Letters archive

Urban trees planted in Stockholm, Sweden, have been shown to be healthy, and the methods used are now being applied in the UK with growing success. The Stockholm Tree Pit system captures rainwater from roofs and roads, then channels it into a tree pit containing crushed granite and biochar. This allows for ingress of both …

Fallen leaves from urban trees are often swept up and disposed of by street cleaners or residents, removing a valuable source of leaf litter, which forms the top layer of soil in forests or woodland. Returning this as a mulch, in addition to added topsoil, could help solve some of the problems you report. In …

Hayaatun Sillem is correct in her assessment of the shortage of graduates in engineering ( 28 October, p 21 ). The lack of women in this walk of life is a problem that has consumed a forest full of research papers and focus group reports over the years, but to little effect. It isn't simply …

Why so much cynicism over "ultra-processed" foods (UPFs)? You report claims that the food industry's goal "is to maximise profits by cajoling consumers to abandon freshly prepared food". Why not say that the industry gives us the possibility of buying ready-to-eat food instead of having to do all the processing ourselves? And why say "they …

Perhaps there is no more ultra-processed food than lab-grown meat and plant-based alternatives.

You rightly laud South Australia's push to decarbonise its electricity generation, but, in common with so much reporting around net zero, the implication is that we will hit this target when all of our electricity generation is carbon-free. Global primary energy consumption in 2022 was around 179,000 terawatt-hours, of which about 137,000 TWh, or 82 …

S. W. Shaw calculates that around 9 million UK homes may have converted to using heat pumps in the next 15 years. However, millions of homes here are Victorian and broadly aren't suitable for heat pumps . Beyond those 9 million conversions, to really make progress towards net-zero housing, we may have to bulldoze all …

There have been welcome ideas from readers relating to carbon taxes, but an important added ingredient is needed to make them work, to prevent "carbon leakage" via the import of goods with high embedded carbon ( Letters, 21 October ). To that end, the European Union has created the Carbon Border Adjustment Mechanism (CBAM). It …

I am concerned about the impression that discarded toys generate more e-waste than vapes. While it is true that toys make up the majority of this in landfill, I suspect vapes make up the majority outside landfill and fly-tipping sites. Some ex-smokers discard them like cigarette butts ( 21 October, p 14 ).

You raise the idea that there may be a harder core to the Great Sphinx of Giza, the shape of which was formed by wind erosion ( 4 November, p 13 ). Couldn't this question be easily answered by the use of ground penetrating radar? If there is no hard core, then the riddle remains!