the-BA : Science News Digest - 15 December 2007

Sea ice (image copyright: istockphoto.com)

In the science news this week: a deal is reached at the UN climate change conference but there are dramatic predictions for Arctic sea ice and coral reefs. Plus, magnetic ropes that connect the Earth to the Sun, video footage of the Mickey Mouse of the desert and how subliminal scents influence us…

Scientists at the American Geophysical Union (AGU) Fall Meeting presented dramatic forecasts for the disappearance of Arctic sea ice, reported BBC News. Data from their most recent modelling studies suggests that northern polar waters could be ice-free during summer within just five to six years and, since their projections used data sets from 1979 to 2004 and therefore didn’t incorporate data from the last two minima of ice cover which occurred this year and in 2005, they think that even their projection may be too conservative.

Other research teams have variously predicted that the Arctic will be ice-free any time ranging from about 2040 to 2100. However, Professor Wieslaw Maslowski's group from the Naval Postgraduate School in Moterery, California, which includes co-workers at NASA and the Institute of Oceanology, Polish Academy of Sciences (PAS), believe key melting processes have been seriously underestimated within these models.

‘My claim is that the global climate models underestimate the amount of heat delivered to the sea ice by oceanic advection,’ Professor Maslowski said. ‘The reason is that their low spatial resolution actually limits them from seeing important detailed factors. We use a high-resolution regional model for the Arctic Ocean and sea ice forced with realistic atmospheric data. This way, we get much more realistic forcing, from above by the atmosphere and from the bottom by the ocean.’
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A number of other stories were reported from the AGU meeting in San Francisco, including the significant discovery on the surface of Mars of deposits suggestive of past environments ideal for microbial life (reported by BBC News, but also mentioned in the Science News Digest back in May), and evidence from tusks and skulls that mammoths and other large animals were hit by meteorite debris some 35,000 years ago (reported by the Telegraph).
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Other scientists issued the stark warning that coral reefs are in danger of being killed off as a result of rising levels of carbon dioxide, reported the Guardian. Around a third of the gas produced by human activity is absorbed by oceans. While this limits its accumulation in the atmosphere, and hence the greenhouse effect, it dissolves in sea water to form carbonic acid. Carbonate minerals dissolve in this acidic environment and aragonite, which corals and other marine organisms used to grow their skeletons, is particularly susceptible. Without this mineral, corals are unable to grow or repair themselves.

Computer simulations of three scenarios based on emission predictions by the UN’s Intergovernmental Panel on Climate Change indicated that even if carbon dioxide levels were limited to between 450 and 500ppm (conditions predicted to increase global temperatures by two degrees Celcius) only very hardy corals would survive, with a knock-on effect for the creatures that rely on them. The study, published in the journal Science, indicated that the majority of reefs would die off if levels rose above 500ppm.
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Meanwhile, after days of heated negotiations, a deal was reached at the UN climate change talks in Bali. The final agreed text acknowledges that ‘deep cuts in global emissions will be required to achieve the ultimate objective’ of avoiding dangerous climate change but omits mention of specific emissions targets – the inclusion of binding targets were blocked by the US, Canada and Japan. Other sticking points related to commitments from developing countries.

Nations will now be working to agree a successor to the Kyoto Protocol according to parameters and aims laid down in the ‘Bali roadmap’, with negotiations to be finalised by the 2009 UN climate conference in Copenhagen.
(Read more about the conference and negotiated outcomes at BBC News)
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The Independent reported that a fleet of NASA satellites that have been monitoring the Northern Lights have found evidence of enormous magnetic ‘ropes’ that can form and unravel in the space of just a few minutes, and connect the Earth’s upper atmosphere directly to the Sun.

‘We believe that solar wind particles flow in along these ropes, providing energy for geomagnetic storms and auroras,’ said Dr David Sibeck, a NASA scientist from the Goddard Space Flight Centre in Maryland.

Spacecraft have detected the invisible ropes before, but the five Themis microsatellites enabled scientists to visualise their 3D structure – a twisted bundle of magnetic fields.
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According to US scientists, humans have evolved more quickly in the past 5,000 years than at any other time since the split with the ancestors of modern chimpanzees six million years ago.

Study leader, anthropologist Dr John Hawks, said: ‘The widespread assumption that human evolution has slowed down because it’s easier to live and we’ve conquered nature is absolutely not true. We didn’t conquer nature, we changed it in ways that created new selection pressures on us.’

