Editor's pick: My heat pump needs permission to chill
Michael Le Page says an important part of reducing the contribution of household heating to climate change is to install heat pumps, powered by clean electricity, in rural and suburban areas (17 November 2018, p 22). I see very little effort to promote these. I got my heat pump from a firm that cold-called me, the only way I was made aware of their availability without having to search.
It is possible to get most of the power to run it from solar panels. It keeps the house warm on less than 1 kilowatt most of the time, rising to 1.5 kilowatts in very cold weather. A conventional electric heater wouldn't keep one room warm on this power.
A neighbour, who has since moved, complained that I had installed an “air conditioner” without consent. The local authority let me keep it: used for heating it is “permitted development”, but I if I were to use it to cool the house. Now my street has been declared a “conservation area” and it seems new heat pumps here will need permission, which I suspect I wouldn't easily get.
Get engaged to confront the climate crisis
Thank you for addressing the most critical threat to our long-term survival: global warming and climate disruption (8 December 2018, p 31). Each step described is important to reduce carbon emissions.
But how can we bridge the gap between being aware of the problem and taking the system-wide steps needed to address it? How to build the political will to make the changes we need in order to survive?
What is a concerned reader to do? Somehow waiting for a “mass movement” to develop seems too passive, weak and iffy in light of the gravity of the problem.
I urge everyone who cares about this issue to join one or more of the many excellent organisations that are working on the problem. Give them time, energy, ideas and money as you can. Talk with friends, family and political representatives about your concerns and your commitment. Joining others working on global warming and climate disruption can build a community and multiply our efforts.
First class post 鈥� 19 January 2019
AI still can't figure out how to tell the difference between black people though
Woke bae of pigs in artificial intelligence identifying genetic disorders by the shape of someone's face (12 January, p 15)
You'd need wall-to-wall beavers to dam floods
Graham Lawton says beavers at a site in Devon, UK, have a huge impact on flood management there by building dams that can store and slow the release of water (22/29 December 2018, p 10). But Richard Brazier, a lead scientist behind the reintroduction project that Lawton visited, .
Onno Bokhove and colleagues calculated that about 8500 beaver colonies would have been needed along parts of the River Aire in West Yorkshire, UK, to have coped with the Boxing Day floods of 2015 (EarthArXiv, ). This would be interesting to see – with so few trees available, maybe they could use plastic rubbish for their dams, solving another issue?
Beavers are lovely in themselves and we should celebrate their reintroduction, but let's not get carried away and encourage government to think they are a cheap flood prevention solution.
We just need to get on with electric vehicles (1)
Rob Cannell reiterates doubts about the ecological benefits of electric vehicles (EV) because of the proportion of electricity from burning fossil fuels that currently powers them (Letters, 8 December 2018). But anyone who has driven an EV will regard a car powered by an internal combustion engine as positively agricultural, whether fuelled by petrol, diesel or liquid petroleum gas. As electric vehicle prices fall, as they inevitably will, the real motivation for their roll-out, which is driver demand, will accelerate. The energy supply industry needs to keep pace and the government needs to start to transfer subsidies away from fossil fuels and towards renewable energy generation and storage.
We just need to get on with electric vehicles (2)
Cannell mentions the benefits of running vehicles on liquid petroleum gas (LPG). It does produce less nitrous oxide and other pollutants and is less carbon intensive than petrol/gasoline. But this gain is more than countered by the low efficiency of a small internal combustion engine (20 per cent) compared with burning fuel for electricity generation (around 37 per cent for coal and 62 per cent for combined-cycle gas) to charge electric cars. And there isn't enough LPG in crude oil for it to be a significant replacement for petrol and diesel.
Navigation is odd when you're upside down (1)
Emma Young's article on human navigation prompted me to reflect on my own ability (15 December 2018, p 38). After living for 35 years south of the equator and easily navigating around unfamiliar locations in New Zealand and Australia, I was perplexed at discovering it nearly impossible to find my way around London, even with a map. I found I was able to regain a sense of direction by rotating my map with south upward. This method was also useful in later visits to cities, forest and open countryside in Europe and North America. What directional cue may I have been sensing: magnetic field or polarised light?
Navigation is odd when you're upside down (2)
While my wife Roslyn and I rarely become lost in New South Wales, a trip to Hawaii demonstrated that we use different means to navigate. I consistently turned north when I meant to turn south and swore blind that I was going in the right direction while my wife indicated the opposite direction, and was correct. I concluded that I was unconsciously navigating by the sun, turning in the correct direction for the southern hemisphere, while Roslyn was navigating by landmarks.
Autonomous cars as a boon for elderly people
There have been extensive discussions of the pros and cons of autonomous vehicles (for example Letters, 17 November 2018). But I have seen no mention of their use by elderly people. When issues with such vehicles are effectively solved, car travel will be as safe and as easy for the old as for others. In countries with an ageing population and a dearth of public transport outside the city cores, this will be a benefit.
A pilot's job is to fly the plane when it goes awry
Peter Lemme is right to ask where the division of responsibility lies between automated aviation systems and pilots, and right to conclude that pilots should be ready and able to take over (22/29 December 2018, p 24). I would add that “able” means no aircraft should prevent the pilot taking control, and “ready” means that pilots should be properly trained to do more than just operate the on-board computers.
Pilots of automated aircraft must maintain awareness of such simple things as the aircraft's attitude and air speed, so that they know when to take control. The basic instruments for this are altimeter, rate-of-turn indicator, artificial horizon, and air speed indicator. We should be asking about aircraft that don't permit the pilot to take control easily, about pilot training and cockpit awareness, and about making sure that there is no skimping on flying-the-plane training.
An underwhelming feat of engineering
You report that a tyre recovering electrical energy could save 800 kilojoules a year (8 December 2018, p 19). You could have knocked me down with a motor car! That's kilowatt-hours, which is the energy in litres of petrol.
Musk's satellite scheme is not so strange
Karen Hinchley asks whether Elon Musk will retrieve and recycle obsolete satellites in his plan to provide internet access from orbit (Letters, 1 December 2018). These satellites would be in low Earth orbits and would eventually burn up. On the same page, Robert Hill notes that keeping 4425 working satellites in orbit may require launching 17 a week. A month's worth .
Predictive policing is a self-fulfilling prophecy
Chris Baraniuk reports UK police plans to use machine learning to predict criminal behaviour and offer interventions (1 December 2018, p 6). It seems that the system was trained on databases including information unrelated to court findings of guilt, such as police stops, searches and crime reports. I expect it will lead to more arrests, including some for disorderly behaviour by “offenders” shouting “why do you keep apprehending me and offering counselling?”.
Large moons are still significant for evolution
Eric Kvaalen notes the sun's contribution to tides on Earth (Letters, 15 December 2018), in response to my letter on the importance of lunar tides to life moving from the oceans to land (3 November 2018). With respect, I didn't suggest that there would be no tides on Earth without our large moon. But the moon is the major determinant of our tides.
Large tides may have allowed life to move onto land despite the advantages of the ocean: narrower temperature range, no risk of dehydration, little need for strong skeletons, and so on. If we ever do find intelligent life elsewhere, I still predict it will be aquatic.
For the record 鈥� 19 January 2019
• Cave bears died out around the last glacial period within the recent ice age (22/29 December 2018, p 54).
• The photo used to illustrate frost flowers was of hair ice, which exudes from logs. Water is more likely to supercool if particulate impurities are absent (22/29 December 2018, p 52).