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Solar warming
Letters– No quick carbon fix From John O’Hara While Richard Branson’s offer of $25 million for the first person to devise a way of scrubbing greenhouse gases out of the atmosphere is no doubt made with the best of intentions, it is misguided and more likely to be counterproductive to the cause (17 February, p 5). First, it is exceedingly unlikely that there is any “magic bullet” solution to atmospheric scrubbing. We must bear in mind that several gases are involved, and the scale of the atmosphere. Secondly, any research in this area will probably be specific to particular industrial processes. It will thus be conducted irrespective of whether or not there is a Branson prize. Thirdly, and more seriously, the existence of this prize may well reinforce the inertial mindset within the broad population: “OK, we’ve got a problem, but science will come to the rescue, it usually does, so we don’t really need to change our behaviour, business as usual, while awaiting the scientific ‘fix’.” Mount Waverley, Victoria, Australia From Charles Wartnaby Ian Jones of the Ocean Technology Group at the University of Sydney, Australia, has suggested expending energy to synthesise fertiliser and using it to grow plankton in the ocean to capture carbon dioxide. Meanwhile, your article on urine recycling explained that CO2 would be saved by separating urine from sewage to avoid the cost of removing nitrogen and phosphorus (23/30 December 2006, p 45). So why not combine these benefits and dump separated urine directly into sunny areas of open ocean? This notwithstanding the problem of hormones or their mimics in the urine, raised by Barbara Lai (27 January, p 21). Meanwhile, ever-tighter vehicle emissions regulations, 20 | NewScientist | 3 March 2007
focused on air quality rather than climate change, are leading engine makers to fit new diesel exhaust systems with selective catalytic reduction units in which nitrogen oxides are removed by reacting them with urea. Urea is generally made energyintensively from natural gas, through hydrogen and ammonia intermediates. As the new systems come on-stream, large quantities of urea will be required for the diesel vehicle fleet. Recycling urine to yield urea solution could produce a useful energy saving, though some have joked that truck drivers could top up their tanks directly. I eagerly await my cheque for $25 million. Cambridge, UK
The sweet smell of dad From Tom Batot Frazier Reading Mairi Macleod’s article about the effect that the presence of a girl’s biological father has on the age she reaches puberty, I am surprised that more thought has not been given to the importance of chemical communications (10 February, p 38). Something so fundamental to all life forms as pheromones should be expected to have a powerful influence on us too. Could it be that men’s pheromones have decreased because of the increase in bathing in the past 150 years or the more recent use of deodorants, which are known to be powerfully influential chemicals? Our pheromones presumably evolved because they served a
purpose. Have we disturbed a human communication medium that is critical to childhood development? Munich, Germany
Solar warming From Arthur Milsom You report the suggestion by Henrik Svensmark and others that changes in solar activity, which possibly result in changes in the level of cosmic radiation entering the atmosphere, may be partly to blame for global warming (10 February, p 9). It should be pointed out that solar activity shows a slight downward trend since the middle of the 20th century, as recorded by the international Wolf sunspot numbers. These cover the past 300 years and are the only reasonably reliable longterm measure. Solar activity varies in approximately 11-year cycles; we are currently at a minimum. The peak of the most recent cycle was only 60 per cent as high as that in the 1950s. It was not as high as some of the peaks in the 1700s, when global temperatures were significantly lower than at present. These observations seem to be at variance with Svensmark’s thesis. Alverstone, Isle of Wight, UK
Look again at trauma From Dee Blinka I was disappointed that in discussing post-traumatic stress disorder (PTSD) Laura Spinney dismissed eye movement desensitisation and reprocessing (EMDR) as if it was just slightly better than snake oil (3 February, p 40). There is an impressive body of robust research showing that this modern therapy for trauma is, in fact, effective. It is endorsed as such by many prestigious institutions worldwide, including the American Psychiatric Association in its practice guidelines for the treatment of
PTSD, which gives EMDR the same status as cognitive behavioural therapy as an effective treatment for the symptoms of both acute and chronic PTSD. The UK Department of Health and many other international health and governmental agencies have also endorsed EMDR. Documentation of the broad research base for this endorsement is readily available to any earnest reporter at the EMDR International Association website at www.emdria.org. Waco, Texas, US
