Green eating
Bob Holmes assesses the environmental argument for giving up eating meat (17 July, p 28), tacitly accepting the broad scientific consensus that current animal-farming techniques have unsustainable environmental impacts. However, it is not just meat that is implicated in such damage, but all products we derive from farmed animals.
The Vegan Society has reviewed the evidence in its literature ().
Holmes suggests that radical transformation of the animal-farming industry might one day reduce the environmental damage it causes. That’s all well and good, but the fact is that the world’s animal-farming industry, as it is today, is one of the top three causes of all major environmental problems, from local water pollution to global climate change.
This implies that there is a strong environmental case for switching from meat to plant-based alternatives.
From Vicki Hird, Real Food Team, Friends of the Earth
With a growing global population to feed and livestock farming already eating the planet, extensive farming methods 鈥� where animals are raised in pasture with minimum inputs 鈥� are sometimes dismissed as a luxury we cannot afford. But our research shows we do not need to choose between vegetarianism and unsustainable factory farms: the world can produce enough food, including meat, for everyone without jeopardising its future.
Our modelling, as outlined in our report , shows that the world can provide 9 billion people (the projected population for 2050) with a healthy diet, including two to three portions of meat each week, using organic-based and free-range methods. It will require political will as well as technological change, but a fair and better diet is possible.
London, UK
From Geoff Russell
Holmes suggests we feed animals on waste. We can, but the issue is how many and how well. Australians in 2007 consumed about 1.8 million tonnes of cereals and yes, I’ll bet we threw out some mouldy bread. However, we didn’t waste anything like the 8.8 million tonnes of cereals our livestock consumed. Many of our livestock eat grass as well: in 2006, when there was less grass around, Australian livestock consumed about 10.1 million tonnes of cereals.
Holmes’s claim that “a little bit of animal protein can make a big difference to a marginal diet” is often repeated but is quite misleading, because marginal diets can be equally well improved with non-animal protein. This was put to the test in some extensive trials in Kenya. A paper by Monika Grillenberger and colleagues concluded that feeding Kenyan children more of what they normally ate 鈥� beans, corn and greens 鈥� had a similarly beneficial effect to adding extra meat or milk (, vol 133, p 3957S).
St Morris, South Australia
From Kath Clements
In Holmes’s article, it is suggested that keeping pigs is the solution to the current massive waste of food, and would provide a “net gain of calories and protein”. A better solution is to stop wasting so much food in the first place. In any case it is illegal, in the UK at least, to feed any waste food to pigs or any animal normally farmed. There are good reasons for this based on the UK’s experiences with foot and mouth and Creutzfeldt-Jakob disease. A pig is a sentient creature, not “your useful dustbin” as researcher Tara Garnett is quoted as saying. I don’t think local councils would take kindly to us keeping them in our backyards.
Sheffield, UK
From Graeme Hendry
Holmes offers up the disappearance of the leather industry as a downside of a vegetarian world. This ignores the tanning process’s contribution to pollution. According to the World Bank’s “the potential environmental impacts of tanning are significant”, with waste products containing chromium, sulphide, nitrogen and chloride produced in large quantities, to name a few.
Rainham, Kent, UK
Synthetic biology
Like Tom Wakeford and Jackie Haq (26 June, p 26), we were part of the group overseeing the preliminary dialogue between scientists and members of the public, discussing breakthroughs in synthetic biology with a view to gauging their response to the new technologies.
We consider that during the dialogue, several scientists made statements about synthetic biology that bore no relation to current knowledge, and did not mention the uncertainties involved. In particular, we felt that the principle of scientific uncertainty was not always fully conveyed, despite, in our opinion, the public being perfectly capable of understanding it.
We sense that core values in science risk being eroded, perhaps by the struggle for funds, the pressure for marketable results or by a lack of respect for public opinion. This is of particular concern considering the key role scientists play in communicating new and emerging technologies to the public.
