Science stories of 2006

It's been a year of little leaps. Nothing Earth-shattering or, at least, nothing the world has noticed yet. Someone once remarked to me that the most important scientific result of the year just gone wouldn't be recognised until several years later, when its implications were much clearer. For what it's worth, here's what James and I thought were the most interesting and noteworthy science stories of 2006. Perhaps the low-key year is an unconscious repsonse to the Hwang scandal - the Korean scientist faked research and papers on cloning and was discovered at the end of last year.

It was also a year of warnings: a worsening biodiversity crisis, the Arctic ice cap predicted to be ice-free in summer by 2040 and UK chief scientific adviser David King making his starkest predictions yet on the effects of climate change. One piece of good news (possibly) on the last front: with British economist Nicholas Stern's report on the potential cost of climate change, will 2006 go down as the year the world work up to the problem?

It wasn't entirely quiet on the discovery front: the spectacular Stardust mission to bring comet dust back to earth; the Tiktaalik fossil (pictured) that gave biologists clues on how animals made it from water to land; and flowing water on Mars. Here's to more brilliance in 2007...


Fish out of water, polar ice, and leakage on Mars

Tiktaalik

A crocodile-like fossil called Tiktaalik roseae, found on Ellesmere Island, Canada, sent scientists wild with excitement. A missing link between fish and land animals, it showed how creatures first walked out of the water and on to dry land more than 375m years ago. Tiktaalik - the name means "a large, shallow-water fish" in the Inuit language - lived in the Devonian era lasting from 417m to 354m years ago, and had a skull, neck, and ribs similar to early limbed animals, known as tetrapods, as well as a more primitive jaw, fins, and scales akin to fish. It showed that the evolution of animals from living in water to living on land happened gradually, with fish first living in shallow water.

Arctic ice

Sir David King, the UK's chief scientific advisor, warned that, unless governments around the world took urgent action against climate change, global temperatures would rise by 3C, resulting in global famine and drought and threatening millions of lives. Cereal crop production could drop by between 20m and 400m tonnes, 400 million more people would be at risk of hunger, and 3 billion would be at extra risk of flooding and without access to freshwater supplies. This year, scientists calculated the Antarctic ice sheet is losing 36 cubic miles of ice every year. They also made the startling prediction that the Arctic ice cap will lose all of its summer sea ice by 2040, given the accelerating rate of melting observed in recent years.

Cellardyke swan

The dreaded avian flu, H5N1, turned up in a dead swan in Cellardyke, Fife. The virus seemed to remain confined to wild birds, however, and the potentially deadly flu caused no human casualties in the UK. It does not mark the end of H5N1, however. Scientists predict it will be back in the coming months and begin to spread around the world again as birds begin migration. For it to become deadly to humans, H5N1 needs to mutate so that it can transfer easily between people. So far this has not happened.

Stardust

Nasa's adventurous Stardust mission brought the dust of a comet back to Earth. The mission was full of firsts: the first time a probe had been flown so close to a comet; the first extraterrestrial use of the advanced aerogel material - a hi-tech mousse made of glass and air sometimes called "frozen smoke" - to trap the grains of dust; and the first successful sample return to Earth since the moon landings. The first results were published in December and showed that scientists would have to rewrite the textbooks on comet formation. Not only are these objects more than simply dirty snowballs, as had been previously thought, scientists found materials in them that suggest they could have kickstarted life on Earth.

Pluto

The underdog planet, smaller than the moon, was kicked out of the planetary club by the International Astronomical Union. The 2,500 scientists of the union decided on a definition of a planet as a body that orbits the sun, is so large that its own gravity makes it roughly spherical, and, crucially, also dominates its region of the solar system. Their decision will force a rewrite of science textbooks because the solar system is now a place with eight planets and three newly defined "dwarf planets" - a new category of object that includes Pluto. The category also includes an asteroid called Ceres and an object bigger than Pluto, initially called 2003 UB313 but later named officially as Eris.

