‘Reflecting sunlight would give us more time to convert energy systems’: Your letters to Professional Engineering

On reflection

Denis Oglesby has the right idea in recommending systems to reflect incoming sunlight. We can do that and it would counteract the partial absorption of the outgoing radiation caused by excessive CO₂. It would give us more time to convert energy systems to renewable and sensible nuclear (like Moltex). Our current trajectory is hopelessly inadequate and the yearly increase in our requirement is greater than the rate of building of renewables.

However, I suggest that bright cloud is also a promising way to reflect incoming radiation. It can be made quite easily, simply by putting aerosol particles of ammonium sulphide (a food additive) into the atmosphere in the 5-10% areas of the ocean most susceptible to cloud brightening. The right-sized particles attract molecules of water to form bright cloud. Leveraging cloud reflectivity this way provides an enormous cooling return on investment.

The technology is known and the late Dr Stephen Salter worked out a lot of the practical details. He wanted to present his ideas to COP26 in Edinburgh in 2021, but was not even allowed to attend. The politicians had made up their minds and did not want to be confused by the facts. I hope that engineers are more pragmatic in their approach. Opponents call it geoengineering, but it is on a minuscule scale compared with the massive scale of the geoengineering [greenhouse gas-caused climate change] that we are doing all the time.

Marine cloud brightening could be deployed quickly and, in the unlikely event that it has some unforeseen adverse side effect, it can be stopped quickly because the clouds disperse naturally, within about two weeks.

IMechE should put its shoulder behind the practical idea of countering global warming by marine cloud brightening so our grandchildren can expect to enjoy the sort of life span we are enjoying.

Jim Elsworth, Tanzania

Chasing status

In the words of Albert Hammond from 1973: “Well, they used to sit and speculate upon their son’s career, a lawyer or a doctor or a civil engineer.” 

While it was gratifying (if unsurprising) to read in Matt Garside’s interview that engineering is a highly trusted profession, the depressing takeaway from his comment is that engineering was only included as a profession in 2018! This says everything about the status of engineers in UK society, as compared with the US and elsewhere. 

I first joined IMechE as an MPDS student in 1976, and I’m not sure the status dial has moved much since then.

Simon Glover, CEng, FIMechE, New Zealand

Lightbulb moment

Could this enable cost savings in the building industry? Some time ago, I bought a set of remote-controlled electrical socket-switches. I find these useful to power TVs, washing machines, etc, without struggling to access sockets in awkward corners of the room. 

For those not familiar with these devices, each unit is a ‘through socket’, i.e. an integrated three-pin plug/socket incorporating a radio-operated switch linked to a portable remote control. It’s possible to have up to four sockets switchable by this small remote control unit. They perform the task efficiently and were bought at very modest cost. I use them in the living room, kitchen and utility room. It occurred to me that an electrical fittings manufacturer could adapt the principle to operate domestic lighting and that, if so, there would be considerable savings, especially for new-build homes and extensions to existing homes, as follows.

During the electrical installation in the build process, the mains feed to the centre light (or LED cluster) in each room would incorporate a radio sensor similar to that of the through socket described above. The light circuit would be switchable by the remote control unit and there would be no need to run a live switch cable down from the ceiling of the room. Obviously, less labour would be involved. The position (and number) of the ‘light switches’ would be flexible depending on the initial room layout, and subsequent building changes could take place with minimal disruption to the circuit. Also, for domestic bathrooms there would be no need for ‘pull switches’ as the remote control units would be battery-operated.

Some product development would be required, battery life/accessibility, prevention of cross-talk (switching your neighbour’s lights off!), etc, would need to be addressed, but not withstanding I believe there could be advantages.

The building industry is not my direct area of expertise and perhaps similar units are already developed and ready to go. If the idea has some virtue, however, I would be grateful for comments from other readers.

FT Murphy, member