Due to the multidisciplinary nature of synthetic biology, we need to be aware that there are competing scientific cultures and outlooks in this field. Of utmost importance is the protection of the “inconvenient uncertainties” in biological systems: our knowledge of how living organisms and biological systems function is full of gaps, and we must resist the convenience of treating an organism as a series of parts to be assembled. We must ensure that all hypotheses are tested against observation.
These are major challenges for the scientific community. To overcome them we need to ensure that uncertainties and gaps in knowledge are properly reflected in all scientific debates. The synthetic biology dialogue was to be a first step towards assessing the field and developing a process for public examination of proposed new technologies. The next steps will be crucial both for public trust and scientific debate.
World politics
Clive Hamilton’s article on the debate over geoengineering highlights a regrettable tendency for discussion of climate change to be polarised by political dogma (17 July, p 22).
Hamilton mentions as proponents of geoengineering right-wing think tanks opposed to fossil fuel cuts on political grounds. However, increasingly, reputable scientists are considering the effectiveness of geoengineering proposals and their side effects. He describes as ironic the fact that some of those now advocating geoengineering are “climate sceptics”. Yet they may not actually be sceptical about human-induced climate change, just unconvinced about the rationale for cutting fossil fuel usage. We agree there should be a public debate on geoengineering before considering any large-scale deployment, but that debate should be informed by objective analysis rather than the politically polarised, caricatured picture that Hamilton paints.
Playing with fire
The lack of evidence of humans controlling fire 2 million years ago need not be a stumbling block to the hypothesis that the discovery of cooking at that time caused humans to evolve so differently from other primates (17 July, p 12).
It is possible that we ate cooked food for a long time before we could make fire for ourselves. There have always been natural creators of fire, such as lightning, volcanism and bush fires. A precursor to controlling fire could be to notice that a dying fire relights when the wind blows. By seeing this, humans could learn to rekindle a fire and use it for cooking. Keeping the same fire lit for as long as possible might even explain decisions to localise hunting to the surrounding area, and thus settlements. Early humans would then have more time to discover edible plants.
Later on, a fire-keeper could have emerged who would carry a stick in embers to light a new fire, enabling migration. While using these natural methods, there would be ample time to discover how to make and control fire as we got smarter.
Largely quantum
Michael Brooks mentions the double-slit experiment, saying that as long as no one is watching, the photon exists in two places at once. When discussing Markus Arndt’s application, which showed that a carbon-70 molecule can also go through two slits at once, he states that: “though these ball-shaped molecules aren’t quite as substantial as cats, they can nonetheless be seen through a microscope” (26 June, p 34). How many cat flaps did Schr枚dinger have? If he wasn’t watching, which flap did the cat use?
Grow on, my sun
Stuart Clark suggests that, because the sun’s output is reducing, the sun is shrinking (12 June, p 30).
Conditions on the sun’s surface may not be allowing as much energy to escape as before, but there is no evidence to suggest that the sun is creating less energy below the surface. The sun may be retaining more of its energy and possibly getting hotter beneath the surface, meaning it might even be enlarging.
Medical brainwave
Helen Thomson describes how haphazard brainwaves may be behind some of the symptoms of schizophrenia (10 July, p 28). Temporal lobe epilepsy is spread by abnormal waves of neural excitation, and is often associated with disorders of memory and attention. Could this open up new treatments for the condition?
Healing affection
You report that people with schizophrenia might benefit from spraying the “cuddle chemical” oxytocin up their noses (17 July, p 10). What about a good old-fashioned cuddle? The production of synthetic oxytocin will probably be very profitable for some company or other, but who knows, there may be volunteers for the real thing.
For the record
鈥� We claimed there are monkeys in Madagascar (24 July, p 10). There are no native monkeys there, although there are plenty of prosimian primates.
鈥� The numbers of eggs displayed in the diagram accompanying our article on a vegetarian world were all too small by a factor of 1000 (17 July, p 28)