Editor's pick: Sup with him with a long spoon
It is always wise to be wary of the company one keeps. Have Veerabhadran Ramanathan, Partha Dasgupta and Peter Raven forgotten this wisdom when they back the pope’s call to action on climate change? “We are fortunate to have a global moral leader in Pope Francis”, they write (27 June, p 24). Science has been bitten by ill-considered company before and should be wary of being so again.
In the early stages of the public debate over climate change, scientists unreservedly accepted the support of green groups. But the findings and legitimate warnings of climate scientists have been tarred by the outlandish claims of extreme greens whose concern for the planet is often part of a wider political agenda. Climate change deniers regularly discredit scientists through association with the extreme fringe of the environmental movement.
The Pope leads one of the most anti-science organisations in the world. It has denied everything from the sun’s position at the centre of the Solar System to the effectiveness of condoms in stopping the transmission of HIV.
By all means, let the Pope rouse his flock to combat climate change 鈥� his massive influence could do some good. 快猫短视频s, however, should maintain a wary distance and keep their credibility intact.
Kenmore, Queensland, Australia
Crash courses in economics
“At what point does one stop trying to be diplomatic and adopt a rebellious stance?” asks David Sloan Wilson in your article on how biology could make economics more scientific (25 July, p 38). I suggest that no rebellion is necessary. Wilson and others have the intellectual credentials to start an independent study group with its own publications to develop their own independent “species” of economic science 鈥� one that actually works.
Eventually, any realistically predictive science will make mainstream economics irrelevant. I’d say that process has already begun: recent financial disasters have dealt a blow to the credibility of economists’ non-predictive magical thinking.
Wilson and his colleagues should found a discipline on the principle that models must exhibit predictive and explanatory power, and must discriminate between outcomes distinctly enough to be capable of being proven wrong.
San Antonio, Texas, US
Crash courses in economics
During my 50-year stint as an agricultural scientist I have had many interactions with economists. One of the things I learned very early on was that they use a different form of mathematics to everyone else. The second thing I learned was that it is forbidden to use a mathematical form in economics unless it has already been referenced in economic literature.
I was once charged with calculating the economic benefit of a technical change. I produced a model that assumed a minimum price below which the commodity wouldn’t be produced 鈥� if it costs $10 to produce something, you don’t do it if the market price is $9. This is obvious. It was met with immense resistance because the only supply curves referenced in the economic literature didn’t do that.
In the end, I prevailed and after much trial and tribulation with reviewers and editors, a paper was published that related to a single commodity 鈥� beans (). I’m sorry to say that the analysis didn’t go much further. The extension to multiple commodities was too much for the economic public.
Dolgellau, Gwynedd, UK
Crash courses in economics
Almost all economic forecasting exercises provide imprecise answers, but that shouldn’t detract from their usefulness.
We need to accept that the role of forecasts is simply to help us reduce uncertainty over possible future outcomes. This, inevitably, moves us into the realm of probabilities, rather than certainties. What is critical, and rarely done effectively, is for forecasts to be regularly reviewed to evaluate what worked and what didn’t. Learning from that analysis helps produce more reliable forecasts next time.
The same approach could be applied to astrology, but I doubt it would make any difference to the reliability of those projections.
London, UK
Crash courses in economics
The economy, like the weather, is a complex system with many feedback loops and chaotic characteristics. At some times it may be predictable, at others it may be possible to assign probabilities to outcomes, and at yet other times no prediction can be made at all.
But if the economy cannot be predicted reliably, then neither can the effect of any action taken to alter it. Who would choose a chancellor or Bank of England governor who admitted that the results of their decisions were unpredictable? Instead we all prefer to believe that in the darkness any candle is valuable, however dim. A dim candle, however, makes you think you see more than you really can. This causes accidents.
London, UK
<b>First class post</b>
The way a person became gay is irrelevant to entitlement to equal rights
Theo Koopman dives into about Lisa Diamond’s views on sexuality (1 August, p 24)
Make carbon levies fund research
Michael Le Page’s report of the resurgence of Old King Coal is a fitting prelude to the UN climate conference in Paris in December (18 July, p 10). And it is no surprise that policy-makers continue to think about the prospects of a carbon tax. But we should beware of calling it a “tax”. That word normally describes any sort of revenue that each state is free to spend as it thinks fit.