Messing about in space

2006 was the year for doing weird, risky and just plain daft things in space. In February, an old Russian space suit filled with clothes was shoved out of the International Space Station. This was the cosmic equivalent of taking out the rubbish and the zero-G Guy Fawkes eventually burned up in the atmosphere as planned. In July, a Las Vegas property magnate called Robert Bigelow launched an experimental inflatable space hotel. The unconventional inn in the sky was crewed by cockroaches and Mexican jumping bean moths. In November, Russian cosmonaut Mikhail Tyurin hit the longest golf shot in history from the ISS. A Canadian golf manufacturer paid for the stunt.

Water on Mars

The universe may not be such a lonely place after all. Earlier this month, Nasa scientists revealed the first evidence for flowing water on Mars. By comparing images taken by the now defunct Mars Global Surveyor satellite in 2001 and 2005 they saw tell-tale grooves cut by water bursting out of a crater wall and flowing between boulders. Researchers had previously found evidence that ancient lakes once dotted the Martian surface and vast quantities of water are locked up as ice at the planet's frosty poles. The flowing water would have quickly boiled and evaporated despite temperatures ranging from -8C and -100C because of the extremely low pressure. But the fact that it was there ups the odds for life on the red planet.

Extinction fears

In July, scientists warned extinctions are happening at 100 to 1,000 times the natural rate in geological history. Nearly a quarter of mammals, a third of amphibians and more than a tenth of bird species are threatened. Climate change is expected to force a further 15% to 37% of species over the edge. In November we learned that the current rate of extraction from the seas is predicted to cause the collapse of all the world's fish and shellfish stocks by 2048. Another study suggested that tigers would become extinct in just two decades.

Mature mums

The bounds of reproductive medicine were pushed a little further in July when a child psychiatrist became the oldest woman in Britain to have a baby. Patricia Rashbrook, 63, had the boy by caesarean section after receiving fertility treatment in eastern Europe. The birth provoked criticism from groups who said that her age would mean she was not physically able to bring him up.

Neanderthal refuge

Neanderthals may have clung on in Europe until as recently as 24,000 years ago - 11,000 years later than scientists had thought. A cave that was perhaps their last European refuge was revealed in a study published in September. Gorham's cave in Gibraltar was home to 15 neanderthals.

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The devastating climate effects of even a small nuclear war

The continent-hopping doesn't seem to stop for me. Am in San Francisco at the moment, covering the American Geophysical Union's Fall meeting. These Americans know how to work a man hard, so no time for any major sightseeing yet (though I did go out to Monterey Bay on sunday and got a stunning view of the surf).

An interesting story from the first day of the meeting concerning the climate effects of a small-scale nuclear war. The researchers say that less than 100 Hiroshima-sized blasts would have devastating long-term effects on the climate. Crops would be out of action for five years, average temperature around the world would crash for ten years and the ozone layer would be decimated.

It's sobering given the seeming indifference to nuclear proliferation these days from major governments. India has just signed a deal with the US, for example, to share nuclear technology, ostensibly for its civilian programme. Both countries have hailed it as a major diplomatic breakthrough. There were reports that George Bush said recently that small-scale nuclear weapons could justifiably have been used to quell unrest in Iraq if necessary.

The American scientists behind the report argue that smaller conflicts are far more likely now than any major armageddon-type event (using 1000s of warheads) between the US and the Soviet Union was in the 1980s. They add that a confluence of three factors makes now the most dangerous time in history for human civilisation: increased nuclear proliferation; the migration of human populations into megacities and increased political instability.

Ther papers modelling the effects on climate and the one on human impacts are both available for discussion online.

Nuclear weapons pose the single biggest threat to the Earth's environment, scientists have warned.

In a new study of the potential global impacts of nuclear blasts, an American team found even a small-scale war would quickly devastate the world's climate and ecosystems, causing damage that would last for more than a decade.


Speaking at the American Geophysical Union's meeting in San Francisco yesterday, Richard Turco of UCLA said detonating between 50 and 100 bombs - just 0.03% of the world's arsenal - would throw enough soot into the atmosphere to create climactic anomalies unprecedented in human history.

