Editor's pick: Less a snowball, more of a slushball
Richard Webb describes the most extreme version of a “snowball Earth” event, as proposed by Joseph Kirschvink (18 July, p 28). Others have suggested milder “slushball Earth” events. Since life apparently bounced back quickly after each event, it must have found some refugia.
Research by , indicates that simple photosynthetic algae could have survived in a narrow body of water with characteristics similar to today’s Red Sea. The “hard snowball” interpretation 鈥� with equatorial temperatures of -50 掳C lasting tens of millions of years 鈥� would rule that out. So where did life hide out? Hibernation fails on time scales beyond millennia. Crater lakes may be warm, but no single volcano survives that long. Very salty lakes might remain liquid but will kill everything except extremophiles. Even organisms living at sea floor hot vents need oxygen, dissolved at the liquid surface. Yet we exist.
I see three possible answers; divine intervention (Norse gods battling the Ice Giants), a Doctor Who (operation Noah’s Tardis?) or… maybe science simply needs to look harder for evidence of milder “slushball Earth” events.
Ume氓, Sweden
Is burning biomass such a good idea?
Fred Pearce describes the White Rose power station at Drax in Yorkshire as the “world’s first power plant with negative emissions” (8 August, p 8). The Drax company is a master of political spin. In the last few months, it has managed to portray what would be the UK’s first new coal power station since the 1970s as a climate solution that reduces carbon dioxide in the atmosphere. It positions the burning of millions of tonnes of wood pellets as “low carbon” despite overwhelming evidence that many of those pellets are sourced from clearing some of the world’s most biodiverse subtropical forests.
To comply with UK planning policy and gain a 拢500 million (or potentially even 拢950 million) capital grant, White Rose must be built with the infrastructure for carbon capture and storage 鈥� but these guidelines don’t require much, if any, carbon to be captured once the plant is operated. The oxy-fuel technology proposed is much cheaper and more energy-efficient to operate without CCS than with it.
for the power station states that at least 85 per cent of the fuel will be coal, not biomass. All this is happening while UK support for wind and solar power as well as home efficiency is being slashed.
Edinburgh, UK
Is burning biomass such a good idea?
Our forests are a vital carbon sink storing more than 10 per cent of US emissions annually. Instead of valuing our forests for this and all of the other important services they provide, such as clean drinking water, wildlife habitat, protection from storm surges and flooding, and as a place for recreation, big utilities like Drax are pushing to chop them down and burn them for electricity, then call it great for the climate.
Asheville, North Carolina, US
<b>First class post</b>
Reading about confirmation bias, fixation error, primal freeze and outcome bias
MP he’s interested in why things fall apart (15 August, p 28).
Renewable energy is not taking over
Your interview with Malte Jansen of the avoided important issues (25 July, p 17). Jansen says Germany is “doing a fairly good job of getting to the target of 80 per cent renewable electricity by 2050”, but the use of fossil fuels to generate electricity . Decreased nuclear power production is reflected by an overall decline in electricity generation and increased electricity imports.
Rosdorf, Germany
What will recharge the world?
When I saw your headline about “the battery that will recharge the world” I hoped for news of a revolutionary battery technology (25 July, p 20).
If we are to use batteries to support a power generation system based mainly on solar and wind renewable energy, then the cost of battery storage will probably need to come down to less than $10 per kilowatt-hour 鈥� 100 times less than current cost.
In December 2010, there was a massive fall in wind power across Europe: output was just a few per cent of normal for a couple of weeks. Importantly this was also at a time when demand was near maximum and solar generation near minimum. To cover the UK shortfall alone in such a scenario would require more than 500 times the amount of batteries produced globally, but only once every few years.
Cheltenham, Gloucestershire, UK
Whalers and killer whales teamed up
Your report on two dolphin species banding together is intriguing to say the least (25 July, p 6). It brings to mind an alliance that existed between two species many years ago on the south-east coast of Australia.
