Page last updated at 00:33 GMT, Thursday, 27 August 2009 01:33 UK

'Artificial trees' to cut carbon

By Judith Burns Science and environment reporter, BBC News

Artificial trees could be used in areas where carbon emissions are high

Engineers say a forest of 100,000 "artificial trees" could be deployed within 10 to 20 years to help soak up the world's carbon emissions.

The trees are among three geo-engineering ideas highlighted as practical in a new report.

The authors from the Institution of Mechanical Engineers say that without geo-engineering it will be impossible to avoid dangerous climate change.

The report includes a 100-year roadmap to "decarbonise" the global economy.

No silver bullet

Launching the report, lead author Dr Tim Fox said geo-engineering should not be viewed as a "silver bullet" that could combat climate change in isolation.

He told BBC News it should be used in conjunction with efforts to reduce carbon emissions and to adapt to the effects of climate change.

Many climate scientists calculate that the world has only a few decades to reduce emissions before there is so much carbon dioxide in the atmosphere that a dangerous rise in global temperature is inevitable.

FROM THE TODAY PROGRAMME More from Today programme

The authors of this report say that geo-engineering of the type they propose should be used on a short-term basis to buy the world time, but in the long term it is vital to reduce emissions.

They define two types of geo-engineering. Nem Vaughan of University of East Anglia said: "The first category attempts to cool the planet by reflecting some of the sunlight away. The problem with this is that it just masks the problem."

"The other type of geo-engineering is to remove carbon dioxide from the atmosphere and store it."

Hundreds of options

The team studied hundreds of different options but have put forward just three as being practical and feasible using current technology.

A key factor in choosing the three was that they should be low-carbon technologies rather than adding to the problem.

Dr Fox told BBC News: "Artificial trees are already at the prototype stage and are very advanced in their design in terms of their automation and in the components that would be used.

"They could, within a relatively short duration, be moved forward into mass production and deployment."

The trees would work on the principle of capturing carbon dioxide from the air through a filter.

The CO2 would then be removed from the filter and stored. The report calls for the technology to be developed in conjunction with carbon storage infrastructure.

The captured carbon dioxide could be stored in empty north sea oil wells

Dr Fox said the prototype artificial tree was about the same size as a shipping container and could remove thousands of times more carbon dioxide from the atmosphere than an equivalent sized real tree.

Another of the team's preferred methods of capturing carbon is to install what they term "algae based photobioreactors" on buildings. These would be transparent containers containing algae which would remove carbon dioxide from the air during photosynthesis.

Algae units could be designed into new buildings or retrofitted to old ones

The third option focuses on the reduction of incoming solar radiation by reflecting sunlight back into space. The report says the simplest way of doing this is for buildings to have reflective roofs.

The authors stress that all of these options will require more research and have called for the UK government to invest 10 million pounds in analysis of the effectiveness, risks and costs of geo-engineering.

Dr Fox said: "We very much believe that the practical geo-engineering that we are proposing should be implemented and could be very much part of our landscape within the next 10 to 20 years."

Page last updated at 01:15 GMT, Friday, 4 September 2009 02:15 UK

Pupils receiving help 'do worse'

There are more than 180,000 teaching assistants in England's schools

Pupils who receive help from teaching assistants make less progress than classmates of similar ability, a government-funded study suggests.

The Institute of Education assessed the impact of the huge expansion in support staff in England and Wales since 2005 by studying 153 schools.

It said such staff tended to look after the pupils most in need, reducing their contact with the qualified teacher.

The government said teacher workloads and class behaviour had improved.

The expansion of the school support workforce, which began in 2003, was also intended to raise quality, giving extra support to children with special educational needs.

The more time pupils had with support staff the less time they had with the teacher Professor Peter Blatchford

The Deployment and Impact of Support Staff (DISS) project surveyed 20,000 teachers and analysed the help received by more than 8,000 pupils in 153 schools in 2005-6.

The researchers were so surprised by the results of their study, that they repeated it for 2007-8 and came to the same conclusion.

Lead researcher Professor Peter Blatchford said the results could not be explained by the lower attainment, special educational needs, family backgrounds and behavioural problems of those pupils who had help from teaching assistants as those factors had been accounted for.

He added: "This is not something that we should blame on teaching assistants - we are not saying they are a bad influence.

"It seems to be about the way in which they are deployed and the way in which they are managed.

"The main explanation seems to be that support staff tend to look after the children in most need. They can then become rather separate from the main curriculum.

"The more time pupils had with support staff, the less time they had with the teacher."

'Counter-intuitive'

Support staff tend to have less training and a lower level of education than teachers.

About two-thirds of the support staff in this study had not been educated beyond GCSE level.

A spokesman for the Department for Children, Schools and Families, which funded the study along with the Welsh Assembly, said support staff were the backbone of the teaching workforce.

"There is clear evidence that there is a positive effect on pupil's progress where teaching assistants are trained and effectively trained to deliver specific support programmes, alongside well-planned lessons - as this research acknowledges.

"And the DISS study found that 14-year-olds who worked closely with teaching assistants were less distracted... followed instructions, were more independent, confident, motivated and likely to complete work."

He added that the research made no allowance for teaching assistants' experience, training or qualifications nor whether the school was high- or low-performing, the extent it had been remodelled or whether the teacher or teaching assistant were teaching as a team or separately.

Head of education at the public service union Unison Christina McAnea said: "Unison has been calling for better pay, training and more paid time for teaching assistants to do their jobs, for many years.

"Teaching assistants are not substitutes for teachers, but what they can do, given the right training and support, is help children with special needs to get the most out of school."

The findings of the study are being presented at the British Educational Research Association conference in Manchester on Friday.

Page last updated at 13:29 GMT, Friday, 4 September 2009 14:29 UK

Girls 'born with fear of spiders'

Women's fear of spiders has now been linked to the behavioural traits of our hunter-gatherer ancestors

A new study in the US suggests that women have a genetic aversion to dangerous animals, such as spiders.

The research, published in the New Scientist, says women are born with character traits that were ingrained in our hunter-gatherer ancestors.

As child protectors, they have to shun animals that threaten them or their young off-spring, researchers said.

Previous research suggested women were actually up to four times more likely to be afraid of creatures like spiders.

The new research was headed up by developmental psychologist, Dr David Rakison, from Carnegie Mellon University in Pittsburgh, 10 baby girls, and 10 baby boys were subjected to a number of pictures of spiders to gauge their reactions.

First the babies were shown a picture of a spider with a fearful human face, followed by images of a spider paired with a happy face - alongside an image of a flower twinned with a fearful face.

The results showed that the girls - some as young as 11 months old - looked longer at the picture of the happy face with a spider than the boys, who looked at both images for an equal time.

The researchers concluded that the young girls were confused as to why someone would be happy to be twinned with a spider, and were quick to associate pictures of arachnids with fear.

The boys, it seems, remained totally indifferent emotionally.

'Ancestral behaviour'

Mr Rakison attributes this genetic predisposition to behavioural traits inherent in our hunter-gatherer ancestors.

Men, he purports, were the greater natural risk takers, the ones who took greater risks were more successful when going out to hunt for food.

With women, in their role as natural child protectors, it made sense for them to be more cautious of animals such as snakes or spiders, Mr Rakison adds.

By contrast, the research concludes that modern phobias such as the fear of hospitals - or that of flying - show no differences between the sexes.

Previous research has shown that almost 6% of people have a phobia of snakes, with nearly 4% scared of spiders.

However, of that percentage, four times are likely to be women than men.