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Are we really going to store thousands of gigatonnes of carbon dioxide in geological formations? There are real doubts about whether the required technology will become sufficiently developed and whether the energy needed for it would be available. At present, only a few million tonnes per year are being pumped underground and much of this …

Some views on global warming targets reveal a continuing fantasy: the belief that any such target is achievable without climate engineering. Nobody, their governments included, is going to tell people in low-income countries that they can't have air conditioning or cars (or toasters, microwave ovens, etc.). Global warming is unstoppable, and the adverse consequences will …

Drilling through polar ice to pump out liquid water from beneath won't work for several reasons that weren't mentioned. At the depths and temperatures of the buried water, it is close to the equilibrium between being ice or water. A slight change could drive it either way. Water, whether in an artesian well or pumped …

When astronomers say that, sooner or later, we will come across an exoplanet with a nitrogen/oxygen-rich atmosphere, or that, by 2060, we are likely to have discovered planets where it is hard to explain the data without there being life, they are assuming, with no good reason, that life can easily arise if the conditions …

I have read your fascinating article on the phenomenon of superluminal shadows in astronomical contexts. It is truly captivating to explore these cosmic curiosities. However, I would like to point out that apparent superluminal motion isn't just confined to the depths of space( 27 September, p 42 ). Engineering equipment capable of demonstrating similar effects …

In your look at how to live to 100, Bryan Johnson states that he doesn't need to worry about how long he will live because it won't be long before he can upload himself to an AI( 20 September, p 40 ). This is, of course, massively optimistic, requiring not only the technology, but also …

Why was there no mention of posture in "How to live to 100"? The typical depiction of older people is of someone bent over while using a walking stick, but good, upright posture aids breathing and mobility, and helps to avoid injuries when exercising.

I concur with Robert Sugden's views. As an otrovert, I find no particular attraction in interacting with others solely because they are also otroverts. Interesting conversations come from people with different points of view. I am Russell's paradox, part of a set that doesn't include myself( Letters, 13 September ).

David Robson's article on narcissism is enlightening and a reminder that we can all get carried away with trying to appear cleverer than we are. But the final paragraph sidesteps the elephant in the room: we may well be better off without narcissists, but when we grant them power, they destroy lives and economies. Avoiding …

Congratulations! An article about narcissists without mention of a certain president!