Using GPS, field measurements, radar data and seismological records, a team of international researchers investigated the parameters and reconstructed the events of two massive earthquakes, measuring 8.4 and 7.9 on the Richter scale, which occurred in the Mentawai area in 2007.

Previous models of how earthquakes work had suggested that the same fault would rupture in the same way and at regular, predictable time intervals. But the researchers found that the 2007 quakes ruptured only a fraction of the area affected by the giant 1833 earthquake, indicating that a tectonic plate boundary can rupture in different patterns depending on local differences in stress.

“What we see here is that the 2007 earthquake had at least a very big overlap with the 1833 earthquake, but it was very much smaller; in other words, it was an entirely different earthquake,” says , a geophysicist at the University of Ulster, UK.

Fault at fault

The GPS data enabled the researchers to create a map of the fault zone, showing which parts were locked tight and which parts were slipping freely. This allowed them to estimate where the most strain has built up, and where the next big rupture is most likely to occur.

The results suggested that the 2007 events released only a quarter of the energy that had accumulated since 1833, leaving enough pent-up energy to trigger another giant earthquake at any time. This event could be anything between magnitude 8.2 and over 9, says McCloskey.

The earthquake that led to the devastating Asian tsunami of 2004 occurred in a different part of the same fault and measured between 9.0 and 9.3. The 2004 event is thought to have increased the strain on the Mentawai region, making an earthquake there even more likely.

The potential devastation that such an earthquake could cause is horrifying, says McCloskey.

30-minute warning

“There’s a city called Padang, with 840,000 people, facing right into the place where we know the fault hasn’t broken since 1797,” he says. “It’s more stressed now than it was in 1797, so it could be quite soon.”

Since the 2004 event, a tsunami warning system has been put in place to prepare the region for further quakes.

But, according to McCloskey, it will be next to useless for this earthquake, since it will occur so close to inhabited areas that there will be no time for advance warning. “The ground’s going to shake so hard during this earthquake that you don’t need a tsunami warning system,” he says.

When the next big earthquake strikes, says McCloskey, people living nearby will have less than 30 minutes to get to high ground.

Journal reference: , (in press)

Not only are 1980s garish clothes and synthpop music back in fashion, but it seems the era’s environmental problems are also returning to haunt us.

One of the first empirical studies to look at how global warming is affecting ecosystem health has found that the wet winters of recent years have hampered the recovery of streams from damage caused by acid rain decades ago.

We are going to find more and more cases where climate change exacerbates other forms of environmental degradation, says Peter Kareiva of US environment charity .

“Previous achievements in environmental sustainability can be overturned when climate disruption piles on,” he says. “There is a good chance that the climate’s interactions with other environmental stresses may end up being the greatest risk we face, as opposed to the direct impacts of global warming.”

Acid rain was one of the defining environmental issues of the 1980s, causing acid deposition in streams and rivers, making them uninhabitable for many species. But with increasing efforts to clean up sources of acid rain, acidity levels in the water had been steadily dropping.

Wet, wet, wet

and colleagues at Cardiff University in the UK have monitored the temperature and acidity levels of 14 Welsh streams – as well as the insects living there – for the past 25 years.

With the reduction in acid rain, they expected to see many insect species recolonising the streams. But their findings revealed that the aquatic ecosystems hadn’t recovered as well as expected.

The researchers blame the recent increase in rainfall during the winter months. According to Ormerod, up to 40% of the last 25 years-worth of improvements have been cancelled out as a result of the recent weather changes.

“It looks as though wetter winter conditions are a problem, and given that the prediction is for rainfall volumes to go up by about 30%, there is this potential for knocking out recovery from things like acidification,” he says.

Dead or alive

Increased rainfall reduces the buffering capacity of river systems by diluting base ions in the water and increasing acid ion input by increasing run-off from soils. “This is sufficient to push things in the acid direction again,” Ormerod says. “So even though we’ve fixed an awful lot of the acid deposition problem, we still get the kind of acid episodes that are knocking out sensitive organisms.”

