The Doomsday Clock is a symbolic clock face, maintained since 1947, in the wake of the advent of nuclear weapons, by the board of directors of the Bulletin of the Atomic Scientists at the University of Chicago.
The closer the clock is to midnight, the closer the world is estimated to be to global disaster. The most recent officially announced setting, five minutes to midnight (11:55pm), was made on 10 January 2012. The reasons given for the +1 change were ‘lack of global political action to address nuclear weapons stockpiles, the potential for regional nuclear conflict, nuclear power safety, and global climate change.’
Reflecting international events dangerous to humankind, the clock’s hands, at time of writing, have been adjusted twenty times since its inception in 1947. So what are the doomsday events that scientists fear might wipe out civilization as we know it? We will have a look at them…
Space objects strike the Earth all the time, though extinction-level impacts occur only once every 100 million years. A civilization-killing asteroid would have to be a mile across, and are uncommon, but the chances of a smaller asteroid causing a more localized disaster are much higher. It is known that there are a large population of as-yet-undiscovered objects several hundred yards across. One that is known, a 300-yard-wide asteroid called 99942 Apophis, is due to pass within the orbits of earth satellites in 2029.
In 1918 an influenza pandemic, called the Spanish Flu, in the course of two and half years killed 50 to 80 million people. In relative terms If the next influenza pandemic is similar in lethality to 1918’s, the equivalent death toll would be 210 million. The next pandemic could be even more lethal. Thanks to advances in biotechnology, it will become increasingly possible to custom-tailor a pathogen’s lethality. “We’re on the cusp of what could be a very frightening time,” says Charles P. Blair, director of the Terrorism Analysis Project at the Federation of American Scientists. “I think in the very near future you’re talking about a potential extinction event.”
Gamma-ray bursts are flashes of gamma rays associated with extremely energetic explosions that have been observed in distant galaxies. The gamma rays and charged particles for a few seconds outshine the rest of the stars in the universe combined. They are thought to be caused by the death of large stars, which, having used up their nuclear fuel, collapse inward into a black hole, which then devours the star from inside out. Out of this paroxysm of destruction, powerful beams of energy burst from both poles. It has been hypothesized that a gamma-ray burst in the Milky Way, pointing directly towards the Earth, could cause a mass extinction event, but do not fear too much, these events are very rare and all observed gamma-ray bursts have originated from outside the Milky Way galaxy.
Fallout from a nuclear war or a super-volcano could put enough sunlight-blocking dust in the air to cause the opposite problem to global warming, that is, a deep plunge in surface temperatures. If the earth stayed cool long enough, a worse catastrophe could ensue. most of the incoming solar radiation would be reflected back into space and the planet would settle into a stable state at about minus 50 degrees F. Then, in 1992, CalTech geobiologist Joseph Kirschvink proposed that the earth had once spent long stretches of time almost entirely frozen over, leaving evidence of glacial deposits in the tropics. Life clung on in a few sanctuaries heated by volcanic springs. It could happen again.
Solar storms include Solar Flares, Coronal Mass Ejections and Geomagnetic Storms. During the worst solar storm ever recorded, in 1859, the currents were so intense that telegraph lines burst into flames. “If we had a storm like that today, it would be possibly quite catastrophic,” says Jeffrey Love, a geomagnetic researcher with the U.S. Geological Survey. “Months without electricity could cause losses of trillions of dollars and basically wreck the economy.”
These eruptions are thousands of times larger than normal volcanic eruptions and send masses of ash into the atmosphere. Massive eruptions have been taking place every 600,000 years or so—and the last one was 640,000 years ago. Apart from the loss of life in the local area, global air traffic would be effected for months or years.
Throughout the earth’s history, the north and south magnetic poles have swapped places, a phenomenon known as geomagnetic reversal. The last time they flipped was 780,000 years ago and perhaps we are due. It is thought that the reversal could cause the geomagnetic field to temporarily collapse, disrupting everything from power grids to gas pipelines to communications satellites.
Nuclear tensions have subsided considerably since the end of the Cold War, however the threat remains. Terrorist groups and rogue states remain a worry along with traditional worries. A study published in 2008 by the journal Physics Today suggests that a regional war involving as few as 100 bombs could cause a nuclear winter. The most optimistic predictions of the effects of a major nuclear exchange predict millions of deaths within a short period of time. More pessimistic predictions argue that a full-scale nuclear war could potentially bring about the extinction of the human race. The threat of nuclear war is a real threat that many of us just simply forget about, perhaps we have been lucky so far.