The food advice I needed came from a song
Your article on food advice was unintentionally very amusing (13 July, p 32). I have read 快猫短视频 from cover to cover since your first issue and have followed the changing, often conflicting, advice on food and nutrition. Since leaving boarding school, I have lived by the advice that “a little of what you fancy does you good, but too much of anything will kill you”.
I have a very varied diet and love fruit, vegetables, fish and meat, but have only a small appetite. I recently turned 80, but I am often mistaken for 60 or even younger. Another good piece of advice, taken from an old song, is “I'll eat when I'm hungry, I'll drink when I'm dry… if whisky don't kill me, I'll live till I die.”
I hope to be following 快猫短视频 for many years yet – and enjoying my food.
There are other reasons to prefer organic food (1)
James Wong considers organic food only from the viewpoint that it is said to be more nutritious (6 July, p 22). But probably the most important motivator for its consumers is to avoid the pesticide residues that industrially farmed fruit and vegetables typically contain. I don't know of there yet being a requirement anywhere to disclose the level of pesticides in food to shoppers, so the safest bet is to buy organic.
Another wider-reaching reason for buying organic food, which should be of interest to everyone whether they have a taste for pesticides or not, is that it supports traditional farming methods that have existed for millennia. As we face such a precarious future here on Earth, these methods must now be preserved at all costs for future humans to benefit from.
Organic farmers work with the soil to build and preserve its fertility, and thus increase its productivity. In contrast, industrial-scale, chemically assisted farming exploits the land relentlessly until the soil is depleted and the land eroded.
There are other reasons to prefer organic food (2)
Wong describes many reasons why analysing the nutrient composition of organic and non-organic food is difficult to do. Surely a better way to look at an organic diet would be to compare the health outcomes in groups that are made up of those who primarily consume organic food and of those who don’t?
I have rheumatoid arthritis and can report that when I eat a mainly organic diet of home-grown vegetables and organic meat and fish, my pain levels are lower and my energy levels are higher. It would be interesting to see if there is a measurable difference in things like diabetes or cardiac problems in these two groups.
Don't just plant trees, make things with them
Over and over, we hear that one of the solutions to global warming is to plant trees (20 July, p 20). Certainly, these magnificent means of pulling carbon dioxide out of the atmosphere are an essential part of our response to climate change.
But it is equally important to do something with the wood that is produced. Leaving trees to die, rot or burn returns the carbon to the atmosphere. If we build houses, furniture and boats out of wood, we not only lock all that carbon away for as long as the object exists, but also reduce the production of cement and plastics that have their own detrimental effects on the environment.
It is better to power electric vehicles with hydrogen
Electric cars are in the news again (13 July, p 18). Over the past few years, I have become concerned that people often treat battery-powered electric vehicles as a panacea. I see many problems with this.
If demand for cobalt, nickel and lithium for batteries can be met, it will cause environmental damage in places such as China, Bolivia and the Democratic Republic of the Congo. I have always suspected that the environmental cost of producing such batteries has been glossed over.
A earlier this year did try to address this. Electric vehicles should be more environmentally friendly in the long run. But the report showed that manufacturing an electric car emits twice as much carbon dioxide as its diesel counterpart. It seems that the majority of that difference the manufacture of the battery. And the issue of recycling is also yet to be fully addressed.
So I was delighted to see you discuss the potential benefits of hydrogen power (8 June, p 20). Hydrogen fuel cells are a proven technology which, unlike batteries, last for the life of the vehicle and extra energy isn't consumed to carry a heavy battery.
What on Earth would be the cost of a Mars mission?
I read Leah Crane's article on missions to Mars with great interest (15 June, p 38). But we hear little about the potential impact of rocket launches on the climate. Astronauts frequently remind us of the fragility of the atmosphere, but is sending them to space causing the damage they warn of?
Turning the space station into a business has a price
So NASA has decided to create a “commercial destination” on the International Space Station where tourists could stay in the future, with the aim of facilitating for-profit space tourism (15 June, p 5). That sounds fun: who wouldn't love to see Earth from orbit and experience weightlessness?
