The usual rules of sexual attraction go out of the window when men are stressed, say psychologists

Men are drawn to a wider range women when they are feeling stressed out, according to research into the psychology of sexual attraction.

People are usually attracted to partners with similar facial features to their own, but after a brief but stressful experience, men's preferences changed to include a wider variety of women, the study found.

Relaxed men who took part in the study rated women on average 14% less appealing if they looked very different from themselves compared with women who looked similar. But a group of stressed men found dissimilar women 9% more attractive.

Johanna Lass-Hennemann, who led the study at the University of Trier in Germany, said the findings echo research suggesting that animals lose their normal mating preferences when they are under stress.

"Men have a tendency to approach dissimilar mates and to rate these to be more pleasant when they are acutely stressed," Lass-Hennemann said. "[But] we are not sure how this might reflect in true mating decisions."

Scientists suspect the appeal of similar-looking partners may be linked to our tendency to have more trust in a familiar face, a factor that is important for long-term relationships. Under stress, however, the importance of pairing up with someone similar-looking seems to vanish.

Lass-Hennemann speculates that stress might increase men's tendency to "outbreed", or reproduce with more genetically dissimilar women, with the potential benefit that any children born from the relationship might be better equipped to cope with a stressful environment.

"We think that chronically stressful environments should increase outbreeding, because inbreeding may lead to offspring that are not genetically diverse enough to deal with the varying circumstances that a risky and stressful environment imposes on them," she said.

In the study, 50 healthy heterosexual male students were divided into two groups. Those in the first group were asked to plunge one arm into a bucket of icy water for three minutes before taking part in the test. Those in the second group were asked to do the same, but with water heated to body temperature.

Measurements of the volunteers' heart rates and levels of the stress hormone cortisol indicated that the men in the first group were significantly more stressed before the test began than those in the second.

In the test itself, the men were shown a series of images on a computer screen. Some were of household objects, but others were of naked women. Some of the women's faces had been digitally altered to resemble either the person being tested or another man in the group.

Throughout the test, the scientists played occasional bursts of noise to startle the men and recorded their reactions. Previous research suggests people startle less when they are looking at something they find attractive. The men were also asked to rate the images by how appealing and arousing they were.

While men in the control group performed as expected and were more attracted to women who looked like them, the stressed men consistently rated the unfamiliar women as more appealing. Their startle reactions confirmed their preferences.

The research is published in Proceedings of the Royal Society B.

Lass-Hennemann said it is highly unlikely that the acute stresses of everyday life can switch someone's tastes when it comes to choosing a partner, but long-term stress might shift male preferences towards women who are more dissimilar.

• Reproduction
• Psychology
• Biology
• Relationships
• Genetics

Ancient DNA has been extracted from the fossilised eggshells of birds for the first time, and will eventually yield clues about their physiology, diet and how they went extinct

Scientists have collected DNA from the fossilised eggshells of birds that died hundreds and in some cases thousands of years ago.

The oldest eggshell to yield DNA came from an Australian emu that died around 19,000 years ago. It is the first time that scientists have succeeded in extracting ancient DNA from the fossilised eggshells of a bird.

Genetic material from the Madagascan elephant bird, the heaviest bird that ever lived, was also recovered, along with DNA from Australian owls, New Zealand ducks and flightless moas.

Elephant birds were native to Madagascar but had gone extinct by the 17th century. The ostrich-like creatures grew to around 3 metres tall and weighed up to half a tonne. Their eggs were bigger than footballs.

Eggshells from two other extinct species, the little bush moa and the heavy footed moa, both from New Zealand's north island, were estimated to be more than 3,000 years old. Attempts to collect DNA from a 50,000-year-old flightless Australian bird from the genus Genyornis failed because the DNA had degraded too much.

The ancient DNA has yet to be sequenced, but researchers will soon be looking to draw up genetic profiles of long-lost birds by extracting genetic material from eggshells held in museums and excavated at archaeological and fossil sites.

Previously, they had little hope of reading DNA from species that lived in warm climates because the genetic material breaks down so quickly.

By sequencing the genomes of ancient birds, scientists hope to build up a better picture of their physiology and how they dispersed and split into different species. It may even be possible to surmise their diets from genes encoding the enzymes for digesting particular types of food.

Charlotte Oskam, who led the study at Murdoch University in Perth, Western Australia, is now analysing a large collection of eggshells from ancient sites in New Zealand and hopes that DNA profiles of the birds will help explain how the arrival of humans brought about the extinction of the giant moa around 500 years ago.

The researchers used a technique called confocal microscopy to see exactly where the DNA is located inside the egg shells of two of the extinct birds, the New Zealand giant moa and the Madagascan elephant bird.

From this they were able to say that the DNA almost certainly comes from the mother hen rather than the embryo growing inside the egg. When the egg moves away from the ovary, cells from the mother get mixed up in the calcium carbonate shell as it thickens.

The research, reported in Proceedings of the Royal Society B, does not mean scientists will soon be able to resurrect long-extinct birds. Although the DNA can be sequenced, scientists would need to know how to repackage it into chromosomes, the giant molecules that carry genes.

The same problem makes it unlikely that scientists will bring woolly mammoths back to life, even though their DNA has been sequenced from well-preserved specimens recovered from the Siberian permafrost.

"As with all ancient DNA, the DNA we isolated from eggshell is very fragmented," said Oskam. It will be possible to sequence extinct genomes from fossil eggshell, he said, "but it is a huge leap to imagine we can clone an extinct species."

• Fossils
• Genetics
• Evolution
• Biochemistry and molecular biology
• Zoology
• New Zealand
• Madagascar
• Australia

I agree with George Monbiot (Comment, 9 March) about the problems of communicating science, but it is a pity he did not mention the large amount of outreach work being done by scientists these days to address the very issues he raises, much of it in collaboration with Café Scientifique, a network of voluntary local initiatives in towns up and down the UK, and, indeed, the world. There is a Hippocratic oath for scientists, although it is not yet compulsory. It is called the Pugwash Pledge, and can be found at (www.spusa.org/pledge).

"I promise to work for a better world, where science and technology are used in socially responsible ways. I will not use my education for any purpose intended to harm human beings or the environment. Throughout my career, I will consider the ethical implications of my work before I take action. While the demands placed upon me may be great, I sign this declaration because I recognise that individual responsibility is the first step on the path to peace."

He might also be pleased to hear that very few of us wear beards these days.

Jim Grozier

Organiser, Brighton Café Scientifique

• What Peter Preston (Wanted: an eco prophet, 8 March) appears to omit is the emergence of eco-crankism – the proliferation of eco-friendly initiatives by a new class of do-gooder apparatchiks advising backyard gardeners to grow £1 carrots, use fashion-styled cotton carrier bags, cycle in fume-choked streets and boycott budget airlines. With this obscurantism there is no way the message of a more equitable distribution of the earth's dwindling resources can get through.

Julian Siann

Edinburgh

• Climate change

Not all dinosaurs were wiped out by the Chicxulub meteorite. We too may be in the midst of mass extinction

Everyone loves an apocalypse, and none more so than the one that sped the dinosaurs to their now legendary status. Having been a popular theory for 30 years, last week scientists finally reached a consensus that it was indeed the after-effects of a juggernaut meteorite crashing 65 million years ago into what we now call Chicxulub in Mexico that triggered the end of the dinosaurs' reign on Earth.

