Letters archive

Former UK government adviser Simon Sharpe is dismissive of carbon taxes as a means of tackling the climate crisis, instead urging investment "in new technologies and new systems" ( 30 September, p 37 ). But these aren't mutually exclusive. He himself says that we need "investment in targeted subsidies so that these solutions can take …

In his call to rethink how climate policy is communicated to policy-makers, Sharpe fails to mention the integrated assessment models (IAMs) that have underpinned Intergovernmental Panel on Climate Change reporting to governments for three decades. These are technology focused and highly dynamic. They track the unit cost of existing technologies against uptake, assess speculative technologies …

I agree that new AIs have shortcomings. When I asked ChatGPT to write a story in the style of Agatha Christie, it wrote pages of frighteningly realistic text until it broke the most basic rule of crime writing: it told me that it was the gardener who did it ( 7 October, p 20 ). …

You report on a study that predicts nearly all mammals will go extinct in 250 million years as continents recombine and the climate shifts ( 30 September, p 9 ). However, I assume that the changes will occur so slowly as to allow considerable time for evolution. Humans may be long gone, but, as a …

Researcher Alexander Farnsworth anticipates that, due to natural processes, atmospheric carbon dioxide will reach levels incompatible with mammalian survival in a quarter of a billion years. He hopes that "we'd be a space-faring civilisation by that point". But the technical challenges in managing atmospheric CO 2 levels are trivial compared with those of human interplanetary …

Concern over China's carbon emissions misses a key point. In the 1950s, when vehicle use was really beginning to take off, British models were made from steel produced domestically and from locally mined iron ore and coal ( 7 October, p 12 ). Now, the same car could be made from ore and coal mined …

I offer further arguments against the existence of free will. First of all, two of the greatest minds to have ever lived, Bertrand Russell and Albert Einstein, scoffed at the very existence of free will ( 30 September, p 32 ). Secondly, many parents of more than one child will attest to how different their …

Are the forces of evolution so powerful and compelling that they negate free will? Or are they so powerful and compelling that they create free will? Either you have no choice or you have no choice but to have choice.

Your fascinating article about deciphering historical documents written in code made me wonder where the code-breaking sources that must have been needed by the senders and recipients of these documents are ( 23 September, p 40 ). Have none been found? No worksheets where recipients struggled to "translate" what they were given? Are there no …

Thank you for putting aside the hyperbolic, catchy factoids on the gut microbiome to give clear comment. There are trillions of residents in our colons, but we are still in the very early stages of defining which microbial make-ups are better or worse ( 7 October, p 30 ). Greater microbial diversity appears to be …