Dicembre 2012: ecco gli scenari più o meno plausibili

Si parla tanto della fine del mondo fissata (secondo il calendario Maya) per il mese di dicembre del 2012. Indubbiamente si tratta di una profezia male interpretata, in ogni caso ecco quali sono i rischi reali per la Terra per i prossimi anni (utilizzando una scala da 0 a 10): si va dall'attacco alieno, alla terza guerra mondiale, dal collasso delle api, alla collisione fra pianeti...

1. Alien invasion/government confirmation of extraterrestrial contact
Where do you start? Alien invasion has been the subject of great works of fiction since HG Wells published War of the Worlds in 1898. Fear of such an attack, be it from Mars, a species from outside our galaxy or beings from other dimensions, tends to wax and wane with the general state of anxiety on Earth - researchers have found that fear of attack by aliens tends to rise at times of heightened fear about more terrestrial threats. Believers cite increasing numbers of UFO sightings, the supposed crash of a disc at Roswell, New Mexico, in 1947 and several seemingly credible photographs and videos of strange craft in our skies as evidence that such a threat is increasing.

Evidence: Photographs, videos, official releases that prove how governments around the world have monitored UFO activity for more than 50 years, stories by abductees... the list goes on and on. But do any of these suggest that we're about to be taken over by a race of grey humanoids with large black eyes at any time in the future, let alone in 2012?

Likelihood: 0.1/10

2. Nibiru/Planet X/Wormwood

Thousands of web forums and sites propose the belief that sometime in the early years of the 21st century, a previously undiscovered planet will collide with or pass very close to the Earth destroying civilisation or causing a massive planetary cataclysm. Nibiru was invented in the late 1960s by Zechariah Sitchin in a book. According to Sitchin, Nibiru is a planet in our solar system which follows an erratic orbit bringing it into the inner system every 3,700 years. But Sitchin never suggested that it would threaten the Earth. Some even suggest that Nibiru is a brown dwarf sister to our own sun and will first be seen towards the end of this year.
Evidence: Very little. Some point to the 2005 announcement by Nasa that a 10th planet had been discovered on the outer fringes of our solar system and many think that it will pass close to the Earth in 2012. But this 10th planet is most certainly not moving into the inner solar system.

Likelihood: 0.2/10

3. Solar catastrophe

This is one of the few doomsday scenarios connected with the end of the Mayan calendar that may actually be based on some science. In this scenario a vast solar flare or expulsion of gases from the sun in December 2012 will engulf the Earth wreaking havoc upon mankind and the planet's ecosystems. There is no evidence that such catastrophic events happened in the past.

Evidence: There may be some correlation between the observed 11-year solar cycle and the time cycles seen in the Mayan calendar although this evidence is rather weak. But whilst a solar flare from the sun could cause problems such as satellite damage and injury to unprotected astronauts and blackouts, the flare itself would not be powerful enough to destroy Earth, certainly not in 2012. In the far future, when the sun runs out of fuel, most scientists accept that it will swell into a red giant and engulf the Earth. But rather than happening in 2012, this event will happen no sooner than five billion years from now.

Likelihood: 0.3/10

4. Magnetic pole shift

A large body of doomsday believers think that a dramatic reversal of Earth's magnetic poles is imminent and that it will trigger a reversal of the planet's rotation and the subsequent catastrophic events. They point to evidence of pole shifts in Earth's past and claim that these reversals can be calculated by studying sunspots or magnetic field theory. Many believe that the Mayans and the ancient Egyptians discovered evidence of pole reversal events in the future and that the secrets have been covered up by today's governments.

Evidence: Some. Work by scientists at Princeton University and Paul Sabatier University in Toulouse, France, indicates that Earth did rebalance itself 800 million years ago. They studied magnetic minerals in sedimentary rocks in Norway and found that the north pole shifted by more than 50 degrees (a quarter the distance from pole to pole, in effect) in under 20 million years. Other scientists have also discovered that seasonal movements in both polar regions do effect the positioning of the poles. But where the scientists and the "doomers" differ greatly is over the timescale of any potential pole shift - while the apocalyptic visionaries believe such a switch could happen in a very short time scale, geologists think that it would happen over a period of one million years.

Likelihood: 1/10

5. Supervolcano

A supervolcanic eruption would be larger than any volcanic eruption in man's history and would happen when magma rose into the Earth's crust but would be unable to break through. The resulting build in pressure would mean that at some point a huge area of land would be devastated as the magma blasted skyward. Such an event would, it is postulated, blast millions of tons of debris and poisonous gases into the atmosphere, and could either plunge the world into a so-called nuclear winter triggering an ice age or, at worst, wipe out life in parts or all of the planet.

Evidence: Most of the concern about 2012 and supervolanoes centres on the so-called super-caldera underneath Yellowstone Park in the United States. Satellite images have, in the last few years, shown changes in the the movement of molten rock 10 miles under the surface. Wayne Thatcher of the US Geological Survey told Nature magazine: "We know now how mobile and restless the Yellowstone caldera actually is." Nobody actually knows whether the caldera will blow or, if it does, when such an event could take place.