Other environmental pollutants, such as nitrates are also affected by weather changes. In drought conditions, the flow volumes of rivers go down, and nitrates and other pollutants being discharged into rivers can have a greater ecological impact.

The spread of invasive species, sediment mobilisation, and the management of land use could all potentially be affected by climate change, says Ormerod. “Our work really emphasises that those predictions are being upheld,” he says.

Experts told ��è����Ƶ that they are concerned that Ormerod’s study might be just one example of a wider phenomenon where recent changes to the climate are exacerbating other environmental problems.

Crowded house

Tony Janetos, of the in Baltimore says there are many ways in which climate change can amplify existing environmental stress. For example, the rise in sea levels and the consequent rise in storm surges make the challenge of coastal erosion and property damage much more costly.

Also, “the expected increases in drought frequency in the western US make existing water management challenges more severe, and are already leading to an increase of wildfires and pest infestations in the regions forests – both of which have long-term implications for ecosystem integrity and economic impacts.”

Ecologist of the University of Colorado says the warmer temperatures, combined with a longer growing season, elevated carbon dioxide concentrations, and higher inorganic nitrogen inputs are boosting the success of invasive species.

“This has expressed itself with the emergence of annual plants as significant cover components in our grasslands, something not seen in the past,” he says. “Our native perennial species have not, to date, been able to keep up with these changes.”

Seastedt says we need to be proactive in establishing desirable species in the appropriate habitats. “Just treating past problems is no longer sufficient,” he says.

Journal reference:

, a new book by businessman and climate-change commentator , says climate change can be overcome if we adopt the following energy sources and technologies:

1. Wind power

Despite a reputation for being unreliable, wind power has the potential to provide more than 30% of the world’s electricity. The wind does not blow constantly, of course, so we will need to develop better ways of storing the energy we generate with it. And rather than being used purely locally, wind energy will have to be distributed between different states and countries.

2. Solar energy

The sun provides more than enough energy to power the world many times over – we just need to come up with an effective way of capturing this energy. Current solar panels are relatively inefficient, but increasing investment in solar cells is producing better models which capture more energy and cost less to produce.

3. Power from the oceans

Tides, waves and currents possess huge potential for low-carbon energy generation, but efforts to harness them have been hampered by the difficulty of designing devices that can tolerate harsh oceanic conditions. This year, however, power-generating buoys that harness wave energy 50 metres underwater were put to the test in the UK, and the world’s first commercial-scale tidal turbine delivered electricity to the UK national grid.

4. Combined heat and power

Waste heat accounts for about 40% of the energy produced by power stations. One way to avoid this is to bring the power station into the home, by installing domestic microgenerators. These miniature power plants are almost as efficient as huge generators and the heat they produce can be used to heat our homes and water.

5. Super-efficient homes

Instead of building new houses that are “zero carbon”, a better – and cheaper – way to reduce greenhouse gas emissions from domestic housing is to eco-renovate existing buildings. Germany is leading the way with the , which aims to reduce emissions by 80-90% through measures such as insulating walls and windows and using improved ventilation methods that don’t lose heat.

6. Electric cars

Electric cars have a bad reputation when it comes to style and speed, two factors that matter to car enthusiasts. But electric sports cars like the Tesla Roadster can give petrol-powered models a run for their money. Though they’re not cheap at the moment, prices are likely to come down as batteries improve.

And with running costs as little as 5% those of diesel models, electric cars will soon start to look like a more viable option. Recent research has even suggested that electric cars could act as energy stores for the power grid when not being driven.

7. Second-generation biofuels

Making fuel from food crops is now almost universally regarded as a bad idea, encouraging deforestation and potentially leading to food shortages. But the next generation of biofuels made from agricultural waste shows real promise. Using new cellulose-cracking technologies, waste wood can be broken down into liquid fuel, and with US venture capitalists investing heavily in these technologies, it won’t be long until this idea becomes a reality. However, with the global appetite for fuel on the increase, careful management of cellulose production will be vital.