The reasons for loving this particular catastrophe are easy to understand. Dinosaurs are awesome. Giant meteorites are awesome. And of course, the combination of the two opened the door for the rise of the mammals. Our own story begins with that cataclysm.

"Consensus" has unfortunately become a dirty word outside the scientific world, thanks to those who disagree with the overwhelming majority of scientists about man-made global warming, but fail to offer any science in return. Unlike climate change, though, many issues remain with this extinction event. Sixty-five million years later, the pattern of extinction looks decidedly uneven. Dinosaurs were wiped out, but many similar-sized crocodiles survived. Amphibians managed to come out of this apocalypse relatively unscathed. Sharks survived, but plesiosaurs perished. Much work remains to be done.

Nevertheless, this consensus on the fate of the dinosaurs is welcomed by people such as me who worry about such things. But let's not get too attached to it. On the grand scale of extinctions, the Chicxulub meteorite is a drop in the ocean. There have been five major extinctions in the history of life. 251 million years ago was the big mama, erasing 95% of sea species and 70% of land life.

It is important to recognise that although 10-mile-wide rocks crashing from space are not the norm, extinction itself is. About 97% of all species that have ever existed currently do not. We may be in the midst of a mass extinction, though probably not on the scale of those 65 or 251 million years ago. Up to a third of all species are "committed to extinction", according to current models.

But it is the speed at which we are losing species that is truly significant. The explosion caused by the Chicxulub meteorite would have been enormous, melting rocks into glass, and vomiting forth mile-high tsunamis. But don't assume that the dinosaurs abruptly keeled over. In the aptly named Hell Creek in Montana, dinosaur fossils have been found dating from up to 40,000 years after the impact.

Climate change is also the planetary norm, but the rate at which the climate is changing since industrialisation is unprecedented. This is reason enough to accept the scientific consensus that we are the root cause, and the same goes for current extinctions.

We have evolved the capability to partially excuse ourselves from natural cataclysms, at least at a species level. Our ability to adapt and survive far outstrips the speed of the same process in natural selection. Should a colossal rock fall from the sky and block out the sun for a thousand years, the effect on humankind would be devastating, but not terminal. Should we continue to ravage the Earth's resources to the extent that human life is unsustainable, it is not in the realm of total fantasy for us to ditch this planet, and set up somewhere else in the universe.

But these are not reasons to be complacent. We exist as a part of this planet, not merely on it. The loss of biodiversity from a mass extinction will be devastating to everyone's lives. Unlike with the previous extinctions, we have the power to slow this current one. We will all have to change our lifestyles to adapt to the world that we have created, but by moderating our impact on extinction, that change won't have to be apocalyptic.

• Dinosaurs
• Conservation
• Endangered species
• Wildlife
• Biodiversity
• Zoology
• Evolution
• Animals

Despite the decision by the European Union last week to approve the cultivation of a GM potato, plant scientist Eoin Lettice argues that consumers will only accept the technology when it provides tangible benefits for them

Last week's decision by the European Commission to allow genetically modified potato varieties to be grown in some European Union countries concludes a 13-year campaign by the German chemical company BASF.

Ordinary potatoes produce two kinds of starch, but the GM potato Amflora only produces the economically useful form, amylopectin, which is used in the paper, textiles and adhesives industries. Production of the uneconomic form, amylase, has been turned off by genetic modification, so the useful starch doesn't need to be separated from the useless form during processing.

BASF says that while starch from its GM potato will not be used in human food, it may use the product in animal feed.

What particularly worries opponents of GM technology, however, is that Amflora carries an extra gene that makes the potato resistant to the antibiotics neomycin and kanamycin.

Why is it there? GM plants are produced by inserting novel genes into individual plant cells and then growing the cells into whole plants in the laboratory. Gene insertion can be achieved by using a bacterium to "ferry" it into the cell or by blasting it in using a gene gun. Alternatively, the tough plant cell wall can be stripped off and the gene can be inserted into this "naked" cell.

Regardless of the technique used, not all of the plant cells will take up the novel gene and incorporate it into their own DNA – perhaps just five cells out of every thousand. Tagging the novel gene with an antibiotic resistance gene allows modified cells to be singled out, because they will be resistant to a specific range of antibiotics.

This has been a source of concern for campaigners, but in June 2009, the European Food Safety Authority ruled that marker genes like this are unlikely to cause adverse effects on human health and the environment. As a result of limitations in sampling and detection it was unable to be conclusive, but the authority emphasised that it considered Amflora to be safe.

BASF first submitted its Amflora potato for approval in 1996. However, an EU-wide moratorium on GM between 1998 and 2004 delayed the process substantially.

When the potato was resubmitted for approval after the moratorium ended, progress was so slow that in 2008 BASF filed an action against the EC in the European Court of First Instance for "failure to act" and decide on the issue despite the European Food Safety Authority saying in two separate reports that the product was as safe as any conventional potato.

The company claimed that the previous commissioner, Stavros Dimas, "unjustifiably delayed" the decision on several occasions.

Now, within weeks of stepping into the role, the new European Commissioner for Health and Consumer Policy, John Dalli, has given the green light for planting to begin. BASF says the potatoes will be grown in Germany and the Czech Republic this year, and in Sweden and the Netherlands in 2011.

Opponents of GM technology have been quick to denounce the decision, with Greenpeace saying that Dalli has "steamrolled" a decision through. Given that the potato variety in question has undergone 13 years of testing since its first submission, this analogy might be better applied to the lumbering decision-making process in Europe rather than this final decisive move by the new commissioner.

At the root of this issue is consumers' wariness about GM foodstuffs and GM organisms in general. Consumers genuinely do not see the worth of GM products, which is why there is a need to move beyond crops that confer benefits to industry and growers alone towards second-generation GM that produces added health and nutritional benefits for consumers.

Hans Kast, president and CEO of BASF Plant Science, is on record as saying that the Amflora potato could potentially earn European farmers an extra €100 million annually. The company has also pointed out that it is losing between €20m and €30m in licence income for every lost cultivation season.

Perhaps I'm being presumptuous, but I can't imagine many Irish or European consumers lying awake at night worrying about lost revenues for BASF. What Irish consumers are interested in, however, are real and tangible benefits from their foods.

In a survey in 2005 by Ireland's Agriculture and Food Development Authority, 42% of consumers questioned indicated that they would consider purchasing a hypothetical GM-produced yoghurt if it had anti-cancer properties. In the same study, 44% of consumers said that they would use a GM-produced dairy spread if it had anti-cancer properties.

"Second generation" GM crops also have a role to play in developing countries, with the development of fortified foodstuffs such as "golden rice" to counteract malnutrition. A new variety of Golden Rice has been engineered to produce even more pro-vitamin A to combat vitamin A deficiency.

Undoubtedly, some British and Irish consumers, in common with their European counterparts, are reluctant to consume GM crops and see them growing in their countries. The focus of industry on benefits to the grower and seed producer rather than on consumer-centred benefits will prolong this reluctance and hamper the innovation in our food and agriculture industries that is so badly needed.

Eoin Lettice is a lecturer in the department of zoology, ecology and plant science at University College Cork, Ireland. He specialises in the control of plant pests and diseases

• Genetics
• Agriculture
• Controversies in science
• Food
• GM

As China selects two women to train female potential astronauts, an expert from the country's airforce claims women will deal better with space travel than men, citing better communication skills and the ability to deal with loneliness. Do you agree?

