Letters archive

Record-breaking temperatures in the air and oceans highlight two extremely urgent challenges ( 1 June, p 8 ). Despite the Paris deal for a 1.5°C warming limit and undertakings at subsequent COP meetings, total energy-related annual carbon dioxide emissions continue to rise, approaching 37 gigatonnes in 2023. Drastic action to reduce our dependence on fossil …

Your intriguing article about retrocausality poses the question of whether quantum information could be sent back in time. Surely the answer must be yes. How else could we explain the fact that electrons sent through a double slit, one at a time, create an interference pattern on a screen beyond? Each electron must be sending …

You report that time could be a quantum illusion. Maybe it is the other way round. Perhaps space-time is fundamental and the simplest way a universe with time can be predictable, but not deterministic, is for it to obey the rules of quantum mechanics.

Yes, there is a problem with salt addiction, but it is social rather than biological. A liking for salty food is far from universal and is probably acquired rather than innate. In family homes and in restaurants, the salt shaker is a ubiquitous presence on the table. Many people add salt to their food before …

Alex Wilkins's review of books on artificial intelligence mentions Ray Kurzweil's prediction that the Turing test of machine intelligence will be passed by 2029, along with his belief that the singularity – when AI will surpass human intelligence – is nigh ( 1 June, p 28 ). I don't think this is just a question …

James Wong needn't choose between drinking milk or using it as a plant fertiliser. Drink the milk, then, a few hours later, you can be fertilising plants with it – possibly in a way that makes it easier for the minerals etc. to be assimilated, especially if your efflux is diluted with soft water ( …

Graham Lawton delved into the many benefits of using wood in construction beyond its ability to store carbon, and I can vouch for some. Years ago, I designed an award-winning school using Japanese-style hybrid-timber construction, including a laminated timber frame with solid-timber decking ( 8 June, p 24 ). The real reason for the choice …

In your interview with Sophie Attwood, it was good to read about the simplicity of effective interventions to modify our unsustainable eating habits. However, the final quote that "8 billion people are eating three meals a day" is debatable ( 1 June, p 37 ). According to a recent UN report, close to a billion …

Even if we ignore the various technical doubts about carbon offsetting, whether offsetting a flight makes flying acceptable depends upon what activity you think of as coming first ( 11 May, p 22 ). The usual view is that the climate-negative activity of flying is being compensated for by offsetting. But an alternative view is …

Your review of the book Eruption got me wondering if it is possible to dump anything into an erupting volcano? Could, say, landfill waste be disposed of in the gaping "incinerator"( 8 June, p 30 )?