8. Carbon capture

With the growth of renewable energy sources failing to keep up with world demand for electricity, finding an effective way of capturing and storing the carbon dioxide produced by power stations is one of the most important challenges we face. Investment in carbon-capture technologies has been slow to pick up, but governments around the world are starting to understand the importance of funding this research, and promising new technologies are already emerging.

9. Biochar

With predictions of climate change getting increasingly urgent, we desperately need cheap, simple and fast ways of reducing greenhouse emissions. One idea is to sequester carbon as biochar, a charcoal made from burning agricultural waste in the absence of air. Biochar is exceptionally stable and can be stored underground for hundreds of years without releasing its carbon into the atmosphere – and it improves the fertility of the soil.

10. Biogas stoves

Deforestation is a complex issue, and it’s looking more and more likely that we will have to pay people to maintain forest lands. But until such a system is up and running, we will need to focus on technologies that reduce the need to cut down trees. One such technology is biogas stoves, powered by methane released from rotting organic waste, which would otherwise be released into the atmosphere. Leading the way is China, which is heavily promoting the use of biogas technologies.

Video: Antarctic species tallied up

A group of isolated Antarctic islands have proved to be unexpectedly rich in life. The first comprehensive biodiversity survey of the South Orkney Islands, near the tip of the Antarctic Peninsula, has revealed that they are home to more species of sea and land animals than the Galapagos.

See a gallery of South Orkney animals

The findings raise the issue of what sort of impact climate change – already hitting the Antarctic hard – will have on this rich biodiversity.

Researchers from the British Antarctic Survey and the University of Hamburg, Germany, carried out the survey using a combination of trawl nets, sampling as deep as 1500m, and scuba divers. The team found over 1200 species, a third of which were not thought to live in the region. They also identified five new species.

The majority of animals were found in the sea, with most living on the seabed.

These findings go against the traditional view that biodiversity declines away from the tropics and towards the polar regions, says lead researcher of the British Antarctic Survey.

“Our paper makes the point that if you go right the way across different animal groups rather than taking one specific animal group, which is what most biodiversity studies do, then you get a much better perspective of real biodiversity,” he says. “This is the first place in either polar region, not just the Antarctic, where we’ve actually got a biodiversity across all groups.”

Previous research has shown that Antarctic waters harbour a surprising diversity of plankton and larvae and that deep-sea life in the Southern Ocean is similarly rich. But the new study is the first to look at all animals on land as well as in the seas.

“As the sea gets warmer, then temperate species will move into Antarctica and Antarctic species will shift further south or into colder regions,” says Barnes. “The South Orkney Islands is the one place where we have a real possibility of detecting new things arriving and things leaving.”

, a marine ecologist at the University of Southampton, UK, agrees. “The starting point for any conservation strategy has got to be knowing what you’ve got to conserve,” he says, “and this study provides a very valuable baseline in that regard.”

While biodiversity in this region may not decrease as a result of the warming, says Barnes, it is likely that the changes in species composition will result in an overall loss in the Earth’s biodiversity.

“All that it will take is for a few things to alter,” says Barnes. “It is only a matter of time.”

Journal reference: Journal of Biogeography, DOI:

The world’s forests – and the billion people who depend on them – are facing devastation from climate change unless we “evolve” with the changing situation, according to a new report.

The (CIFOR) reviewed the scientific literature on the effects of climate change on forests and concluded that it will have a dramatic effect on forests, irrespective of the future rate of greenhouse-gas emissions.

See a gallery of images of the crisis facing the world’s forests

Within the next 100 years, tropical regions are likely to heat up at a faster rate than the global average. Rainfall and summer monsoons will increase in some areas, while annual rainfall will decrease in others; tropical cyclones may become more severe, and droughts, floods and wildfires are likely to be more common, (pdf format).

Unless immediate adaptive action is taken, says lead author of CIFOR, these changes will lead to a self-perpetuating cycle, where destruction of the forests leads to an increased amount of carbon in the atmosphere, which will in turn cause further climate change, and so on. The report identifies two categories of adaptation.