At post-mortem, most elderly men have traces of prostate cancer but have died of other causes

There is a much-publicised screening test for early prostate cancer, but GPs hesitate before ordering the test on demand. A slightly raised PSA (a protein that healthy prostates produce in small amounts) may indicate early prostate cancer, but it will not tell you what to do about it. Surgical removal of the prostate has a mortality rate and may cause unpleasant side-effects, like impotence and incontinence. At post-mortem, most elderly men have traces of prostate cancer but have died of other causes. We would have done them no favours, if we had removed their prostates.

I saw Ernest, a 67 year old man, three moths ago. His brother, aged 60, had just been found to have inoperable prostate cancer, so Ernest wanted a check. He did not have much in the way of symptoms. His prostate felt soft and benign but his PSA blood test came back slightly raised. A biopsy showed prostate cancer but it was very early and had not spread.

There was talk of "watch and wait" but Ernest could not contemplate that. The urologist recommended an open prostatectomy. Ernest consulted Dr Google. He saw another urologist privately who does laparoscopic prostatectomies. This procedure, still in its infancy in the UK, looks promising and the urologists who are doing it are keen to practise. He saw a radiation oncologist privately. She mentioned brachytherapy, a specialised form of internal radiotherapy. The surgeons, who both talked of a "complete" cure, told Ernest that radiotherapy brought an increased risk of rectal cancer, and the possibility of chronic diarrhoea and urinary frequency. The radiotherapist talked of impotence and incontinence as a risk of surgery. The open prostatectomy surgeon talked of "tried and tested" procedures. The laparoscopic surgeon talked of the reduced risks of key-hole surgery.

Ernest did not know what to do. You could make good arguments for each treatment that had been offered. Or you can go to Paris where they are playing with lasers. Ernest said, "I've seen lots of specialists; they are all charming but I got the feeling that they are all selling their wares. What would you do, doc?"

If I was fit, like Ernest, I would have the open prostatectomy. Laparoscopic prostatectomy is not widely available on the NHS and in any case I am not sure I would want to be the material upon which surgeons learn a new technique. Ask me about it in a year or two.

Ernest had the open operation six weeks ago. He is not incontinent. As regards sexual performance, he has not yet tried, but he says there have been "stirrings". He is doing well. His PSA is zero and he feels he is cured. The only thing I am not sure of is whether it would have been better if we had never measured his PSA in the first place.

Names and some details have been changed. prostate-cancer.org.uk.

• Doctors
• Prostate cancer
• NHS
• Health
• Health & wellbeing
• Ageing

Huw Irranca-Davies, wildlife minister, tells Jon Dennis about a plan to introduce an insect predator to attack Japanese knotweed

How can normal people be made to act heroically?

In paying tribute to Michael Foot last week, David Cameron used an intriguingly double-edged phrase. He described the former Labour leader as "almost the last link to a more heroic age in politics" – a duly respectful compliment, but one that also hinted that Foot was from a bygone era where politics was done in brash primary colours rather than the thoughtful shades used today.

Of all the virtues, heroism is now the most remote. Heroes are either mythic or historical characters (Achilles or Gandhi) or they are superhuman (Spider-Man, or even 9/11 firefighters). What they are not is one of us. Our age has role models and it has celebrities, but it has no room for heroes.

Fighting to revive heroism is Philip Zimbardo, the septuagenarian who is probably the most famous living psychologist in the world. Zimbardo built his career on the study of evil; in 1971, he led the Stanford Prison Experiment, where long-haired students were put in a mock jail and divvied up as prisoners or guards at random. Within a few days, the "guards" were humiliating their "prisoners", refusing some permission to urinate and subjecting others to simulated sodomy.

That experiment and others convinced Zimbardo that ordinary people could be driven to evil acts if put in horrific situations. His latest work flips that principle and asks: how can normal folk be made to behave heroically? By heroism, the psychologist does not mean altruism but the risking of one's safety or status, sometimes for an ideal. Zimbardo talks of the "banality of heroism" – a neat inversion of Hannah Arendt's observation that the Nazi Adolf Eichman demonstrated "the banality of evil" – and points out that social scientists have done acres of research on evil but barely any on heroism. And to that end, he has been slaving away – heroically, one might say – lecturing policy-makers and raising research funds.

There is more to this project than academic papers, however. Matt Langdon works with Zimbardo and, as head of the Hero Construction Company, runs his own character-building classes for 10-14 year olds. "I always tell them that the opposite of a hero isn't a villain – it's a bystander," he says.

• Psychology

'The idea of a simple and readily available mask came to me after the Chernobyl nuclear accident in Ukraine'

Last October, at Harvard University, I was awarded the Ig Nobel prize for public health for inventing the Emergency Bra, an item of lingerie that, in case of an emergency, can be quickly transformed into two protective respiratory face masks.

Don't get too excited, boys: this can be done without removing any clothes.

My Ig Nobel nomination came as a pleasant surprise. And I recognised that this competitive prize for "scientific achievements that first make people laugh and then make them think" is hugely popular and a great opportunity to deliver a message on emergency preparedness to the public.

I admit that disaster preparedness is not the most enthralling discussion topic, but it is obvious why my invention is well suited for the Ig Nobel prize. Almost everyone who hears about it first laughs, then appreciates the underlying idea: an effective personal protective device needs to be simple, economical, and readily available.

The idea of a simple and readily available mask came to me after the Chernobyl nuclear accident in Ukraine. I was a young doctor at the time treating children relocated from the contaminated zone. I knew that the radioactive Iodine-131 aerosol released from the damaged reactor was a major contributor to the internal radiation dose of the affected population. My experiences led me to question why simple protective face masks were not available. As the mother of a one-year-old son, I was convinced women should have readily available means of protecting their children.

Because most women wear one all the time – and it can provide two face masks – I considered using a standard bra as the basis for such a personal protective device and designed my first prototype.

In 2001 I was shocked to see the photographs of victims of the 9/11 tragedy in New York holding pieces of cloth over their faces while running away from the disaster. Evacuation from similar emergencies would be easier if individuals had readily available face masks to protect their airways and free their hands. It was at that poiunt that I decided to proceed with commercialisation of the Emergency Bra.

For a medical scientist with no business experience, this was a challenge. But thanks to media exposure, I have received feedback showing that demand for the Emergency Bra is high. With the support of colleagues, students, family and friends, I re-prioritised my academic life and have started to manufacture the Emergency Bra, which will be available in the very near future at www.ebbra.com. The bra can provide a person with a critical time window to escape from fires, explosions, natural disasters and biological and radiological terrorist attacks (including a "dirty bomb"). As well as protecting against inhalation of harmful airborne particles and freeing victims' hands while they escape, it can decrease the chances of a panic attack in large crowds by providing individuals with a sense of security.

For the Ig Nobel award ceremony, I designed a hot pink Emergency Bra that has now been dubbed the Harvard model. I demonstrated it on Nobel laureates Wolfgang Ketterle (Nobel prize for physics, 2001), Orhan Pamuk (literature, 2006) and Paul Krugman (economics, 2008). Although they were not expecting it, they seemed to enjoy the demonstration.

