Water conflict
Fred Pearce rightly points out that what we call land-grabbing is often also water-grabbing, and calls for global estimates of the problem (2 March, p 28). Grabbing is not new, so calculations should look beyond the recent rush by investors for land and water in river basins, and should include historical data.
For example, the recent killing of more than 150 people in clashes over resources in Kenya’s Tana Delta are linked to dam construction and failed large-scale irrigation schemes in the 1980s and 1990s. This reduced the flooded area in the delta. Instead of 100,000 users fishing, cultivating and grazing 200,000 hectares, there are now 200,000 users trying to do the same on 100,000 hectares.
Water grabs are even more difficult to quantify because some investors hold off cultivating their land while they watch global markets to determine where the biggest profits can be made.
So yes, we need to do the calculations Pearce suggests, but include the past and the worst-case scenario, in which dormant plans are implemented. And we need to be aware of the suffering it has caused, still causes and will cause vulnerable people who are not to blame for climate change.
Dead or alive?
Sam Parnia talks about bringing people back after cardiac arrest 鈥� which he calls back from “death”, although he notes this is not the “social perception of death” as an irreversible state (9 March, p 32). That work is interesting and sounds medically valuable.
Then Parnia turns his attention to near-death experiences. There is much evidence that conscious experience is based on physical processes in the brain, that out-of-body experiences are hallucinations that can be induced with simple tricks or electrical probes, that people having such experiences cannot see anything that is not observable from the vantage point of their body, and that near-death experiences are simply hallucinations and after-the-fact confabulations.
Parnia says that such experiences cannot be hallucinations because “the brain doesn’t function after death”. Nobody claims it does. The brain functions immediately before and immediately after what he refers to as “death”, and during those periods it can and does hallucinate and confabulate.
Antioxidant angst
James Watson argues that antioxidant supplements might promote rather than deter cancer. He points to the suspected role of the body’s own antioxidants in allowing drug-resistant cancers to thrive via their ability to suppress oxidants unleashed by chemo- or radiotherapy. These oxidants usually trigger apoptosis 鈥� programmed cell death 鈥� in the cancer (16 March, p 28).
However, there is another possible mechanism to consider. He mentions the use of the diabetes drug Metformin for drug-resistant cancers. This is a known inhibitor of a cellular process called the mTOR signalling system. Inhibition of this can cause resistant cancer cells to die by unleashing another form of cell death.
Some of the antioxidants in fruits and vegetables are also inhibitors of mTOR and may have the same effect. So any anti-cancer benefits of these are probably happening in this way, rather than by a direct antioxidant effect.
Misery restored
In your Instant Expert guide to photosynthesis (2 February) you discuss tweaking photosynthesis to improve crop yields. I have no doubt that with enough research we will succeed.
However, to quote from Richard Dawkins’s book River Out Of Eden: “If there is ever a time of plenty, this very fact will automatically lead to an increase in population until the natural state of starvation and misery is restored.”
Twister logic
Mark Simpson and Ari Glezer’s proposal to extract energy using turbines powered by natural vortexes created by warm surfaces (9 March, p 23) begs a question: could enough vortex turbines extract enough energy from the rising air in Tornado Alley in the US to tame or at least lessen the annual destruction?
I can see one potential barrier. It would be impossible to build all the turbines needed (millions) in a single season. An inadequate number of turbines might risk attracting a natural tornado to a turbine, possibly wrecking it. Could the turbines even spawn tornadoes? If so, there would be accompanying lawsuits. This is America, after all.
Fluid situation
The claim that 184,000 deaths a year can be associated with sugary drinks is more sensationalism than science (23 March, p 5).
The study cited has not yet been peer-reviewed or published, and the report does not contain any evidence to show that consuming sugary soft drinks is the cause of chronic diseases.
Too tribal
Reports that Neanderthals might have become extinct because of their lack of social skills compared with Homo sapiens should not make us complacent (16 March, p 8). Our ability to maintain personal social groups of around 150 individuals and nation states of millions are impressive.
But if we see those beyond our groups as deserving death, we might not last much longer. We need to value and protect the lives of everyone on the planet. I write on a day when in UK tabloid newspaper The Sun, the chief concern about the new pope is that he is Argentinian 鈥� a nation the UK went to war with over the Falkland Islands.
No free pass
Following Alex Berezow and Hank Campbell’s article on the distortion of science by progressives (2 February, p 24), rebuttals from your readers appeared every week, starting two issues later and continuing for the next three issues 鈥� unprecedented, at least in the dozen or so years I have subscribed to 快猫短视频.
Clearly, Berezow and Campbell hit a nerve, and one that is worth repeating: “Conservatives who endorse unscientific ideas are blasted by the scientific community, yet progressives who do the same get a free pass. It is important the problem be recognised, and that free pass revoked.” Kudos to you for having the guts and intellectual honesty to publish the article.
Bee balanced
I am very pleased that a sound scientific risk approach has been taken by the European Union in its decision not to suspend use of neonicotinoid insecticides, as proposed last year (7 April 2012, p 18). There is still not enough evidence for a ban. Of course they could kill bees 鈥� they are insecticides. But it has not been proved that they do this, or if sublethal effects occur and damage bee colonies on an important scale.
Many other factors are likely to affect bee colonies 鈥� the varroa mite, the bee viruses the mite spreads, the pesticides used to kill the varroa, climate effects and flower supplies 鈥� and these must all be considered. We need a proper science-led assessment to help balance the risks and benefits for crop protection, pollination, ecosystem function and health.
Boom beater
The idea that a thin layer of plasma on aircraft wings can be used to reduce drag (9 March, p 48) took me back decades to when Concorde was losing overflying rights because of the sonic boom it created. Smoothing the flow of air around such jets would help diminish the boom 鈥� maybe plasma could be used.
Perhaps my dream might come true, and boomless supersonic aircraft will be commonplace.
Space sickness
Those planning to mine in space (2 March, p 8) need to consider the possibility that they will bring home a cargo of chemicals and life forms hitherto unknown on Earth. These may not be harmful to space miners covered in space suits, but contact and inhalation hazards may arise back on Earth.
Antibiotic hope
It is unsurprising that bacterial resistance, cost-effectiveness and patent restrictions are strangling the development of new conventional antibiotics (16 March, p 6). What needs to be heard above the groans is that several different approaches are being investigated, often with little funding.
Bactericidal bacteriophages, RNA interference and the small peptides of the innate immune system are just three avenues of exploration largely written off during the antibiotic golden age, any one of which might, in time, lead to a second golden age.
A solution to some of the problems of antibiotic misuse would be to ensure that they are only available as single-dose, slow-release formulations delivered by injection 鈥� like the kind my dog gets from the vet.
This would resolve the issue of people not taking the full course. An injection would discourage casual use and deter demands for antibiotics for minor illnesses.
Stocksfield, Northumberland, UK
Friendly wolves
As regards how wolves became domesticated, there is another probable starting point that complements Brian Hare’s explanation (2 March, p 30). Hunters come across an abandoned litter. If they are close enough to base and on the homeward leg, they take the young home for the kids.
Dogs have effectively discovered a new niche. They fill it via rapid evolution, chiefly by neoteny 鈥� retaining juvenile characteristics that are useful to humans, such as friendliness, trust and playfulness.