Likelihood: 1/10

6. World War III

Almost as soon as the Second World War in 1945 ended and with a standoff between the Western Allies and the Eastern bloc in place through the middle of Europe, there was rising anxiety that the world would be consumed by another epic conflict. When Russia exploded its first atomic bomb just two years later, a nuclear arms race between East and West began. The invention of hydrogen (thermonuclear) devices only accelerated the race which peaked in 1962 during the Cuban Missile Crisis when the world came closest to an all-out nuclear exchange between the United States and the Soviet Union. The build-up of weapons continued throughout the 1970s and 1980s but a dedicated hotline between the Kremlin and the White House and some arms control treaties reduced the threat of an accidental nuclear war. The threat diminished in the 1990s with the collapse of the Soviet Union.

Evidence: Today, the fears of a nuclear exchange centre on the rising power of China and the American response and the possibility of wars between India and Pakistan or North and South Korea escalating into global conflicts.

Likelihood: 1.5/10

7. Mass casualty terrorism

Since September 11, 2001 and the deaths of nearly 3,000 people in New York and Washington DC there have been fears about al Qaeda or another terrorist network acquiring weapons of mass destruction and devastating a major western city or releasing a chemical or biological attack. Statements by governments about the risk of such an attack have done little to lessen the anxiety with both the British and American administrations raising the spectre of a stray nuclear weapon being detonated in a major city. Dick Cheney, the former US vice president, is reported to have stated that he is haunted by thoughts of a mushroom cloud rising over an American downtown skyline. Many conspiracy theories, particularly those who believe that the 9/11 attacks were actually planned and executed by rogue elements in the US administration, believe that there will be a so-called "false flag" nuclear attack to divert attention from the west's woes and usher in an era of martial law and totalitarian government.

Evidence: Osama bin Laden famously declared a few years ago that his organisation has several nuclear devices but they were only a "deterrent". There has been some concern about several "loose" nukes from the former Soviet Union, particularly six so-called "suitcase" nukes. But there is no evidence that al Qaeda or anybody else holds nuclear weapons and several attempts by terrorists in the UK to make nerve or biological agents have proved inept failures. Nevertheless, concern now centres upon the instability of the Pakistan regime - a nuclear-equipped country - and fears that al Qaeda or a Taliban group could topple the government and get its hands on nuclear weapons.

Likelihood: 2/10

8. Peak oil

The reduction of global oil stocks is, of course a reality, with the world's economies consuming - financial collapses excepted - ever-increasing amounts of the black gold. But peak oil theory centres around supply and demand and postulates that, at some point, demand will outstrip supply. When is this likely to happen? Some believe that it already has while others think that it is likely to happen some time between now and 2020. A number of doomer sites link peak oil with the end of the Mayan calendar in 2012. Demand for oil outstripping supply would have huge consequences around the world given that most economies are powered by oil, agriculture is completely dependent upon it for fertilisers and pesticides and the plastics industry is based on oil extraction. A collapse in social order following a peak in oil production is, therefore, something to be taken seriously.

Evidence: Peak oil is a near certainty but two questions remain: when will it happen and will the world have developed alternative sources of fuel in time? M. King Hubbert created the theory behind peak oil in 1956 to accurately predict that United States oil production would peak between 1965 and 1970. The theory has successfully predicted the decline from oil fields and regions subsequently. Optimistic observers do not believe that peak oil will occur before 2020 but admissions by some oil companies that they have overstated the reserves held underground have raised fears that we are at or may already have passed the peak. A decline in investment in new oil fields and plant during the global recession has only served to emphasise our total dependence upon a finite resource.

Likelihood: 4/10

9. Bee colony collapse

Thirty-six per cent of the commercial beehives in the US were lost to colony colapse disorder [CCD] in the winter of 2008. The syndrome, in which all of the worker bees in a colony die off suddenly, leaving nothing but a solitary queen wandering alone on empty frames, has spread to several countries in Europe already including France, Belgium, Italy, Portugal and Spain. Several causes of the disease have been suggested, including the almost universally present varroa mite, certain pesticides, Israeli acute paralysis virus, climate change and mobile phone broadcasts, but none have yet been proved to be the culprit. No cure has been found either, and as cases are reported in new countries the likelihood of a global pandemic leading to the extinction of the honeybee becomes a real possibility.

Evidence: Apart from the loss of the honey crop, without the honeybee several crops key to human life would be wiped out, including the soya bean, cotton, brassicas, several kinds of nut including brazil nuts and almonds, grapes, apples and sunflowers, the source of a large proportion of the world's vegetable oil. Thirty per cent of the world's food is directly traceable to the action of bees. If they became extinct severe shortages, starvation, violence and riots would surely follow.

Likelihood: 7/10

10. Environmental collapse

Today's mantra is climate change or man-made global warming. In previous decades pollution, soil depletion, the destruction of the ozone layer and an imminent ice age were the ecological catastrophes that faced us. There is, of course, no doubt that man's impact upon his environment is getting worse although a large body of opinion believes that global warming is a liberal conspiracy and that the world has actually been cooling over the last decade. A total environmental collapse brought about by runaway warming, toxic poisoning of the seas of parts of the inhabited areas of the world or a tipping point with some of the most crucial species (see Bee colony collapse above) would have a huge impact upon civilisation and could render parts of the world near uninhabitable.

Evidence: Few scientists dispute that the global average temperature has been rising for at least a century. The Intergovernmental Panel on Climate Change (IPCC) 2001 report concluded that the average surface temperature of the Earth had risen by 0.6C during the 20th century. The IPCC found that, in terms of the global average temperature, the 1990s were very likely (a 90-99% chance) to have been the warmest decade since records began in 1861, and that 1998 was the warmest year.

Likelihood: 7/10