During the forthcoming UK Ig Nobel tour this month, I will also demonstrate that the Emergency Bra is not only an effective, economical and readily available personal protective device but that, first and foremost, it is a beautiful piece of lingerie. Its additional function of personal protection does not interfere with its aesthetics or its main purpose.

I have no doubt my demonstrations will generate some laughs. However, I also look forward to addressing some serious questions from the British public. I hope audiences at Oxford University, Imperial College and elsewhere will leave thinking about the potential risks they face. I will consider my goals to be accomplished if I make people remember the importance of being prepared for the unexpected.

• Dr Elena Bodnar is director of the Trauma Risk Management Research Institute, Chicago

• For more information about the Ig Nobel tour, go to improbable.com/ improbable-research-shows/ig-uk-tour Improbable research, page 8

• Research
• Higher education
• Emergency planning
• Science prizes

Chosen insect feeds on invasive species but not other closely related plants and crops

Biological warfare is to be declared on an alien invader, Japanese knotweed, that swamps gardens and rivers, with the release of an insect to eat the virulent weed.

The decision by the Department for Environment, Food and Rural Affairs is the first allowing one non-native species, a flying insect resembling a miniature moth, to control the seemingly unstoppable spread of an alien plant.

However, it is likely to cause concern among wildlife lovers because of a long history of human interventions in the natural world ending in failure, and sometimes causing worse problems than the original, as with the cane toad in Australia.

In a public consultation by Defra last year about 20 responses opposed the scheme, though 42 were in favour.

The wildlife minister, Huw Irranca-Davies, said the fast-growing Japanese knotweed was estimated to cost £150m a year to control, and was able to grow through buildings and roads.

Fallopia japonica has also been blamed for flooding, by causing erosion to river banks and clogging up streams with dead plants.

"This project is not only ground-breaking, it offers real hope that we can redress the balance," said Irranca-Davies.

Experts estimated in 2003 that it would cost £1.5bn to fund a physical clearance campaign for Japanese knotweed.

Laboratory tests were started on pests from Japan which control the knotweed by feeding on sap from its stems, causing the plant to die back.

The tests showed the chosen Aphalara itadori did not eat any other species, including closely related British plants and important crops.

The psyllids – or plant-jumping lice, which grows to only 2-2.5mm – will be released at two sites initially, under close supervision.

If these outdoor trials are a success the trials will be extended to another six sites, none of which Defra will disclose.

The concept is similar to biological pest control practised by some farmers, using predator insects to control crop pests. The non-native predatory beetle Rhizophagus grandis was also released in Britain under licence in the mid-1980s to tackle the invasive alien spruce bark beetle (Dendroctonus micans).

On conservation and wildlife internet forums, opponents of the idea said they feared the impact on other native wildlife, for example species that might start feeding on the psyllids. One blogger compared the risk to the traditional nursery rhyme "I know an old lady who swallowed a fly" in reference to the long pursuit of one animal to destroy another – ending in the lady swallowing a horse: "She's dead of course." The Global Invasive Species Programme said that despite a few well-known failures, a third of biological control programmes to tackle pests and weeds were judged successes, and the system was often considered more "permanent, efficient, environmentally sustainable and relatively cheap" than using chemicals or mechanical removal.

"While there are some risks, which still may be considered by some to be unacceptable, biological control is increasingly viewed as being the preferred management strategy for invasive species, wherever possible, and in the case of biological weed control specifically, it has an enviable safety record," said Sarah Simons, Gisp's executive director.

Japanese knotweed, which is native to Japan, Taiwan and China, was introduced by botanists into Britain in the 19th century as an ornamental plant. It grows at up to a metre a month, and a fragment of just 0.8 grams can grow into a new plant. Invasive predators have become a global problem and are among the top causes of global species threats and extinctions according to conservation experts.

The Royal Horticultural Society suggests gardeners destroy knotweed using glyphosate-based weed-killers or by digging out the roots and cutting back regrowth, however it warns that the process can take several seasons. Experts stress that uprooted plants must be destroyed carefully to avoid spreading. "Eradication requires steely determination," says the RHS.

• Invasive species
• Plants
• Insects
• Pesticides
• Biology

There is no simple way to battle public hostility to climate research. As the psychologists show, facts barely sway us anyway

There is one question that no one who denies manmade climate change wants to answer: what would it take to persuade you? In most cases the answer seems to be nothing. No level of evidence can shake the growing belief that climate science is a giant conspiracy codded up by boffins and governments to tax and control us. The new study by the Met Office, which paints an even grimmer picture than the Intergovernmental Panel on Climate Change, will do nothing to change this view.

The attack on climate scientists is now widening to an all-out war on science. Writing recently for the Telegraph, the columnist Gerald Warner dismissed scientists as "white-coated prima donnas and narcissists … pointy-heads in lab coats [who] have reassumed the role of mad cranks … The public is no longer in awe of scientists. Like squabbling evangelical churches in the 19th century, they can form as many schismatic sects as they like, nobody is listening to them any more."

Views like this can be explained partly as the revenge of the humanities students. There is scarcely an editor or executive in any major media company – and precious few journalists – with a science degree, yet everyone knows that the anoraks are taking over the world. But the problem is compounded by complexity. Arthur C Clarke remarked that "any sufficiently advanced technology is indistinguishable from magic". He might have added that any sufficiently advanced expertise is indistinguishable from gobbledegook. Scientific specialisation is now so extreme that even people studying neighbouring subjects within the same discipline can no longer understand each other. The detail of modern science is incomprehensible to almost everyone, which means that we have to take what scientists say on trust. Yet science tells us to trust nothing, to believe only what can be demonstrated. This contradiction is fatal to public confidence.

Distrust has been multiplied by the publishers of scientific journals, whose monopolistic practices make the supermarkets look like angels, and which are long overdue for a referral to the Competition Commission. They pay nothing for most of the material they publish, yet, unless you are attached to an academic institute, they'll charge you £20 or more for access to a single article. In some cases they charge libraries tens of thousands for an annual subscription. If scientists want people at least to try to understand their work, they should raise a full-scale revolt against the journals that publish them. It is no longer acceptable for the guardians of knowledge to behave like 19th-century gamekeepers, chasing the proles out of the grand estates.

But there's a deeper suspicion here as well. Popular mythology – from Faust through Frankenstein to Dr No – casts scientists as sinister schemers, harnessing the dark arts to further their diabolical powers. Sometimes this isn't far from the truth. Some use their genius to weaponise anthrax for the US and Russian governments. Some isolate terminator genes for biotech companies, to prevent farmers from saving their own seed. Some lend their names to articles ghostwritten by pharmaceutical companies, which mislead doctors about the drugs they sell. Until there is a global code of practice or a Hippocratic oath binding scientists to do no harm, the reputation of science will be dragged through the dirt by researchers who devise new means of hurting us.

Yesterday in the Guardian Peter Preston called for a prophet to lead us out of the wilderness. "We need one passionate, persuasive scientist who can connect and convince … We need to be taught to believe by a true believer." Would it work? No. Look at the hatred and derision the passionate and persuasive Al Gore attracts. The problem is not only that most climate scientists can speak no recognisable human language, but also the expectation that people are amenable to persuasion.

In 2008 the Washington Post summarised recent psychological research on misinformation. This shows that in some cases debunking a false story can increase the number of people who believe it. In one study, 34% of conservatives who were told about the Bush government's claims that Iraq had weapons of mass destruction were inclined to believe them. But among those who were shown that the government's claims were later comprehensively refuted by the Duelfer report, 64% ended up believing that Iraq had weapons of mass destruction.