Back when whaling was a primitive and dangerous artisanal enterprise, for the whalers to slaughter. All the orcas expected in return were the tongues from the killed whales.
This cooperation only existed between a particular pod of orcas and a particular human family. Rival whaling families tried to muscle in on the arrangement but without success.
Highett, Victoria, Australia
Cod's comeback isn't nearly enough
It was welcome news to hear that cod is making a comeback in the North Sea and stocks on the northern Grand Banks are also picking up (11 July, p 6). While we should acknowledge the good work politicians have done so far, I’m afraid this is only the tip of the iceberg if we want healthy oceans.
Around 40 years ago, near Iceland and in the White and Barents seas, we were using nylon trawls that, if hopelessly snagged, were abandoned there. They were very expensive, so we didn’t ditch them lightly. Now millions of tonnes of plastics and other garbage are dumped into the world’s oceans. And is the public aware that by-catch 鈥� unwanted marine life fetched up along with the saleable fish 鈥� includes dolphins, seals and turtles? Every politician on the planet needs to consider the health of the world’s oceans. They have to live on the same planet as us mortals.
Bridge, Kent, UK
The benefits of 'born this way'
Although I regard myself to be a gay man, I do find some women attractive. And, as Lisa Diamond suggests is often the case (25 July, p 18), the types of women and men to whom I am drawn have changed (a little) over my 68 years. You might call this “fluidity”.
I take issue, however, with the argument that this means we should ditch the “born this way” line. My father has reluctantly come to accept that theory. He says, however, that if I cannot be heterosexual, I should be celibate. If people like him are told that my sexuality is “fluid”, then I fear they would see it as proving that I could become heterosexual if I only tried hard enough.
“Born this way” may be simplistic, but I can see nuances in the “fluidity” argument being lost in societies that are determined to prove that homosexuals can be “converted”.
Name and address supplied
Responsibility and consciousness
David Amodio discusses how unconscious bias can determine our actions in some situations (18 July, p 26). But I believe that every conscious thought is supported by hundreds or thousands of subconscious systems. If I type “insulation” when I meant to type “insolation”, I think the word “no” and correct it: but what neural structure triggered the word “no”? What structure beneath that knows my text is related to solar radiation and did a check in that context?
It is silly to speak about my subconscious as if my conscious mind is independent of it. I don’t believe in conscious decisions; I believe that what we call a conscious decision is just an awareness that our myriad subconscious systems have collectively resolved a course of action or state of belief.
That does leave the possibility that one subsystem might hijack the whole and execute an action, such as shooting a child, that the collective of systems would reject if given time to reach a consensus. But the subsystem is not some alien: if it can seize control of a person then it is that person.
San Antonio, Texas, US
Doubts on E-cigs are not just puritan
As a doctor, I have spent time helping people to stop smoking, so I am delighted that Mike Taylor has been able to cut down with the aid of an e-cigarette (Letters, 8 August). But I disagree with his point that it is self-righteousness or puritanism that prevents medicine embracing the e-cig.
First, governments refuse to regulate the content of e-cigs, so we have no idea what they contain and in what quantities. Second, it takes a long time to carry out proper investigations into the health effects. Without that evidence, a doctor cannot advise their patient to use one 鈥� or not to.
Lancaster, UK
Doubts on E-cigs are not just puritan
鈥� Since we received this, Public Health England has concluded that e-cigarettes are less harmful than cigarettes and help most smokers to quit (). But concerns about e-cigs reducing the stigma of smoking may remain (1 November 2014, p 35).
Tell me lies, tell me sweet little lies
Bruno Verschuere might consider whether the reason young adults lie more than other age groups (1 August, p 23) is because they are those most likely to be seeking sexual partners.
West Launceston, Tasmania, Australia
<b>For the record</b>
鈥� All in a haze? We meant to say that the sun breaks down methane in Pluto’s atmosphere into fragments that then form hydrocarbon haze (1 August, p 5).