Letters archive

In coverage of the direct air capture industry, you mention a plant being built to remove half a million tonnes of carbon dioxide per year from the atmosphere. This apparently impressive figure needs context ( 25 May, p 12 ). In my youth, the colliery in my village was producing a million tonnes of coal …

It isn't surprising that there has been criticism of the idea that humans evolved to chase down prey over large distances. The need to do this regularly would suggest an inability to hunt strategically or co-operate with others, which is somewhat insulting to the developing human intelligence ( 18 May, p 11 ). Sensible strategies …

Thank you for your look at the ageing mindset. Although, at least according to this, I am already at the age when people start to acknowledge that they are old, I certainly don't feel that way ( 18 May, p 32 ). Maybe that is due in part to having a wide circle of friends, …

Your article reminds us not to stereotype all older people as frail, lonely or incapable. Ageism is one of many forms of labelling. Any group is in danger of that. It can serve a purpose by making us alert to specific needs, like offering an older person a seat on public transport. But when meeting …

Your report that farmed pigs appear to find life less of a struggle when they can smell a pleasant odour is frankly sickening to read ( 18 May, p 14 ). This farming is undoubtedly for pork production, where young pigs are castrated, overcrowded and have no access to exercise in the natural world. These …

Like Graham Lawton, my views on offsets to balance carbon emissions from flying evolved from interest to scepticism. How do we know these programmes have substantive, long-lasting impacts? We don't ( 11 May, p 22 ). However, there may be a more effective solution than either not flying or waiting for offset programmes to prove …

I applaud Lawton for outing flight offsetting programmes as greenwashing. As many of these projects are fairly obscure and the market for carbon credits is equally murky, consumers are put off any form of offsetting, which is also a problem. Similarly, many people are stuck with an oil or gas boiler and a petrol or …

May I add an additional consideration to the debate about LED street lighting? In the days of sodium lamps, it wasn't unusual to fail to notice an amber traffic light among the street lamps. This was exacerbated if the shape of the road and height of the lamps meant that the traffic light appeared to …

In my view, the ultimate source of civilisation-ending events, of the sort detailed in your look at the downfall of eastern Mediterranean Bronze Age societies, is invariably drastic climate change. As your article says, "so much chaos, simultaneously, is surely no coincidence", and while clear-cut evidence for climate catastrophe is currently lacking, so are any …

So cosmology may now need "dark radiation" as well as dark matter and dark energy. But the only reason these three imaginary fiddle factors are required to make observational data fit the standard cosmological model is because gravity is assumed to be constant everywhere ( 18 May, p 8 ). When you have to imagine …