There's a possible explanation in an article published by Nature in January. It shows that people tend to "take their cue about what they should feel, and hence believe, from the cheers and boos of the home crowd". Those who see themselves as individualists and those who respect authority, for instance, "tend to dismiss evidence of environmental risks, because the widespread acceptance of such evidence would lead to restrictions on commerce and industry, activities they admire". Those with more egalitarian values are "more inclined to believe that such activities pose unacceptable risks and should be restricted".

These divisions, researchers have found, are better at explaining different responses to information than any other factor. Our ideological filters encourage us to interpret new evidence in ways that reinforce our beliefs. "As a result, groups with opposing values often become more polarised, not less, when exposed to scientifically sound information." The conservatives in the Iraq experiment might have reacted against something they associated with the Duelfer report, rather than the information it contained.

While this analysis rings true, the description of where the dividing line lies isn't quite right. It doesn't describe the odd position in which I find myself. Despite my iconoclastic, anti-corporate instincts, I spend much of my time defending the scientific establishment from attacks by the kind of rabble-rousers with whom I usually associate. My heart rebels against this project: I would rather be pelting scientists with eggs than trying to understand their datasets. But my beliefs oblige me to try to make sense of the science and to explain its implications. This turns out to be the most divisive project I've ever engaged in. The more I stick to the facts, the more virulent the abuse becomes.

This doesn't bother me – I have a hide like a glyptodon – but it reinforces the disturbing possibility that nothing works. The research discussed in the Nature paper shows that when scientists dress soberly, shave off their beards and give their papers conservative titles, they can reach to the other side. But in doing so they will surely alienate people who would otherwise be inclined to trust them. As the MMR saga shows, people who mistrust authority are just as likely to kick against science as those who respect it.

Perhaps we have to accept that there is no simple solution to public disbelief in science. The battle over climate change suggests that the more clearly you spell the problem out, the more you turn people away. If they don't want to know, nothing and no one will reach them. There goes my life's work.

• Climate change
• Climate change
• Climate change scepticism
• Intergovernmental Panel on Climate Change (IPCC)
• Hacked climate science emails

Three species thought extinct, including a caddisfly and yellow-spotted bell frog, have been sighted in the UK and Australia

• Humans driving extinction faster than species can evolve, say experts

Three species thought to be extinct have been found again, to the delight of conservationists.

In the UK, the rare ghost orchid, declared extinct in this country just last year, has been found in England, and a caddisfly – a small flying insect – last seen more than a century ago has been discovered again in Scotland. On the global stage the yellow-spotted bell frog, presumed "possibly extinct" by the International Union for the Conservation of Nature, has been seen on a creek-bed in Australia.

The good news stories follow a warning by a leading IUCN expert that humans are now driving plants and animals to extinction faster than new species can evolve.

Simon Stuart, the IUCN expert who chairs the Species Survival Commission which declares species endangered or extinct, said that although roughly one "possibly extinct" species each year was re-discovered, many more plants and animals were added to the list.

There will also be continuing concern for species that are re-discovered in very small numbers. For example only a single 5cm high ghost orchid was found by the botanists who revealed it is still alive in the UK. The sighting of the caddisfly by a PhD student beside a river in north-west Scotland – 350 miles north of the previous record, according to the conservation charity Buglife – could further suggest the influence of climate change in driving species out of their traditional habitats, something some plants and animals will be able to adapt to better than others.

"The whole point of the 'possibly extinct' list is they can come in and out," said Stuart. "But we're adding species on to the 'possibly extinct' list much faster than we're taking them off it."

The IUCN has much stricter rules about declaring a species fully extinct, including that it must have been actively searched for by teams of experts in the field. However in 2008 the Switzerland-based organisation did have to move the Miles' robber frog (Craugastor milesi) from the extinct to critically endangered list after a single specimen was found in Honduras.

Among the reasons conservationists dislike a species being declared extinct are that it is no longer possible to get money to research and preserve its habitat. The locations of the orchid and the Australian frog are both being kept secret to protect them, however one of the bell frogs and a tadpole have been taken to Taronga zoo in Sydney for a captive breeding programme.

• Conservation
• Endangered habitats
• Endangered species
• Wildlife
• Insects
• Plants
• Biodiversity
• Animals

Officials concerned space flight might affect fertility of first Chinese women to go into orbit

They are, of course, in peak physical condition, with the flying skills required of any air force ace. But China's first female astronauts have faced an extra challenge: they had to be mothers to qualify for the country's prestigious space programme.

Two women and five men have been selected as the next generation to go into space, a Hong Kong newspaper reported today, citing an unnamed military source.

Xu Xianrong, an expert at the air force general hospital, said women had advantages as astronauts over men because they were more mentally stable, better able to bear loneliness and had better communication skills.

The insistence that they should also be wives and mothers does not relate to their multi-tasking abilities. Officials are concerned that space flight might affect their fertility.

"It's out of the consideration of being responsible for the female pilots," Xu told the state news agency Xinhua. "Though there is little evidence on how the space experience will affect the female constitution, we have to be extra cautious. After all, it's unprecedented in China."

The authorities have yet to disclose the names of the would-be astronauts, but all are between 27 and 34. Hong Kong's Wen Wei Po newspaper identified five of the 15 women shortlisted, who it said were all from Shandong province.

Sun Jing is described as a "flying maniac", while Xing Lei was the only straight-A student in pilot school. Cao Yanyan comes from a high-flying family; both her husband and mother-in-law are said to be outstanding pilots.

Liu Lu is multi-talented and a lover of literature, while Wang Yaping helped with recovery efforts after the Sichuan earthquake in 2008 and seeded clouds to ensure clear skies for the Beijing Olympics.

Qi Faren, a delegate to the Chinese political advisory body currently meeting in Beijing, told state media that one or two women were currently receiving training for the space programme, but had no timetable for launch. They face up to five years of intensive training.

Last year Sui Guosheng, an officer in charge of recruitment with the air force, said he expected to see a woman in space by 2012 – nine years after Yang Liwei became the first Chinese citizen to lift off.

Would-be astronauts are vetted so carefully that even bad breath can scupper their chances, a medical adviser revealed last year. Many of those who make the grade and undertake the gruelling training programme never actually make it into space.

Valentina Tereshkova, from the then USSR, became the first woman in space in 1963. Nasa barred women for years – despite the fact female aspirants scored better on several medical tests than male counterparts – and it was only in 1983 that Sally Ride became the first American woman to go into space.

• China
• Space

Research shows vitamin D, produced by skin when exposed to ultraviolet light, associated with reduced rate of renal cancer

Men who work outdoors, enabling their bodies to create vitamins through exposure to sunlight, have a reduced risk of kidney cancer, researchers said today.

In the largest study of its kind, scientists found that vitamin D – produced by the skin when exposed to ultraviolet light – was associated with a reduced rate of renal cancer of up to 73% among men.

However, the study, published by the American Cancer Society, found that the reduced risk only applied to men – there was no drop in renal cancer among the women studied who worked outdoors.

The researchers, from the National Cancer Institute in the US, said the study of 2,500 workers in central Europe supported emerging evidence that the prevalence of a number of cancers, including breast, ovarian and colorectal cancer, was lower when people were exposed to ultraviolet light.

