Letters archive

You say that the biggest obstacle to progress at COP27 is the energy crisis that came after Russia's invasion of Ukraine. The invasion was an evil act, but it has had the consequence of increasing fossil fuel costs, raising incentives for energy efficiency and saving, insulation and so on( Leader, 29 October ). Hopefully, one …

That thousands of politicians, business leaders, advisers and hangers-on are jetting to COP27 in Egypt tells us all we need to know about the chance of significant action on climate change. COP27 could have made an immediate contribution to cutting carbon emissions by moving online.

One could imagine a social aspect to the nature of reality explored in Michael Brooks's fascinating article on whether objects exist. To a great extent, human awareness of self relies on reflections of one another, in addition to the less cognitive reality around us. Perhaps all living creatures are inextricably entangled( 15 October, p 44 …

The potential for geothermal energy in the UK gives cause for optimism that this carbon-free power can be exploited. To date, the only parts of the world with electricity generated geothermally are those with active hydrothermal vents associated with volcanism, such as Iceland and New Zealand( 29 October, p 16 ). When Australia looked at …

You say that if we could tame nuclear fusion we would have a "virtually unlimited supply of clean energy". While it is true that deuterium, one of the inputs, is virtually unlimited, we would also need lithium. One estimate of how long lithium reserves would last if fusion supplied a large portion of our energy …

Amid concern over the arming of robots, I suggest that, while laser weapons shouldn't be used to deliberately blind or disable human adversaries in war, it would seem reasonable to use such weapons on robots. For a more low-cost method, a paintball pellet fired at visual sensors could do the job( 15 October, p 11 …

With reference to your article supporting the principle of solar panels on agricultural land, why don't we cover part of the roofs of large car parks with solar panels, as I saw in Italy a few years ago? As well as generating electricity, this has the added advantage of shielding vehicles - and the people …

The call to consider US-style headgear to ease head injuries in rugby isn't supported by evidence from other sports. All but one of 111 deceased former professional American football players who donated their brains for research had evidence of degenerative brain disease resulting from repetitive brain trauma ( Letters, 29 October ).

Although a seemingly sensible suggestion, helmets don't reduce the damaging intracranial motion of the brain on impact or resulting long-term cognitive effects, as the current health crisis in American football demonstrates. This is probably due to the perceived safety of the helmet leading to an increase in impact intensity and head-on-head collisions.

Sadly, I don't share Michael Le Page's optimism that the UK will eventually manage to curb carbon emissions sufficiently. Its target is based on domestic production, when it is domestic consumption that is driving big emissions both there and beyond its borders ( 29 October, p 38 ).