Canine free-for-all is already here
You report that there are around a billion dogs in the world, with up to 85 per cent free to interact with the environment to some degree as feral or street dogs (24 July, p 43).
While your article imagines how dogs might fare in a future without us, a world without responsible human ownership of canines is in effect already here. Biodiversity, human health and the environment are severely affected by free-roaming dogs on all continents.
Humans and domestic animals are infected by rabies and other diseases that dogs can carry. From the predation of endangered birds in New Zealand to the demise of endemic lizards in central Chile, dogs affect many wild species too. The ecological paw print of our dogs has been underestimated.
Probably best if we don't spread across the galaxy (1)
What horrifying thoughts from geneticist Chris Mason, with his idea of spreading humans across the galaxy (17 July, p 44). We may be the most intellectual creatures on this planet, but are hardly a role model.
We kill our fellow humans in wars and our self-centred attitudes have eliminated many other species. Positive human traits are countered by the infiltration of greed and crime throughout society. We are already well on the way to creating a planet that is largely unfit for us to live on. Should we really seek to transfer these attitudes more widely?
Probably best if we don't spread across the galaxy (2)
Mason describes ambitious plans to ensure the long-term survival of humans. But to whom (or to what) does it matter if we become extinct? The very nature of the event means there will be nobody around to care. Indeed, I suspect that the other species on Earth would be glad to see the back of us.
The hard problem: why pavements are an issue (1)
Further to your article on the problems with pavements, years ago I learned that a long day of off-track walking was less tough on my feet than a few kilometres on a smooth path or vehicle track (10 July, p 46).
On uneven ground, every footfall is slightly different, requiring different muscles to balance and stride, so the loads and wear and tear are dispersed around the anatomy. However, on a pavement, every footfall and stride is identical, so wear and tear is focused on the same body parts.
Nearly 50 years later, my now arthritic toes are still happier off-track than on a pavement. I doubt if the proposed changes to the hardness of pavements will make much difference to this.
The hard problem: why pavements are an issue (2)
While the hardness of the concrete in sidewalk pavement is certainly an issue, it does have an advantage over asphalt-based alternatives: its much lighter colour reflects sunlight better and so stays cooler than darker materials, a benefit my dogs appreciate during walks.
Getting to the bottom of race-based medical issues
You report that race-based adjustments to diagnostic criteria reflect bad science and should be abolished (17 July, p 16). Fair enough. But we also often read that this or that medical procedure hasn’t been sufficiently validated because the clinical trials involved a limited cohort, for example mostly white people. We also sometimes read that a certain sector of the population is more susceptible than the rest of us to a particular ailment.
Are there differences or not? If there are, and “race” is the wrong distinction, we need to know what the right one is.
On the divisive issue of climate geoengineering (1)
John Koster says the time is right to try a massive and untested interference with marine ecosystems by seeding waters with iron to encourage plankton growth to capture carbon (Letters, 17 and 24 July). Yet such geoengineering risks perpetuating fossil-fuelled lifestyles.
Koster proposes that this takes place in the Southern Ocean. However, some of us do live in the southern hemisphere. What’s more, the Southern Ocean is the summer feeding ground for many whale species, whose populations are just beginning to recover. As a (former) marine biologist, I have to rate this as a truly horrible idea. We solve the climate crisis by not using fossil fuels, period.
On the divisive issue of climate geoengineering (2)
Paul Whiteley says seeding the ocean with iron will simply allow fossil fuel companies to keep their business models and politicians to avoid decisions. I’m not really in favour of such seeding, but even if we do drastically reduce our use of fossil fuels, we will still have a problem of too much carbon dioxide in the air, for a long time. We should find ways to reduce it.
Meth-addicted fish may not be at a disadvantage
You report that fish addicted to methamphetamines that end up in Czech rivers may have a reduced survival rate. It may not be so (17 July, p 20).
If both predators and prey are equally debilitated, then they will all still be on the same footing and the pollution may not make any difference. Surely, the first species to evolve tolerance to the drugs in the environment will be the winner 鈥� until the water gets cleaned up.
There is good and bad in all chemicals
Your article on chemical pollution made some good points, but there is often confusion about what a “chemical” actually is (24 July, p 36).
All materials are chemicals as there is no physical thing that is not made of chemicals. The idea of synthetic and natural chemicals is an artificial construct and often just wrong. Many substances labelled as synthetic pollutants are made in biological or natural processes in small amounts.
In addition, all chemicals are both dangerous and safe. It is how they are used that determines which predominates. At one extreme, you can drown in any liquid and all heavy objects are made of chemicals that can kill you if they fall on you. At the other end of the spectrum, even the most deadly chemicals can be made, handled, used and destroyed safely using appropriate methods.
It isn’t the chemicals themselves that are unsafe, it is the way that we decide to use and handle them that decides the helpful or harmful impact.