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He said the effects would be "much greater than what we're talking about with global warming and anything that's happened in history with regards volcanic eruptions".

According to the research, tens of millions of people would die, global temperatures would crash and most of the world would be unable to grow crops for more than five years after a conflict.

In addition, the ozone layer, which protects the surface of the Earth from harmful ultraviolet radiation, would be depleted by 40% over many inhabited areas and up to 70% at the poles.

Alan Robock, the co-author of the study, told Guardian Unlimited: "Nuclear weapons are the greatest environmental danger to the planet from humans, not global warming or ozone depletion."

There are around 30,000 nuclear warheads worldwide, 95% of which are held by the US and Russia.

In addition, there is enough unrefined nuclear material to make a further 100,000 weapons.

Human costs
It was Prof Turco who coined the phrase "nuclear winter" in the 1980s to describe the potential apocalyptic global consequence of all-out nuclear war.

In this study he and Prof Robock led research teams to create models of the impacts from nuclear blasts.

They examined an exchange of 100 Hiroshima-sized nuclear bombs (15 kilotons each) between two countries, a conflict they argued was well within the ability of many emerging nuclear states.

The results showed that the most densely packed countries would fare worst in the aftermath of a nuclear war. India and Pakistan could face 12m and 9m immediate deaths respectively, while an attack on the UK would cause almost 3m immediate deaths.

A single nuclear blast in a major urban area would kill more than 125,000 people in the UK, injuring a further 100,000.

"Most of the human population is moving into very concentrated cities. At the same time, nuclear proliferation is accelerating again: we have Pakistan and India, Iran and North Korea," said Profe Turco.

While human losses would be constrained by geography, the environmental impacts of the bombs would spread worldwide.

Black smoke
In the 100 warhead scenario, more than 5m tonnes of sooty black smoke would spew from the resulting firestorms. This smoke would float to the upper atmosphere, get heated by the sun and end up being carried around the world.

The particles would absorb sunlight, preventing it from reaching the surface, which would result in a rapid cooling of the Earth by an average of 1.25C.

"This would be colder than the little ice age, the largest climate change in human history," said Prof Robock.

The model also showed that the smoke would stay in the upper atmosphere far longer than anyone had previously thought.

Older models had assumed that the smoke would linger for around a year, as has been observed with the dust from volcanic eruptions. However, using improved atmospheric data the new study showed that the climate would still be suffering a decade on from the initial conflict.

"Far removed from the conflict, there would be large impacts on agriculture - there would be less precipitation and less sunlight; it would be a huge shock to agriculture everywhere," said Prof Robock.

There is a precedent for this sort of climactic change: major volcanic eruptions in the past have thrown global ecosystems into temporary turmoil.

The eruption of Mount Tambora in 1815 was the biggest such event on record. The resulting cloud of ash spread around the world and caused crops to fail the following year in North America and Europe, resulting in the worst famine of the century.

Shock to the system
The scientists said a sudden change to the Earth's ecosystem because of nuclear blasts would be worse than any of the effects predicted by global warming due to greenhouse gases.

"Global warming is a problem and we certainly should address it but in 20 years, the temperature might go up by a few tenths of a degree and it will be gradual," said Prof Robock.

"We'll be able to adapt from some of it. But the climate change from even the small nuclear war we postulated would be instantaneous and such a shock to the system"

He said that the results should act as a warning to the international community.

"Proliferation is very dangerous - even using a couple of weapons is so much worse than anyone can imagine. I think the world should be much more concerned about proliferation than we are."

Prof Turco said that the end of the cold war had taken people's minds focus off the potential dangers of nuclear war.

"Look at 9/11 - there were 3,000 fatalities in that attack and that's considered a watershed in terms of terror that can be inflicted on a country. But in fact that's really a minor event to what's possible," he said.

"I can't imagine what would happen if there was a detonation in London: people would head to the countryside, there would be fallout everywhere, the country would shut down."

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