Don’t bet on it From Bob Muirhead Stephen Oh claims that 70 per cent of 200 users of his Accuscore game predictor “said they were up ‘a little or a lot’ in their betting” (3 February, p 36). This statistic is virtually worthless. How were the 200 users chosen? Presumably they were
the respondents to a request sent to all users, in which case there is bias right away: only successful betters are likely to want to brag of their success. Losers will tend to ignore the survey. Even if the 200 betters were a representative sample of all users, there would still likely be positive bias in the results. Some, perhaps many, respondents will make a quick, intuitive assessment of their success without actually going through their records and doing the calculations. Memory is notoriously unreliable and biased to the positive when making intuitive assessments. www.newscientist.com
focused on air quality rather than climate change, are leading engine makers to fit new diesel exhaust systems with selective catalytic reduction units in which nitrogen oxides are removed by reacting them with urea. Urea is generally made energyintensively from natural gas, through hydrogen and ammonia intermediates. As the new systems come on-stream, large quantities of urea will be required for the diesel vehicle fleet. Recycling urine to yield urea solution could produce a useful energy saving, though some have joked that truck drivers could top up their tanks directly. I eagerly await my cheque for $25 million. Cambridge, UK
The sweet smell of dad From Tom Batot Frazier Reading Mairi Macleod’s article about the effect that the presence of a girl’s biological father has on the age she reaches puberty, I am surprised that more thought has not been given to the importance of chemical communications (10 February, p 38). Something so fundamental to all life forms as pheromones should be expected to have a powerful influence on us too. Could it be that men’s pheromones have decreased because of the increase in bathing in the past 150 years or the more recent use of deodorants, which are known to be powerfully influential chemicals? Our pheromones presumably evolved because they served a
purpose. Have we disturbed a human communication medium that is critical to childhood development? Munich, Germany
Solar warming From Arthur Milsom You report the suggestion by Henrik Svensmark and others that changes in solar activity, which possibly result in changes in the level of cosmic radiation entering the atmosphere, may be partly to blame for global warming (10 February, p 9). It should be pointed out that solar activity shows a slight downward trend since the middle of the 20th century, as recorded by the international Wolf sunspot numbers. These cover the past 300 years and are the only reasonably reliable longterm measure. Solar activity varies in approximately 11-year cycles; we are currently at a minimum. The peak of the most recent cycle was only 60 per cent as high as that in the 1950s. It was not as high as some of the peaks in the 1700s, when global temperatures were significantly lower than at present. These observations seem to be at variance with Svensmark’s thesis. Alverstone, Isle of Wight, UK
Look again at trauma From Dee Blinka I was disappointed that in discussing post-traumatic stress disorder (PTSD) Laura Spinney dismissed eye movement desensitisation and reprocessing (EMDR) as if it was just slightly better than snake oil (3 February, p 40). There is an impressive body of robust research showing that this modern therapy for trauma is, in fact, effective. It is endorsed as such by many prestigious institutions worldwide, including the American Psychiatric Association in its practice guidelines for the treatment of
PTSD, which gives EMDR the same status as cognitive behavioural therapy as an effective treatment for the symptoms of both acute and chronic PTSD. The UK Department of Health and many other international health and governmental agencies have also endorsed EMDR. Documentation of the broad research base for this endorsement is readily available to any earnest reporter at the EMDR International Association website at www.emdria.org. Waco, Texas, US
Don’t bet on it From Bob Muirhead Stephen Oh claims that 70 per cent of 200 users of his Accuscore game predictor “said they were up ‘a little or a lot’ in their betting” (3 February, p 36). This statistic is virtually worthless. How were the 200 users chosen? Presumably they were
the respondents to a request sent to all users, in which case there is bias right away: only successful betters are likely to want to brag of their success. Losers will tend to ignore the survey. Even if the 200 betters were a representative sample of all users, there would still likely be positive bias in the results. Some, perhaps many, respondents will make a quick, intuitive assessment of their success without actually going through their records and doing the calculations. Memory is notoriously unreliable and biased to the positive when making intuitive assessments. www.newscientist.com