On the battle against obesity related illness
I was interested to read about a new class of drugs to promote weight loss in “Obesity blockers” (7 May, p 46).
Although BMI and categories such as overweight and obese are widely used as a medical standard these days, it is worth considering that they are based on statistically grouping the population rather than on health markers. Even doctors are aware that they don’t really work for many people of colour.
Prescribing new drugs based on pretty arbitrary categories is perhaps not the best medical intervention. A simplistic view risks harming people.
Rather than uncritically pursuing weight loss as the ultimate health goal, we should be working towards a more individualised approach to health that considers weight as one of many factors and works to find better tools than BMI categories.
Totally wrong to view dogs as an invasive species
You report how a billion dogs, including our pets, are laying waste to wildlife (30 April, p 42). The article, and the issue’s cover, asks whether pet dogs are an invasive species, and then proceeds to answer with “such is their impact that some ecologists call them an invasive alien species”.
Let me suggest that, while pet dogs have a significant negative effect on wildlife and the environment, as documented in the article, viewing them as an “invasive species”, much less “alien”, borders on being wrong-headed and counterproductive.
It is equally accurate, perhaps more so, to portray modern dogs as a successful evolutionary adaptation in response to the invasion of their habitat by our own species.
We have already well and truly messed up the sea
We aren’t “at risk of repeating the mistakes” of our exploitation of land when it comes to the oceans, we have already done so on a grand scale (Leader, 23 April). The near obliteration of marine megafauna has had a terrible effect on the fecundity of the ocean environment and its natural long-term carbon capture and storage functions.
At the same time, smaller marine animals have been almost fished out. There are probably now orders of magnitude fewer fish than 500 years ago, if we are to believe the historical accounts describing the bounty around our shores and in deeper waters.
We simply don’t have enough information about how much we have degraded the seabed through industrial dragnet trawling, but it seems likely to have been catastrophic to large areas.
Of course, all of these things have synergised to make the consequences of each worse than if the others hadn’t happened.
Longer lifespans might not lead to happiness (1)
One aspect of longer lifespans that I haven’t seen mentioned is the psychological state of the elderly (30 April, p 38).
Many years ago, I observed that older people worried excessively. Now, in my late 70s, I find myself doing the same. The other thing is that as most of us go through life, we experience some trauma 鈥� the death of a loved one or a painful relationship being the most common, but not the only ones.
If we do extend human lifespan, as suggested, without addressing these problems, the world could be inhabited by physically active double centenarians who are totally neurotic.
Longer lifespans might not lead to happiness (2)
Everyone seems to think I am younger than I am. People are surprised when I say I will be 86 in July. This might be due to being a club cyclist since I was 14. But I suspect genetics may be at work.
My mother lived to 101 and a half. My mother’s eldest brother died at 103, one sister at 99, two at 97, one brother at 94 and one at 95. The remaining sister is now 97.
The real reasons why nuclear is a non-starter
I agree that nuclear power has waste problems and these should definitely give us pause for thought about building new reactors (Letters, 30 April). It is, however, safer than most technologies, given that the small number of accidents have killed relatively few people, with nothing like the mortality rate resulting from burning fossil fuels. I think that uranium, while technically a limited resource, is sufficiently abundant to be considered sustainable.
For me, the biggest argument against nuclear as an answer to the energy crisis is related to the long implementation time and the carbon costs of construction. In fact, the massive amount of concrete and other energy-hungry resources needed to build a fleet of reactors might make the climate impacts significantly worse over the next few decades.
Zero-covid strategy won't work for all countries (1)
Michael Marshall advocates that more countries should have followed the zero-covid playbook, as this led to lower death rates and better economic growth in the countries where it was adopted (2 April, p 27).
This may work in places where public health measures 鈥� social distancing, mask wearing, effective tracing, quarantine and vaccination 鈥� can be easily implemented and enforced. It becomes considerably more difficult where health regulation is controlled at the level of individual states in a country, which is the case for Australia.
Here, differences in public health requirements between states and the federal government caused confusion and restricted movement between states.
Zero-covid strategy won't work for all countries (2)
The UK started quarantining far too late as part of its covid-19 strategy. This was, however, inevitable given that the original virus was already in the UK long before anyone knew that it was spreading person to person. The real mistake was seeding nursing homes with untested people discharged from hospital.
Neanderthal genes, no interbreeding required?
Jake Buehler describes growing evidence for horizontal transfer of genes between some species via common parasites (30 April, p 10). Could this also explain genetic transfers between hominins inhabiting the same environment, like Neanderthals and modern humans?