They said vitamin D, a known anti-carcinogenic, was carried by the body to the liver and on to the kidneys, and recommended further research.

"Scientific evidence suggests that vitamin D, which is generally made in the body after exposure to the sunlight, may help prevent a number of diseases, including cancer," the research author, Sara Karami, said.

"In our study, we used job titles to estimate sunlight exposure at work. We observed that men with high estimated levels of sunlight exposure had a lower risk of kidney cancer than men who had lower estimated sunlight exposure at work."

Scientists have monitored an increase in renal cell carcinoma (RCC), the main form of kidney cancer, in the US and globally over the past 20 years.

A reduction in vitamin D – probably caused by many more people having sedentary lifestyles and indoor jobs – is believed to be a likely contributory factor.

The researchers studied more than 2,500 workers of Caucasian descent in Russia, Romania, Poland and the Czech Republic, splitting them into three groups according to exposure to daylight in their jobs.

A significant fall of up to 38% in the risk of RCC was found with increasing occupational UV exposure among men.

In northern-most regions, that increased to a 73% drop. But after finding no similar decrease in the risk for women, Karami said: "We do not have an explanation for the apparent differences in risk between men and women".

"Biological or behavioural differences between men and women may play a role. For example, hormonal differences may influence the body's response to sunlight exposure, and men may be prone to working outdoors while shirtless."

Although some foods contain vitamin D, the majority of people receive up to 90% of the chemical through exposure to ultraviolet light.

Farm workers and those who receive strong UV light reflected from the sea were in the highest category. Those in high-sunlight jobs were assumed to receive double the intensity of sunlight to those in low-exposure jobs.

Despite the findings, the researchers warned against ignoring the "well-documented risks" of skin cancer resulting from excess exposure to the sun.

"There are no public health recommendations from this study. Men and women should continue to consult their healthcare providers regarding the appropriate amount of sun exposure, weighing the well-documented risks between sun exposure and skin cancer risk," Karami said.

Healthy Caucasians can generate a full dose of vitamin D with 10-20 minutes' exposure to strong sunlight on unprotected skin. After that, photo-degradation ensures no higher levels are created.

The anti-carcinogenic properties of vitamin D include the prevention of tumour cell replication.

• Cancer
• Cancer
• United States
• Russia
• Romania
• Poland
• Czech Republic
• All sectors

Brain Cox gets choked up by solar eclipses and the northern lights. I am totally smitten

Particle physicists aren't supposed to be like Professor Brian Cox. He's young and handsome, has a nice smile and fashionable hair, more like a pop star than a scientist. As it happens, he was once a pop star, of sorts. He played keyboards in D:Ream – you know, Things Can Only Get Better, the New Labour anthem, urgh. Things didn't get better for D:Ream, and now Cox does astrophysics on the telly, with a new series called Wonders of the Solar System (BBC2, Sunday).

It must have been a eureka moment for whoever discovered him, as he's very good. And not just because he's totty, with a nice, soft Lancashire accent (steady!). But because he clearly feels a huge amount of love and wonder for what he does, and he talks about it all in a way that you wouldn't necessarily expect a physicist to talk. The sun, the subject of this opener, is "a colossal fiery sphere of tortured matter". An eclipse, which he witnesses from the banks of the Ganges at Varanasi, is "the solar system coming down and grabbing you by the throat". And it grabs his throat with such force it has him close to tears. He knows that aurora borealis, the northern lights, are the visual manifestation of the earth's magnetic fields protecting us from the solar wind, "but the green shafts of light look like spirits drifting up from the mountain into heaven".

Spirits? Heaven? What's going on? There was none of that in physics at my school. But then Mr Darling had never been a sort-of pop star. Couldn't have been further from it, actually.

Cox's romantic, lyrical approach to astrophysics all adds up to an experience that feels less like homework and more like having a story told to you. A really good story, too. Who knew that the sun had seasons, or that when clumps of hydrogen collapse under their own gravity, a star is born? Is that how Cox came about, I wonder. Oh God, this is pathetic, I'm clearly smitten.

Moving swiftly along then, to A Kick in the Head: The Lure of Las Vegas (BBC2, Saturday), with Alan Yentob, who's not smiting anyone, but does fancy himself as a bit of a wordsmith. Vegas is "like a mirage on the horizon, an oasis, a celestial city," he says, before slipping into Genesis – the first book of the old testamant, not the prog rock band. Yentob does like to hang out with rock stars though, and it's not long before he's in the studio with Killers frontman Brandon Flowers, nodding along to the beat. Maybe don't do that Alan, it's not very dignified.

This film was too long by 15 minutes. An hour would have been right. If you cut all the shots of Alan – driving around in his rental car with his shades on, wandering round a graveyard for neon signs, losing money at the blackjack table – that's about what you would have had. But someone, probably Alan Yentob, has decided that Alan Yentob should be very much a part of the film. Maybe it's to reassure us that he was actually there.

Anyway, monstrous egomania aside, this was a terrific portrait of the place: part history, part art history, part psychoanalysis. With contributions from all the right people, apart from Sinatra, Elvis and Howard Hughes, of course. The best – and truest – lines come from an Englishman, Mike Figgis, director of Leaving Las Vegas. Vegas, he said, was "designed for the losers of America to lose money, and to eat as much crap as possible. Like the toilet of the United States, just with great lighting." Very true.

The Undercover Princesses (BBC3, Sunday) is fun. Three royal ladies, from Uganda, India and Germany, go out and about in Chelmsford. They're not just pretending not to be princesses; they're single and they're on the pull, which shouldn't be hard to manage in Essex. Trouble is, they have no idea how to, except for Princess Xenia of Saxony, who looks like she's had some experience in the field. But poor Princess Nvannungi Sheillah from the Buganda Kingdom of Uganda, and Princess Aliya Sultana of Balasinor, know nothing of karaoke. Or of going out wearing almost nothing, downing dozens of Bacardi Breezers and then sticking their tongues down strangers' throats. They'll learn, though. I hope so, anyway, not just for their sakes, but for some Essex geezer who could suddenly find himself King of Buganda.

• Television
• Documentary
• Astronomy
• Space
• People in science

Science writer Simon Singh and Tracey Brown from Sense About Science tell us about Libel Reform Week and the campaign to change Britain's libel laws and protect scientific freedom of expression.

Simon is currently locked in a legal battle over a comment piece published in the Guardian.

Matthew Applegate, aka Pixelh8, is performing an audiovisual study as part of Cambridge Science Festival. We went along to the Institute of Astronomy to hear the telescopes he used as his musical instruments.

Ian Sample speaks to Kees van Deemter about the importance of being vague. Kees is trying to program computers to be a little more ... erm ... fuzzy? His new book Not Exactly: In Praise of Vagueness is out now.

The Guardian's Nell Boase joins Alok in the studio.

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Conservationists say rate of new species slower than diversity loss caused by the destruction of habitats and climate change

• Ghost orchid comes back from extinction

For the first time since the dinosaurs disappeared, humans are driving animals and plants to extinction faster than new species can evolve, one of the world's experts on biodiversity has warned.

Conservation experts have already signalled that the world is in the grip of the "sixth great extinction" of species, driven by the destruction of natural habitats, hunting, the spread of alien predators and disease, and climate change.

However until recently it has been hoped that the rate at which new species were evolving could keep pace with the loss of diversity of life.