The Guardian reported that analysis of genetic markers in 270 people from four groups (Han Chinese, Japanese, Africa’s Yoruba and northern European) using the international haplotype map of the human genome revealed that at least seven per cent of human genes have undergone recent evolution. Changes include the spread of a lactose-tolerance gene among Europeans, of partial resistance to malaria among some African populations, and of lighter skin and blue eyes in northern Europeans.
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In another study, scientists discovered that the reason that women don’t topple over when pregnant is that female spines have evolved to balance the foetal load in front of their hip joints and that mothers-to-be tilt backwards as they walk. Without this adaptation, where the curve of the lower back extends across more vertebrae which are also larger and angled differently to reinforce them, pregnancy would be much more painful, with a greater burden on back muscles. This could have put our ancestors at greater risk by limiting foraging capacity and the ability to evade predators. Neither chimpanzees nor men have these modifications.

Researchers from Harvard and the University of Texas studied 19 pregnant women between the ages of 20 and 40. They found that the women leaned backwards when standing naturally and that the curvature of their lower spine increased by as much as 60 per cent towards the end of their pregnancy, enabling them to maintain a stable centre of gravity above the hips. The researchers believe that this ‘spinal tip’ first appeared in the early human ancestor Australopithecus, at least two million years ago, reports the Telegraph.
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A scientific expedition to the Gobi desert in Mongolia has filmed the long-eared jerboa in its natural habitat for the first time, as part of a conservation effort. The creature has been dubbed ‘the Mickey Mouse of the desert’ thanks to its bizarre and rather comic appearance. It has enormous ears that are 35 per cent longer than its head, thought to help it pinpoint and catch insects in the dark. The animal jumps around on two legs – moving more like a kangaroo than a mouse – presumably helping it evade predators.

The Zoological Society of London (ZSL) identified it as one of the 100 most evolutionarily distinct and endangered mammals in the world earlier this year, and it was selected as one of their ten conservation priorities under the Edge (Evolutionarily Distinct and Globally Endangered) project. Zoologists were keen to get video footage of the little-understood animal in the wild, to increase their knowledge about its needs and habits.

‘It’s an extraordinary animal that looks as if it’s been designed by committee - kangaroo legs, snowshoe feet, huge ears and a pig’s nose,’ said expedition leader Dr Jonathon Baille. ‘It represents millions of years of evolutionary history and while it looks like a small rodent it’s very, very distinct. There’s no other animal of its type.’
(See video footage of the long-eared jerboa on the Times’ website)
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Other news in brief:

BBC News reported that leading physicists were dismayed at an £80 million research funding shortfall announced by the Science and Technology Facilities Council, after major infrastructure projects incurred higher running costs than anticipated. Potential cutbacks could impact on the council’s entire research programme, including particle physics, astronomy and laser physics.
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The genetic code of the moss Physcomitrella patens has been deciphered. It is the first non-flowering plant to be sequenced. Since mosses are able to survive severe dehydration and re-grow when water is available, information about the plant’s genetic sequence could help create drought-resistant crops. The information will also provide insights into how plants evolved from water-based algae to thrive in a terrestrial environment.
(The Telegraph)
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Scientists believe that microbes could help access up to ten per cent more energy out of oil reserves thanks to their ability to extract methane from reserves where the oil has degraded into a thick tar. Currently, polluting processes such as injecting steam are used to loosen the tar-like bitumen so that it can be pumped to the surface. In comparison to bitumen, methane is a much cleaner fuel, emitting much less carbon dioxide. Understanding the process by which microbes breaks the tar down to produce methane raises the possibility of being able to stimulate and accelerate it and researcher Professor Steve Larter anticipates field tests by 2009.
(The Telegraph)
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A 27-year-old ‘mathlete’ broke his own world speed record for calculating the 13th root of a randomly generated 200-digit number. Alexis Lemaire, a French student who is working on an artificial intelligence PhD, took just 70.2 seconds to reach the 16-digit answer. He wouldn’t reveal his method but said ‘I am doing something like artificial intelligence in reverse, because I am imitating a computer.’
(The Telegraph)
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And finally…

American scientists have conducted a study that suggests whether or not we like somebody can be influenced by subliminal scents, reported the Telegraph.

Dr Wen Li and colleagues at Northwestern University, Chicago, asked 31 people to sniff bottles with three different odours: lemon (good), sweat (foul) and ethereal (neutral), that were present at such low levels most people weren’t aware of them. The volunteers were then asked to rate a human face with a neutral expression on a scale ranging from extremely likeable to extremely unlikeable.

When lemon scent was present the face was judged as more likeable, whereas sweat resulted in a less favourable impression. However, it was only when the smell wasn’t noticed that the judgements were biased – the few people who could detect the trace smell didn’t show a bias, and Dr Li says they ‘were able to discount that sensory information and just evaluate the faces’.

So it seems that if you want to make a good impression on someone this holiday season, you’d do well to apply any perfume or aftershave sparingly.

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