“The first is to buffer ecosystems against climate-related disturbances like improving fire management to reduce the risk of uncontrolled wildfires or the control of invasive species,” he says. “In plantations, we can select species that are better suited to coping with the predicted changes in climate.”

“The second would help forests to evolve towards new states better suited to the altered climate,” Locatelli says. “In this way we evolve with the changing climate rather than resist it.”

Efforts to deal with the problem tend to focus on reducing deforestation, but the report calls for more emphasis on urgent adaptation measures to help the forests and forest communities to cope with the inevitable changes. “In this way we evolve with the changing climate rather than resist it,” he says.

, a climate-change researcher at the University of Edinburgh, UK, agrees with the recommendations, but points out that mitigation is still key.

“Much more important than climate-change impacts, in terms of the next few decades, is human activity,” he says. “It’s deforestation and degradation – that’s what’s going to destroy these huge carbon sinks before climate change has a chance to get at them.”

Evidence that maternal stress might be implicated in schizophrenia susceptibility has been mounting, but until now no one knew which part of the pregnancy was important.

Medical records spanning the short but violent Arab-Israeli conflict of 1967 enabled of New York University School of Medicine and colleagues to pin down when the damage was done.

They analysed the medical records of over 88,000 people born in Jerusalem during the ’60s and ’70s. The researchers found that women whose mothers were in their second month of pregnancy during the war were 4.3 times more likely to develop schizophrenia later in life, and men 1.2 times more likely, than people born during more peaceful times. .

Vulnerable males

The second month of pregnancy seems to be the key period during which disruption of the brain’s development can lead to schizophrenia in later life.

As for why females seem more vulnerable, Malaspina speculates that more as a result of the stress, so never made it into the study in the first place. “Many studies have shown a change in the sex ratio of a population undergoing severe upheaval or stress, and that change is a loss of male fetuses,” she notes.

Pregnant women under pressure need not panic; the levels of stress required are equivalent to those experienced during a terrorist attack or a natural disaster. Malaspina told ��è����Ƶ that when the team looked separately at women who were subjected to direct shelling, they found a 30-fold increased risk of having offspring with schizophrenia, suggesting that the risk depends on the severity of stress the woman is subjected to.

“This is about very extreme levels of stress and should not be generalised to day-to-day living stresses.”

Journal reference: BMC Psychiatry

An increasingly inactive lifestyle is often blamed for the soaring obesity rates in the developed world, but few studies have measured whether lifestyle changes have decreased the amount of energy we burn.

To address this, of the University of Aberdeen, UK, and of Maastricht University in the Netherlands looked at the amount of energy used through physical activity over the past 25 years in 393 people from across the US and 366 from Maastricht.

In these subjects, energy expenditure has been measured since 1982 using a technique called the “doubly labelled water method”, which measures the throughput of water labelled with isotopes of hydrogen and oxygen. By comparing the daily energy expenditure in the early 1980s with current data, the researchers showed that there has been no significant decline in the energy the people studied burned through physical activity.

The obesity epidemic had already started by 1982, but Speakman argues that people have always been fairly inactive during the evenings, and that although activities such as watching TV and playing computer games might be relatively new, they have not affected overall energy expenditure.

“Prior to widespread TV ownership we probably spent this time listening to the radio, before that reading, and before electrical lights were discovered we would have been asleep,” he says.

If we are not less active, then we must be eating more food, suggesting that trying to increase our energy expenditure through physical activity may not be the best way of tackling obesity.

“If we want to reverse the obesity epidemic it would be much better to focus on trying to decrease caloric intake,” says Speakman.

But of Monash University in Victoria, Australia, warns that a complex problem like obesity requires a complex solution. “Addressing the current obesity epidemic requires an integrated approach over and above modifying energy intake,” he says.

Journal reference: International Journal of Obesity (DOI:10.1038/ijo.2008.74)

Previous work has suggested that genes influencing sexual orientation in men also make women more likely to reproduce. and colleagues at the University of Padua, Italy, showed that the female relatives of homosexual men tend to have more children, suggesting that genes on the X chromosome are responsible. Now the team have shown that the same is true for bisexuality.