Speaking in advance of two reports next week on the state of wildlife in Britain and Europe, Simon Stuart, chair of the Species Survival Commission for the International Union for the Conservation of Nature – the body which officially declares species threatened and extinct – said that point had now "almost certainly" been crossed.

"Measuring the rate at which new species evolve is difficult, but there's no question that the current extinction rates are faster than that; I think it's inevitable," said Stuart.

The IUCN created shock waves with its major assessment of the world's biodiversity in 2004, which calculated that the rate of extinction had reached 100-1,000 times that suggested by the fossil records before humans.

No formal calculations have been published since, but conservationists agree the rate of loss has increased since then, and Stuart said it was possible that the dramatic predictions of experts like the renowned Harvard biologist E O Wilson, that the rate of loss could reach 10,000 times the background rate in two decades, could be correct.

"All the evidence is he's right," said Stuart. "Some people claim it already is that ... things can only have deteriorated because of the drivers of the losses, such as habitat loss and climate change, all getting worse. But we haven't measured extinction rates again since 2004 and because our current estimates contain a tenfold range there has to be a very big deterioration or improvement to pick up a change."

Extinction is part of the constant evolution of life, and only 2-4% of the species that have ever lived on Earth are thought to be alive today. However fossil records suggest that for most of the planet's 3.5bn year history the steady rate of loss of species is thought to be about one in every million species each year.

Only 869 extinctions have been formally recorded since 1500, however, because scientists have only "described" nearly 2m of an estimated 5-30m species around the world, and only assessed the conservation status of 3% of those, the global rate of extinction is extrapolated from the rate of loss among species which are known. In this way the IUCN calculated in 2004 that the rate of loss had risen to 100-1,000 per millions species annually – a situation comparable to the five previous "mass extinctions" – the last of which was when the dinosaurs were wiped out about 65m years ago.

Critics, including The Skeptical Environmentalist author, Bjørn Lomborg, have argued that because such figures rely on so many estimates of the number of underlying species and the past rate of extinctions based on fossil records of marine animals, the huge margins for error make these figures too unreliable to form the basis of expensive conservation actions.

However Stuart said that the IUCN figure was likely to be an underestimate of the problem, because scientists are very reluctant to declare species extinct even when they have sometimes not been seen for decades, and because few of the world's plants, fungi and invertebrates have yet been formally recorded and assessed.

The calculated increase in the extinction rate should also be compared to another study of thresholds of resilience for the natural world by Swedish scientists, who warned that anything over 10 times the background rate of extinction – 10 species in every million per year – was above the limit that could be tolerated if the world was to be safe for humans, said Stuart.

"No one's claiming it's as small as 10 times," he said. "There are uncertainties all the way down; the only thing we're certain about is the extent is way beyond what's natural and it's getting worse."

Many more species are "discovered" every year around the world, than are recorded extinct, but these "new" plants and animals are existing species found by humans for the first time, not newly evolved species.

In addition to extinctions, the IUCN has listed 208 species as "possibly extinct", some of which have not been seen for decades. Nearly 17,300 species are considered under threat, some in such small populations that only successful conservation action can stop them from becoming extinct in future. This includes one-in-five mammals assessed, one-in-eight birds, one-in-three amphibians, and one-in-four corals.

Later this year the Convention on Biological Diversity is expected to formally declare that the pledge by world leaders in 2002 to reduce the rate of biodiversity loss by 2010 has not been met, and to agree new, stronger targets.

Despite the worsening problem, and the increasing threat of climate change, experts stress that understanding of the problems which drive plants and animals to extinction has improved greatly, and that targeted conservation can be successful in saving species from likely extinction in the wild.

This year has been declared the International Year of Biodiversity and it is also hoped that a major UN report this summer, on the economics of ecosystems and biodiversity, will encourage governments to devote more funds to conservation.

Professor Norman MacLeod, keeper of palaeontology at the Natural History Museum in London, cautioned that when fossil experts find evidence of a great extinction it can appear in a layer of rock covering perhaps 10,000 years, so they cannot say for sure if there was a sudden crisis or a build up of abnormally high extinction rates over centuries or millennia.

For this reason, the "mathematical artefacts" of extinction estimates were not sufficient to be certain about the current state of extinction, said MacLeod.

"If things aren't falling dead at your feel that doesn't mean you're not in the middle of a big extinction event," he said. "By the same token if the extinctions are and remain relatively modest then the changes, [even] aggregated over many years, are still going to end up a relatively modest extinction event."

The International Union for the Conservation of Nature (IUCN) lists 208 species as "possibly extinct", more than half of which are amphibians. They are defined as species which are "on the balance of evidence likely to be extinct, but for which there is a small chance that they may still be extant".

Kouprey (or Grey ox; Bos sauveli)

What: Wild cattle with horns that live in small herds

Domain: Mostly Cambodia; also Laos, Vietnam, Thailand

Population: No first-hand sightings since 1969

Main threats: hunting for meat and trade, livestock diseases and habitat destruction

Webbed-footed coqui (or stream coqui; Eleutherodactylus karlschmidti)

What: Large black frog living in mountain streams

Domain: East and west Puerto Rico

Population: Not seen since 1976

Main threats: Disease (chytridiomycosis), climate change and invasive predators

Golden coqui frog (Eleutherodactylus jasperi)

What: Small orange frog living in forest or open rocky areas

Domain: Sierra de Cayey, Puerto Rico

Population: No sightings since 1981

Main threats: Unknown but suspected habitat destruction, climate change, disease (chytridiomycosis) and invasive predators

Spix's macaw (or little blue macaw; Cyanopsitta spixii)

What: Bright blue birds with long tails and grey/white heads

Domain: Brazil

Population: The last known wild bird disappeared in 2000; there are 78 in captivity

Main threats: Destruction of the birds' favoured Tabebuia caraiba trees for nesting, and trapping

Café marron (Ramosmania rodriguesii)

What: White flowering shrub related to the coffee plant family

Domain: Island of Rodrigues, Republic of Mauritius

Population: A single wild plant is known

Main threats: Habitat loss, introduced grazing animals and alien plants

Source: IUCN and Royal Botanic Gardens Kew. To mark the International Year of Biodiversity, the IUCN is running a daily profile of a threatened species throughout 2010. See iucn.org.

• Conservation
• Endangered species
• Endangered habitats
• Wildlife
• Biodiversity
• Zoology
• Animals
• Plants
• Evolution

People are drifting into a lethal slumber on climate change. More of the same won't wake them up

It's an exceptionally inconvenient truth. Only one American in three believes that human beings are responsible for climate change: a polling result 10% down on where opinion rested the year before. Worse, the number of Americans who believe that climate change is a hoax or a scientific conspiracy – not doubting, just damned blank certain – has doubled since 2008. Add in those who assert that the changes, if any, are of "no significant concern", and you've got 30% of the US denying, scoffing and just walking on by.

Are the issues clearer, the people more committed, here in Britain? Call for the latest evidence from Ipsos Mori – and find that the proportion of UK adults who believe that global warming is "definitely" a reality has plummeted from 44% to 31% in the last 12 months. Figures like these, on both sides of the Atlantic, are getting more sceptical week by week. The real change of electoral climate is that fewer and fewer voters pay any heed to scientists and politicians.