Whatever words are used to describe the variety of national or international charges for the use of fossil fuels, these should be accompanied by a strict condition that the resulting revenues may only be used to finance national and international programmes of research and development to achieve environmental targets.
Sunbury-on-Thames, Surrey, UK
Sink or swim to the Americas
You say it is unclear how or when genetic similarities arose between Native Americans in the Amazon and indigenous populations in the western Pacific and beyond (25 July, p 5). Perhaps we need look no further than the end of the last ice age, when sea level rose by in excess of 100 metres in little more than 2000 years.
This rise would have turned low-lying islands into submarine mountains, leaving the islands’ inhabitants with no alternative but to cast their fate to the ocean currents, which may have delivered some of them to the west coast of South America.
Whitwell, Isle of Wight, UK
People who make a climate difference
I was rather disappointed at Robert Gifford’s throwaway line near the end of his article on the psychological reasons we fail to act on climate change (11 July, p 28). He described people who choose not to have any children as being “honeybees 鈥� who engage in climate-positive behaviour for non-climate reasons”.
Statisticians at Oregon State University that, in the US, the carbon legacy and greenhouse gas impact of an extra child is almost 20 times more important than some of the other environmentally sensitive practices people might employ for their entire lives 鈥� things like using energy-efficient appliances, recycling or driving a high-mileage car.
This seems to suggest that these people are the ones contributing the most to combating climate change regardless of the author’s perception of their motives.
Pontardawe, West Glamorgan, UK
Could we redefine the second to fit?
In your look at our problems with recording the passing of time, your graph of clock time diverging from International Atomic Time makes me think that a partial solution would be to redefine the caesium-133 second that is used to measure atomic time (27 June, p 32). If it were larger by 185 cycles than the defined 9,162,631,770 鈥� one part in just less than 50 million 鈥� clock time would have tracked atomic time to within a few seconds over the past 55 years.
Although the discrepancies are not totally regular, the variables seem to be well enough pinned down to project forward hundreds of years. In fact the trends already apparent from 1960 to 1967 or 1972 would have provided a basis for adoption. The problem could then have been put on the back burner for hundreds of years.
Over, Cambridgeshire, UK
Space elevators are still science fiction
Jeff Hecht says we need to look seriously at space elevators and alternative propulsion for getting into space (18 July, p 24). Looking seriously won’t make them any more feasible.
A space elevator needs a cord that can support thousands of kilometres of its own weight. Even carbon nanotubes aren’t good enough. Alternative propulsion systems are great, once you are in space. But to blast off and get into orbit, you need to impart a speed of , in a few minutes.
Rocket engines using chemical fuels need much more fuel than the weight of the payload. The next option is nuclear fuel, which I wouldn’t recommend.
Les Essarts-le-Roi, France
Panthalassa ocean wasn't so empty
In his time traveller’s guide to Earth, imagining 250 million years ago, Joshua Howego wrote: “From the other side of the planet all you see is an unbroken expanse of ocean, Panthalassa” (18 July, p 28). Although Panthalassa is generally illustrated as an uninterrupted vast blue ocean, this is because of a lack of data.
Recent research has shown that volcanic arcs and small continents were present and would have interrupted the unbroken expanse. These have ended up in north-eastern Asia and western North America, where their remains are outcropping today. Subducted fragments of them are detected in the mantle beneath the Pacific. There is more detail in a 2012 paper I co-authored in Nature Geoscience ().
Ruislip, Middlesex, UK
<b>For the record</b>
鈥� The A2 Milk Company has asked us to clarify that it doesn’t promote A2 milk as dealing with non-communicable diseases (25 July, p 33). The company states that A2 Milk “is marketed for the benefit of people who may experience digestive discomfort with milk”.
鈥� It was X-rays that were an increasingly popular treatment for cancer, eczema and even hair removal in the 1930s; and Aloe vera was used to soothe skin damaged by overexposure to them (18 July, p 40).