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You highlight problems with the growing demand for energy-intensive air conditioning in a warming world. How about updating building regulations so that new air conditioning installations must be accompanied by solar panels? Peak cooling demand (and electricity consumption) can be expected to correlate with daytime maximum solar radiation and maximum solar panel output ( 6 …

I resonated strongly with Harvey Whitehouse's point that "if we are to mature into a global tribe, capable of solving global problems, we will also need leaders capable of crossing existing tribal divisions", and that this requires "ways that are grounded in science" to address our collective interests ( 22 June, p 36 ). I …

Our climate and biodiversity woes represent a threat greater than a world war. As we would with such a conflict, we need to spend our resources wisely on projects that will reap rewards immediately, or at least within the 20 years or so we have to make the biggest impact ( 6 July, p 13 …

The cool fabric for clothing that you describe may be rewarding for the scientists who designed it, but could it be damaging to the environment? Its three layers – wool or cotton, silver nanowires and polymethylpentene – could be a nightmare to recycle, particularly as many people wear fashionable items for a short period and …

I take issue with Dan Roach's assertion that there is no safe level of alcohol consumption. You could equally make the case that there is no safe level of driving or playing football or swimming. Perhaps there is no safe level of being alive, given it always seems to end badly ( Letters, 6 July …

I have an idea related to David Robson's look at scientific rules of connection that could improve your social life. One way for pubs, parks, libraries and other social spaces to help would be to paint a large red dot on the ground. This would be a place where people who want to develop new …

Having watched the first two A Quiet Place films, and reading Douglas Vakoch's lament about the irrational fears raised by the portrayal of scary extraterrestrials in the third film, I wonder if I am alone in believing these blind movie aliens aren't even remotely likely? Sharp-eared enough to hear a picture frame smash a mile …

The underlying debate is whether it is a good idea to send signals to try to reach intelligent aliens. The worry is there is no global entity that polices such transmissions and, even if there were, it would be impossible to enforce. But I agree with Vakoch that it doesn't matter because aliens advanced enough …

Bringing back the dodo might have commercial implications because it was apparently tasty to eat. I can imagine meat producers being interested in an edible bird twice the size of a turkey, especially if its growth or reproduction rates could be tweaked ( 15 June, p 40 ).

As I see it, to replace a lot of fossil fuel use requires a chemical that would react, for example with water, to produce hydrogen on demand. A driver could go to a fuel station with a spent pack of this chemical, buy a new one and fit it in place and drive off in …