It isn't hard to collate the factors that drive disillusion. Professors with a colloquial touch writing "awful" emails; a recession so tough that it blows future shock away; a cold, cold winter the Met Office didn't forecast; scientific angst about swine flu revealed as way over the top; dodgy figures, dodgy reporting, dodgy issues way up to UN level.

These are only a few of our least favourite things. Mix them together in the stew of pre-election politics, and the result is lethal inertia. Once upon a quite recent time, David Cameron seemed bent on playing a new green giant. Now he's just another family-friendly campaigner, keen on pressing pounds sterling into sweaty palms. Environmental issues have slithered down the greasy pole of public anxiety. They won't get much of a mention on the hustings in May: no fresh commitments, no crucial pledges. In one sense, the heat may by rising; in another, the heat is off.

And that, of course, is cause for very significant concern. Democracies move in particular ways. Voters have to clamber on board when sacrifices are required. They have to see the need for pain, to sense the danger of doing nothing. They have to lead their leaders as well as follow – once they switch off, nothing good happens easily, if at all.

An Obama stalled on healthcare reform in the Senate isn't going to be able to deliver sweeping global warming policies. He may not be George Bush, but he already seems to know when he's on a loser. And, without him, you can write the Chinese or Indian scripts. You can tell that the follow-ups to Copenhagen will be feebler, not stronger: true cause for despair. Kick away any mass impetus for tackling climate change as schedules of imminent necessity fade and review panels plod across the wastelands of borrowed time.

What's to be done (except wait for a natural disaster that ends all argument – and much else besides)? First, through gritted teeth, say what won't work, what's been tried already and failed.

More jaw and Gore from politicians can't cut it. They have come to seem secondhand sources, merely parroting a frail scientific thesis. That goes, alas, for journalists, too – and for pressure groups issuing lurid warnings or staging angry demos. Those of us who are convinced, who believe in the necessity of action, haven't changed our minds. But we're not the point. The audience that matters is out there, sleeping or drifting. And rousing it will demand something different, not more of the same.

Yet more of the same is exactly what we seem to be getting. More re-examinations of existing evidence, monitored by the people who failed to monitor it last time. More supposedly transparent attempts to say precisely when Himalayan glaciers will melt. More United Nations panels, flying lugubriously hither and yon in the cause of consensus. More declarations signed by hundreds of scientists on behalf of a notional "scientific community" (rather like letters to editors from umpteen economists urging cuts or no cuts).

None of it has a ring of renewed confidence. And the plain fact is that we surely need a prophet, not yet another committee. We need one passionate, persuasive scientist who can connect and convince – not because he preaches apocalypse in gory detail, but in simple, overwhelming terms. We need to be taught to believe by a true believer in a world where belief is the fatal, missing ingredient.

• Climate change
• Climate change
• Climate change scepticism
• Obama administration
• US politics
• United Nations
• Copenhagen climate change conference 2009

Pop star-turned-physicist Brian Cox speaks about his new TV series on the solar system

It's big space, isn't it?

It's 93 million miles to the Sun: that's a long way. It takes light eight minutes to do that. There are 100bn galaxies in the observable universe. If you take a 5p coin and hold it 75 feet away, the space in the sky it would obscure would hold 10,000 galaxies. It's mindblowing. I don't think anyone has a grasp of that other than to say: it's big.

You recently answered claims that experiments with the Large Hadron Collider at CERN in Geneva might swallow the planet by saying: "Anyone who thinks the LHC will destroy the world is a twat." Ever worry that you might have phrased that more delicately?

It's not a comment, it's a statement of fact, isn't it? It's factually accurate! It's been everywhere, that. If you're lucky you get one quote on your gravestone and that'll be mine. It's like with Bruce Forsyth: "Nice to see you, to see you nice." I gave a talk in Florida the other week, and I walked on stage and said that and everyone was like: "Wahey!"

Should scientists be similarly robust when it comes to the arguments raging around climate change?

You mean swear more? I don't know whether it's because I'm from Oldham but I believe in a straight-talking version of science. There's nothing mystical about it. We are too delicate with people who talk crap sometimes. But issues like climate change are difficult for scientists because they're not politicians and there's obviously a toxic confluence of agendas there.

Where does your field of expertise lie?

I work in an area called diffraction. It's interesting for lots of technical reasons.

What first inspired you?

I was born in March 1968 and my father says I watched the moon landings. I always knew I wanted to be an astronomer or someone who explored space or a physicist.

What about your career as a pop star?

I went to see Duran Duran with my sister in Leeds when I was about 15. The Seven and the Ragged Tiger tour. I thought: that looks brilliant, so I learned to play keyboards. I actually met Nick Rhodes recently… he just laughed. But it panned out perfectly.Joined my first band when I was 18, made a couple of albums, toured with Europe, supported Jimmy Page. Left that band and joined D:Ream. '97 was the last thing I did – the election.

You played "Things Can Only Get Better" at the Royal Festival Hall the night Labour won. What was that like?

The song had gone back into the charts so we did Top of the Pops that morning. Then we went to a hotel which Labour had got us, overlooking the Houses of Parliament. Sat there, watched all those classic moments. Portillo getting voted out! Then they rang and said: "We've won", so we went and played. Robin Cook and everyone dancing…

You met Tony Blair at the time. Did he strike you as being all right?

Yeah. He still does. I bumped into him last year in Oxford and we had a brief chat. Blair's government was good for science. Funding is having a blip now. It's odd because it's such a small amount of money [we're talking about].

You're called "the rock star physicist". Do colleagues give you funny looks?

Careers don't tend to be long in rock, and I left to do physics at the right time. My colleagues know I've been in bands, and I don't just make TV programmes – I do try and use that platform to have arguments about science funding and so on, so I don't think there's much resentment. There can be, and it's reasonable, because if you're an academic and have a lot of admin to do… well, I've got out of that a bit. But if I'm off in Hawaii filming for the BBC, it doesn't look great.

In the first episode of your new TV series, we see you flicking through a book you had as a child called The Race Into Space. Does today's world live up to the vision of the future you enjoyed then?

That's a disappointing book when you look at it now! It says we were going to be on Mars by 1983. I met the head of exobiology at one of the big Nasa research institutes who knew the rocket pioneer Wernher von Braun from back in the early 60s. He told me they had a plan to go to Mars with the Saturn V rockets. If the programme hadn't been cancelled in the late 70s, they could have done it.

Historically, we've often thought we're getting close to cracking the secrets of the universe. Are we?

I honestly think the wheels are coming off our picture of the way the universe works at the moment. We don't know what 96% of the universe is made of – that tells us that we don't understand something fundamental. It reminds me of the start of the 20th century when quantum mechanics and relativity were about to appear.

We wouldn't expect a dog to understand the mysteries of the universe, so why should we imagine that we can?

It's an open question, whether it's too complicated. All you can do is point back to history to note that we've been successful on this reductionist journey up to now. But there's no reason…

Have you ever believed in God?

No! I was sent to Sunday school for a few weeks but I didn't like getting up on Sunday mornings. But some of my friends are religious. I don't have a strong view on religion, other than illogical religion. Young earth creationism, for example: bollocks.

You went to Alaska for your new series. What would you have said to Sarah Palin if you'd met her in a bar?

I would have started by asking: "Why do you think the Earth is only 6,000 years old?" I would have tried to convert her…

Interview by Caspar Llewellyn Smith

• Astronomy
• Physics
• Television