“It helps to answer a perplexing question – how can there be ‘gay genes’ given that gay sex doesn’t lead to procreation?” says of the National Institutes of Health in Bethesda, Maryland, who was not involved in the work. “The answer is remarkably simple: the same gene that causes men to like men also causes women to like men, and as a result to have more children.”

Sexual attraction

The researchers asked 239 men to fill out questionnaires about their families and their past sexual experiences. On the basis of their answers, the men were classified as heterosexual, bisexual or homosexual. The results showed that the maternal aunts, grandmothers and mothers of both bisexual men and homosexuals had more children than those of heterosexual men.

Camperio Ciani emphasises that, rather than being a “gay gene”, this unidentified genetic factor is likely to promote sexual attraction to men in both men and women. This would influence a woman’s attitude rather than actually increasing her fertility, making her likely to have more children.

, a neuroscientist and writer based in West Hollywood, California, describes this as a sort of “hyper-heterosexuality” and explains how it would help to ensure that homosexual behaviour was passed on through the generations. “The positive effect of an X-linked gene on female fecundity tends to outweigh the negative effect of the gene on male fecundity.”

According to Camperio Ciani and colleagues, the same genetic factor appearing to be present in both bisexual and homosexual men provides further support for the idea that sexuality is determined by a complex mix of genes and experience.

“We understand that the genetic component has to interact with something to produce different phenotypes,” says Camperio Ciani.

“Genetics is not determining the sexual orientation, it’s only influencing it.”

Journal reference: The Journal of Sexual Medicine (DOI:10.1111/j.1743-6109.2008.00944.x)

“We don’t know whether or not there’s an effect in people,” says of Rutgers University, Piscataway, New Jersey, who carried out the study.

Conney and colleagues discovered, by accident, that moisturisers increase the carcinogenic effects of UV damage while they were investigating how caffeine levels affected the development of skin cancer. Apparently inert moisturising cream was used as a vehicle for caffeine, but the team found it had unexpected tumorigenic activity.

The team tested four common moisturisers, Dermabase, Dermovan, Eucerin and Vanicream, on hairless mice that had previously been exposed to UV irradiation twice a week for 20 weeks. This put them at high risk of developing non-lethal skin cancer later on.

Bigger, faster tumours

Although UV-exposed mice that were not treated with moisturiser did develop skin cancer, those who were treated with moisturisers developed more tumours of a larger size and at a higher rate than the controls.

“We tested a total of four moisturising creams, and all four of them had tumorigenic activity,” says Conney. The resultant skin cancers were basal cell and squamous cell carcinomas, and not the more lethal melanomas.

The ingredients responsible for this effect remain a mystery, but two prime suspects are mineral oil, which has been shown to be tumorigenic in animal models, and sodium lauryl sulphate, a known irritant.

The researchers tested a cream they made themselves without these ingredients. Their own product – for which the group have filed a patent application – did not cause a significant increase in tumour formation. However, some of the creams that did show tumorigenic activity did not contain the suspect compounds.

“The products they tested had multiple ingredients with no consistent overlap, so it is hard to identify which agents – if any – could be implicated,” says David Leffell of Yale School of Medicine, who was not part of the study.

Mice aren’t men

Leffell also highlights important differences between mice and men.

The skin of mice is much thinner, so we cannot conclude that the same effects would be noted in humans. What’s more, there are several agents that are known to cause skin cancer in mice but do not have the same effect in people.

“Moisturizers are used more in women than in men, yet we do not see a relative increase in skin cancer in women compared with men,” he adds.

, of the European Institute of Oncology, in Milan, Italy, agrees, but points out that the study still raises an important point:

“There is no evidence of danger to humans in this study, but the message to scientists is clear. Be careful in assuming that seemingly inert creams will have no interference with animal experiments.”

Journal reference: (DOI: 10.1038/jid.2008.241)

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