Stripping Down Science (21 page)

But why? The reason became apparent when the team graphically reconstructed the eye movements made by both groups when they looked at the images. It was clear that while the western Caucasians tended to survey the whole face – and apply roughly equal weight to most regions – the East Asians strongly biased their observations in favour of the eye region of each face. As a result, the Asian participants had a harder time distinguishing emotions in which the eyes look similar but the set of the mouth differs. For instance, faces showing fear or surprise both have big, wide open eyes, but the mouths are very different. ‘It would be difficult to distinguish between the two … if you didn't look at the mouth,' says Rachael Jack.

More intriguing is the fact that the evidence for this dramatic finding has already been staring us all in the face on the internet for many years in the form of the ‘emoticons' users add to the things they write online to convey their emotions. Westerners tend to employ symbols that use the mouth to convey emotional states such as :) to imply happiness, or :( for sad. But look at the blog post of an easterner and you'll find the eyes
doing the work instead, as in ^.^ for happy and ;.; for sad.

The big question, though, is how this difference has arisen in the first place and why, which is what the researchers are now investigating. Convinced that the effect is cultural rather than inherited, they are mapping out how emotions are manifested in Asian faces, as well as trying to find out what happens to children born in the west to Chinese parents. Can they switch expression-reading strategies to suit their immediate surroundings?

If the cause is a cultural one, a likely explanation for the observed east–west divide is that some Asian cultures consider overt displays of emotions to be impolite. For this reason, these people may have learned to focus on more subtle cues arising from around the eyes rather than relying on mouth movements to do the talking.

In attempting to understand how the atmosphere circulates around the earth, and particularly how pollutants are carried aloft, researchers recently realised that there was a monsoon-sized hole in their atmospheric argument.

Scientists divide up the earth's atmosphere into a number of different layers. Between the ground and a height of up to 15 kilometres is the so-called troposphere, which is thickest at the equator and thinnest at the poles. It's created by heat from the earth's surface causing rising currents of warm air that trigger winds, rain and other weather phenomena. Above the troposphere is a layer called the stratosphere, which extends up to a height of about 51 kilometres above the planet's surface and also contains the ozone layer, which shields us from the sun's ultraviolet rays. Between the troposphere and stratosphere is a layer called the tropopause, which is the point at which air from the planet's surface stops rising
and becomes almost completely dry.

Researchers have found that the air in the troposphere and the air in the stratosphere largely remain separated from each other and only able to mix in appreciable amounts over the tropics. Canadian climatologist Alan Brewer and Oxford physicist Gordon Dobson first identified this phenomenon over 60 years ago and it is now known as the Brewer-Dobson circulation in their honour. Consequently, scientists thought that pollutants present in the troposphere (arising from the earth's surface) would only be able to enter the stratosphere if they first made their way to the tropics in order to join air rising in the Brewer-Dobson circulation. However, en route to the tropics, many pollutants are soaked up by the sea long before they can be carried aloft, which helps to keep the contamination out of the stratosphere.

But now scientists have discovered that the Asian monsoon – an annual storm system that occurs when warm, moist air from the Indian and Pacific Oceans is drawn in over Asia by the temperature difference between the land and the sea – might be providing an alternative portal to the upper atmosphere, ferrying with it water,
carbon particles, oxides of sulphur and nitrogen and also ozone-damaging halogen compounds produced by Asia's burgeoning heavy industries.

This atmospheric body blow was revealed by US researcher William Randel, based in Boulder, Colorado.
⁷¹
He used a satellite-based system called ACE-FTS (atmospheric chemistry experiment Fourier transform spectrophotometer) to track the levels of the gas hydrogen cyanide around the globe. Scary as it sounds, hydrogen cyanide is produced quite normally when plant-based material is burned, for instance when forests are cleared for agriculture. Usually, it is quickly mopped up by the ocean, so the levels are kept low. But the satellite images told a different story: spreading out across the stratosphere above the top of the monsoon was a very high concentration of the gas, indicating that the monsoon was sufficiently powerful to breach the tropopause and create a superhighway skyward for all kinds of atmospheric nasties.

‘The monsoon is one of the most powerful atmospheric circulation systems on the planet, and it happens to form right over a heavily polluted
region,' says Randel. ‘As a result, it provides a pathway for transporting pollutants up into the stratosphere.' So in the monsoon, Asia effectively has its own atmospheric extractor hood directly overhead.

For the moment, researchers don't know what impacts this fast-track route to the stratosphere could be having, but they're worried because once they reach the stratosphere, the kinds of chemicals being carried aloft like this can continue to circulate around the globe for years. This suggests that the impact of Asian pollutants could increase significantly in the coming decades owing to intensifying industrialisation, especially in China. Another uncertainty is how climate change could impact on the power of the monsoon, which could accelerate all of these effects. Never underestimate the power of the wind, it seems – especially on Boxing Day …

FACT BOX

What else can the wind do?