But the problem is that space tourism is projected to have a huge environmental impact. A thousand suborbital trips per year – peanuts compared with what NASA's plans might lead to – could result in warming of up to 1°C at Earth's poles during winter (30 October 2010, p 5). Should we subsidise another way for the irresponsible rich to accelerate the destruction of our planet? Must we actively dig our own graves?
Defeating ransomware would be easy, if only…
Chris Stokel-Walker reports that ransomware attacks are on the rise (13 July, p 9). Surely these can almost always be defeated by backing up all data securely to a computer that has no internet access? Can’t we design software that will do this automatically, as often as every 5 minutes if necessary? Its users would only lose data changed since the last backup. The sole expense would be that of a quarantined backup computer and the power to run it. That has to be cheaper than a bitcoin ransom.
I believe I'll have another drink, or maybe not
Guy Cox suggests that the inability to make a decision proves free will exists (Letters, 6 July). A deterministic decision-making process can find the weights of multiple options to be equal and so be unable to decide. It doesn't follow that because I can't decide whether to have an extra pint before I go home, therefore I must have free will.
Cash isn't the only driver for returning a wallet
It seems that lost wallets with more money inside are more likely to be returned than those with smaller sums (29 June, p 17). Someone who finds one will probably consider the amount of trouble they would have to go to in order to return it compared with the benefit to the person who lost it.
Personally, I would think twice about returning a wallet with only a few dollars in it. But if it had a credit card and driver's licence in it, that surely would be the real driver for returning it.
Lions in trees are more common than we think
You present a photograph of lions climbing trees in Lake Nakuru National Park in Kenya's Great Rift Valley and say that this is a relatively rare behaviour (6 July, p 26). I photographed lions doing this in Solio Ranch, Kenya, in 1995.
The editor writes:
This could be as a result of local pressures and limited to certain lion groups. A study in Tanzania's Lake Manyara National Park found that lions climbed trees to avoid buffalo and elephants, but this behaviour was observed less often in the Serengeti National Park, even though the same types of trees are there.
The metric system is not in fact a French plot
Allow me to express my support for Feedback's comments on the metric system (Feedback, 22 June). But though it was certainly developed in France, its roots lie with English bishop John Wilkins, who of measurement in 1668.
Please tell us the worst on methane emissions
Michael Le Page reports that climate models may have missed major effects from clouds (2 March, p 10). Two more effects, which James Lovelock described in , are the effects of methane emitted from melting tundra and from underwater methane hydrate. Then there are the fires in Arctic forests and peat.
I hope that someone will give us worst-case estimates for how high mean global temperatures could rise if those methane stores are substantially released, and for the lowest temperatures at which such mobilisation could be triggered.
Of course, there will be huge uncertainties in these numbers because, for example, estimates of the quantity of methane hydrate . But having worst-case estimates could provoke research aimed at reducing uncertainty.
Do we already know why cat owners are bolder?
I wonder why Ruth Searle writes of surprise that cat owners were found to be more adventurous and unconventional than dog people (6 July, p 43). Just last year, you reported that many cat owners are infected with Toxoplasma gondii, a parasite carried by cats that makes infected animals, including humans, more prone to risky behaviour (4 August 2018, p 17).
We haven't actually seen intelligent glass yet
Donna Lu reports that researchers have created a glass artificial intelligence (13 July, p 7). But their says only that they did computer simulations of what would happen to light inside such material.
They modified the distribution of areas with different indices of refraction in the simulation until they got the simulated material to behave in the way they wanted.
The editor writes:
The researchers respond that in the field of optics and AI, the computer model is considered to be an extremely high fidelity reproduction of the real thing. They do have plans to put the results into a physical object.
For the record 鈥� 3 August 2019
鈥� Cold facts: An Arctic fox travelled 3506 kilometres during a 76-day polar marathon (6 July, p 16).
鈥� We’re shaken: The epicentre of an earthquake is on Earth’s surface above its focus (13 July, p 7).