Editor's pick – Several approaches to rescuing the Arctic Ocean (3)
The melting of the Greenland ice sheet could be reduced by slowing the seaward movement of glaciers. Moulins, holes that meltwater flows down, reduce friction between the base of the ice and the bedrock.
If a moulin is filled to the top, water pressure at the glacier base can be roughly equal to the pressure of the overlying ice. This results in the glacier almost floating away on the water at its base.
Bulldozing dams across the meltwater streams to divert water around a moulin and so reduce the flow under the glacier could be a quick fix. Or we could use large solar reflective sheets, supported by balloons, to cover moulins and refreeze water. Solar-powered propellers could keep the reflective sheets in position.
Editor's pick – Several approaches to rescuing the Arctic Ocean (1)
Just how big a cynic does it make me that when I read Rowan Hooper's article on refreezing the Arctic, I couldn't shake the conviction that certain politicians who are supposedly climate change sceptics may have links to corporations that can't wait to get their snouts in the geoengineering trough? (31 August, p 38)
Editor's pick – Several approaches to rescuing the Arctic Ocean (2)
Assuming that the ice does mostly melt, as seems likely, the Arctic could be the place that comes to the planet’s rescue. This may have happened before. During the early Eocene Epoch, the atmospheric carbon dioxide concentration peaked at 鈥� at present, it is around (and rising).
The Arctic Ocean had only one narrow channel to the other oceans. It probably had fresh water floating over saltwater.
, freshwater ferns that fix nitrogen, grew here and , bringing carbon dioxide concentrations down to 650 ppm. Dead Azolla sank to the anoxic depths, where its carbon still lies locked.
As geoengineering projects go, closing off the Arctic Ocean is quite a modest proposal. Of course, we would have to wait for the Arctic to warm a little more and for a floating freshwater cap to form before a second Azolla event could really take off. Thereafter, the process would be self-sustaining, and self-limiting once the ice returns.
Money can't buy you happiness or contentment
Apparently, the search for happiness is now a well-funded industry (31 August, p 30). Surely this calls into question whether spending so much time, money and, quite possibly, anxiety in its pursuit is counter-productive.
Instead, wouldn't it be better to question what exactly happiness is? To me, it is experienced in response to a joyous event or achievement. It is fleeting, before a return to the baseline. Maintain this state for too long and it will lose its magic. More superlative events will be needed to maintain this level of happiness, inflating everyday irritations to trauma.
Surely the answer lies in contentment? A neutral level of default temperament offers a greater ability to enjoy genuine happiness at all levels, to keep minor annoyances in perspective and to promote greater strength in dealing with misfortune.
Maybe grandchildren, not children, make us happier
Alice Klein reports that having children makes us happier, but only when they leave home (24 August, p 12). This is consistent with a previous study (5 September 2015, p 40) showing that parents over 40 were happier than younger parents. I suggested (Letters, 26 September 2015) that it is grandchildren who make us happier. The latest study, concentrating on parents over 50, supports this, since children living at home are less likely to have their own children.
Please find a lower-impact kind of random curiosity
You suggest readers download a computer program to search for Mersenne primes in the background (10 August, p 38). Yet every week you report the looming peril of climate change and the need to change our behaviour to limit it.
Modern laptops and many desktop computers throttle back the processor speed and put their drives to sleep when idle. This significantly reduces power consumption. Installing software that keeps the processor loaded and that reads and writes data will prevent this – all to try to find mathematical objects for the sake of curiosity. How much extra carbon dioxide do you think would be released if every reader did as you suggest?
There are less energy-intensive ways to find rare things. You could catalogue birds, insects and plants for scientific surveys, for instance. There are also distributed software projects seeking potentially beneficial things, such as the effort to elucidate protein structures (8 November 2008, p 36).
Neanderthals' ears could indicate an aquatic past
Neanderthals' ears show signs of time in the water, as Ruby Prosser Scully reports (24 August, p 17). This seems to lend credence to the idea that humans led a semi-aquatic lifestyle, possibly before the split between Neanderthals and Homo sapiens.
Wading for fish and shellfish could have driven development of long hind limbs and an upright stance, with buoyancy giving support during the transition. These changes could have given us the posture required to carry a large, heavy head.
A seafood diet provides high-quality protein and lecithin for the development of a large brain. Add to this the characteristics we share with sea mammals: salt tears, a diving reflex and blubber.
I would love to see this possible evolutionary path explored more.
Why can't we use seawater to make hydrogen?
As Chris deSilva says, exporting hydrogen produced by electrolysis is like exporting water (Letters, 20 July). But why use fresh water? Pure water is essentially a non-conductor, while seawater conducts electricity, aiding electrolysis. It may also have useful by-products, such as industrially useful rare earth metals, cobalt and lithium. If some desalination is necessary, use the same photovoltaic or wind-generated electricity that would be used for the electrolysis.
Lord make me admit my ignorance, but not yet
According to Anna Ijjas, Saint Augustine is said to have quipped that prior to creating the universe, God was preparing hell for those who pry into mysteries (17 August, p 42). What he in fact is: “I answer the man who says, ‘What did God do before he made heaven and earth?’ I do not give the answer that someone is said to have given, evading by a joke the force of the objection: ‘He was preparing hell for those prying into such deep subjects’… I would rather respond ‘I do not know’, concerning what I do not know, rather than say something for which a man inquiring about such profound matters is laughed at, while the one giving false answer is praised.”
And the award for most complex object goes to…
Guy Cox discusses whether our brains are the most complex objects in the universe, as they are parts of bodies, which are parts of societies… This implies some complexity metric: perhaps the bytes needed to describe an object divided by its volume (Letters, 10 August). Otherwise, the universe must be the most complex object in the universe.
For the record – 21 September 2019
鈥� The photo illustrating our note about the kakapo population hitting 200 was of a different parrot (31 August, p 21).
鈥� We loathe vans (and other vehicles) spitting out nitrogen oxides (7 September, p 42).