Apart from providing Asia with an atmospheric equivalent of a giant vacuum cleaner to eject pollution skywards, scientists have also uncovered evidence recently that large storms might make the earth move too, by setting off certain types of earthquakes.

The phenomenon was discovered by Taiwanese researcher ChiChing Liu and two US scientists, Alan Linde and Selwyn Sacks.
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Between 2002 and 2007, they buried underground strain-sensing devices in eastern Taiwan and used them to follow how the earth's surface was deforming in this region over time. They were quite shaken to discover that these devices could actually pick up the arrival of the big seasonal tropical storms called typhoons, which occur predominantly in the second half of each year.

These storms are accompanied by very low
pressure, which usually causes the ground to swell, which is what the team could see on their subterranean strainmeters. But occasionally they would pick up the reverse effect – the ground appeared to have shrunk rather than stretched when a storm came.

In all, they detected 11 events like this, each of them associated with typhoons. The likelihood of this occurring by chance is less than one in a million and the only explanation, say the scientists, is that the typhoons are triggering ‘slow earthquakes', which are ground movements that occur over longer time scales – hours to days – than their normal vigorous counterparts, which tend to subside within seconds.

The storms unleash the slow quakes by increasing the stress across faults. This occurs because the arrival of a storm system causes the pressure to drop over the land surface, but to remain unchanged over the sea. This is because low air pressure occurring over the sea causes more water to move into that area to compensate, so the sea floor feels the same
amount of force. As a result, during a storm the stress across nearby faults can increase and if they are primed to move, a quake follows.

Paradoxically, this mechanism might actually help to protect Taiwan, where the Philippine Sea plate and the Eurasian plate are colliding. The plates are trying to move past one another at more than eight centimetres per year, so by periodically ‘unloading' the fault, these slow quakes can prevent a build-up of energy that would otherwise be unleashed suddenly with potentially catastrophic effects, as has occurred with devastating effect in Iran and Haiti recently.

The prevailing view about whether it's feasible to forecast the date of an earthquake is that you can't. The best we can do, scientists say, is to try to spot which faults – the locations where two or more tectonic plates touch – are storing up energy and trouble for the future, and then warn people locally, although when the fault will finally give way it's impossible to say. But now, new research suggests that this is something of a seismic myth, because toads, it turns out, appear to be the quake-equivalent of a caged canary – they can tell well in advance when they need to hop it!

All around the globe, geologists are doing the hi-tech equivalent of holding a glass to the wall to pick up on the inner murmurings of the earth in order to identify signature sounds that might herald the arrival of a forthcoming earthquake. At the same time, other scientists are scrutinising the planet's surface in excruciating detail from space, looking for subtle signs and deformations
in the lie of the land which might indicate that an upheaval is imminent. This is important because unearthing evidence that a quake may be about to happen is a major scientific priority. According to the United Nations, earthquakes cause an average of 78,000 deaths worldwide per year and have accounted for 60% of all natural disaster deaths since the year 2000.

As geologists are quick to stress, it's not actually earthquakes that usually kill people: collapsing buildings do. Therefore, knowing when one is due to happen in advance could make a life and death difference for those affected, because it would enable people to be safely evacuated beforehand. This would be especially helpful in developing countries, where the buildings are of generally poorer quality and usually aren't designed to be earthquake-resistant. That said, despite years of effort, and the fact that scientists now know where most of the likely trouble spots are, researchers aren't much closer to telling exactly where and when disaster will strike. It's quite surprising then to find that the humble toad seems to be able to tell what geologists can't – and presage a quake more than five days ahead.

Two scientists from the UK's Open University,
Rachel Grant and Tim Halliday,
⁷³
uncovered evidence of this extraordinary amphibian example of clairvoyance while monitoring mating toads around the San Ruffino lake in central Italy during the spring of 2009. Usually, toads converge on the lake in large numbers and time their matings to coincide with the full moon. They then remain in the vicinity for a month or two, until spawning is complete, before dispersing again.

But on 31 March 2009, when breeding had barely begun, the 90 or so animals that had gathered to mate all abruptly vanished. Six days later, the area was hit by a magnitude 6.3 earthquake. Some toads did return at the full moon shortly after to mate, but the majority remained absent for a further nine days until the last significant aftershocks had finally died away. Then their numbers climbed again. Eliminating other major factors, like the weather – which didn't change – the only explanation is that the toads somehow detected the impending earthquake five days ahead of its arrival.

Incredible as this sounds, the results resonate with other previous studies that indicate certain
species might be able to predict when a seismic shake-up is on the way. In China, scientists reported in the 1970s that fish, rodents, wolves and snakes had been behaving oddly up to two months before a major 7.8 Richter scale quake in Tanshang. There are also reports going back to the 1920s from Europe, Asia and the Americas describing strange behaviour in fish, rodents and some snakes up to a week or so prior to a quake.