# Impact Outweighs - Probability

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## Impact Outweighs - Probability

And you thought airplanes were scary – you’re more likely to die from an asteroid

Lewis 97 (John S. Lewis is a professor of planetary science at the University of Arizona’s Lunar and Planetary Laboratory, former professor of space sciences at MIT. “Escaping the ultimate disaster--a cosmic collision.”  Futurist, Jan/Feb97, Vol. 31, Issue 1. EBSCOhost. TDA)

There is a wide range of lethal consequences of asteroid and comet collisions: The death or injury of individuals struck by a falling meteorite affects probably one to 10 people per century. Villages or cities can be struck by showers of meteorites from high-altitude airbursts about once per century. Also about once per century, iron or other physically strong meteorites may resist atmospheric breakup to strike the surface as a single crater-forming body or as a compact shower of iron shrapnel. And low-altitude megaton air-bursts should also strike at populated areas every century or so, setting fires, shattering windows, and demolishing buildings over an area of hundreds to thousands of square kilometers. About half of impact fatalities are caused by the smaller, more frequent, localized events. About a quarter of the total deaths arise from tsunamis caused by impacts (once every 10,000 years), and another quarter from continental cratering events and low airbursts. Every 70,000 to 1 million years, a global billion-casualty killer will strike Earth: Collisions of 10-gigaton objects may occur about every 70,000 years; 100-gigaton explosions occur about once per 250,000 years; and 1,000-gigaton events occur a little more than once per 1 million years. If your projected life-span is about 75 years, that means the probability that you will be killed in a global impact event is between 0.01% and 0.1%. By comparison, the probability that you will be killed in a civil airliner crash is 0.005%. The long-term average death rate from impacts is 4 billion people per million years, or 4,000 people per year worldwide. The people of the United States make up about 5% of the global population, so the average American death rate from global-scale impacts is about 200 per year. By comparison, the death rate of American citizens from commercial aircraft crashes is 100 people a year.

## Impact Outweighs Nuclear War

Extinction is categorically different from any other impact—even if they win a nuclear war kills 99 percent of the population, an asteroid strike still outweighs by an order of magnitude.
Matheny 7 (Jason G., Department of Health Policy and Management, Bloomberg School of Public Health, 2007, “Reducing the Risk of Human Extinction”, NB
http://jgmatheny.org/matheny_extinction_risk.htm)

Even if extinction events are improbable, the expected values of countermeasures could be large, as they include the value of all future lives. This introduces a discontinuity between the CEA of extinction and nonextinction risks. Even though the risk to any existing individual of dying in a car crash is much greater than the risk of dying in an asteroid impact, asteroids pose a much greater risk to the existence of future generations (we are not likely to crash all our cars at once) (Chapman, 2004 ). The "death-toll" of an extinction-level asteroid impact is the population of Earth, plus all the descendents of that population who would otherwise have existed if not for the impact. There is thus a discontinuity between risks that threaten 99% of humanity and those that threaten 100%.

## Small Asteroids = damage

Asteroid Impacts outweigh all others, even a small asteroid ½ a kilometer in diameter could cause widespread disaster and famine.

Urias et. Al 96 [Research Paper for Air Force 2025, Planetary Defense: Catastrophic Health Insurance for Planet Earth pg. 7- 8, “Vulnerabilities,” October 1996, SM, accessed: 7/11/11, http://csat.au.af.mil/2025/volume3/vol3ch16.pdf]

Regardless of the tendency to downplay the ECO threat, the probability of an eventual impact is finite. When it happens, the resulting disaster is expected to be devastatingly catastrophic. Scientists estimate the impact by an asteroid even as small as 0.5 kilometers could cause climate shifts sufficient to drastically reduce crop yields for one or several years due to atmospheric debris restricting sunlight. Impacts by objects one to two kilometers in size could therefore result in significant loss of life due to mass starvation. Few countries store as much as even one year's supply of food. The death toll from direct impact effects (blast and firestorm, as well as the climatic changes) could reach 25 percent of the world's population. 8 Although it may be a rare event, occurring only every few hundred thousand years, the average yearly fatalities from such an event could still exceed many natural disasters more common to the global population impact by an asteroid even as small as 0.5 kilometers could cause climate shifts sufficient to drastically reduce crop yields for one or several years due to atmospheric debris restricting sunlight. Impacts by objects one to two kilometers in size could therefore result in significant loss of life due to mass starvation. Few countries store as much as even one year's supply of food. The death toll from direct impact effects (blast and firestorm, as well as the climatic changes) could reach 25 percent of the world's population. 8 Although it may be a rare event, occurring only every few hundred thousand years, the average yearly fatalities from such an event could still exceed many natural disasters more common to the global population. Because the risk is small for such an impact happening in the near future, the nature of the ECO impact hazard is beyond our experience. With the exception of the asteroid strike in Shansi, China, which reportedly killed more than 10,000 people in 1490, ECO impacts killing more than 100 people have not been reported within all of human history. 9 Natural disasters, including earthquakes, tornadoes, cyclones, tsunamis, volcanic eruptions, firestorms, and floods often kill thousands of people, and occasionally several million. In contrast to more familiar disasters, the postulated asteroid impact would result in massive devastation. For example, had the 1908 Tunguska event happened three hours later, Moscow would have been leveled. In another event occurring approximately 800 years ago on New Zealand's South Island, an ECO exploded in the sky, igniting fires and destroying thousands of acres of forests. 10 If such an event were to occur over an urban area, hundreds of thousands of people could be killed, and damage could be measured in hundreds of billions of dollars. 11 A civilization-destroying impact overshadows all other disasters, since billions of people could be killed (as large a percentage loss of life worldwide as that experienced by Europe from the Black Death in the 14th century). 12 As the global population continues to increase, the probability of an ECO impact in a large urban center also increases proportionally. Work over the last several years by the astronomical community supports that more impacts will inevitably occur in the future. Such impacts could result in widespread devastation or even catastrophic alteration of the global ecosystem