megaton" (Letters, 1 August ). The machines are called trees and they store carbon in chipboard and paper. Instead of recycling or burning these products, I suggest we bale them up and cover them in thick recycled plastic …