Clark R. ChapmanSouthwest Research Inst.Boulder, Colorado

Clark R. ChapmanSouthwest Research Inst.Boulder, Colorado

““Managing Global Scale Disasters”Managing Global Scale Disasters”Western Psychological AssociationWestern Psychological AssociationIrvine, California 12 April 2002Irvine, California 12 April 2002

““Managing Global Scale Disasters”Managing Global Scale Disasters”Western Psychological AssociationWestern Psychological AssociationIrvine, California 12 April 2002Irvine, California 12 April 2002

The Threat to Earth from Asteroids and Comets…The Threat to Earth from Asteroids and Comets…

and Possible Countermeasuresand Possible Countermeasures

The Hazard from Asteroids and Comets

Each year, there is a 1-in-200,000 chance that an asteroid or comet more than one kilometer wide will strike the Earth.

40 percent of these objects remain to be found, and could strike without warning, threatening the future of civilization.

This extreme example of a natural disaster (a tiny chance of happening, but with huge consequences) challenges a rational response by citizens and policy-makers.

The processes that formed the planets 4.6 billion years ago left smaller comets and asteroids…

some of which occasionally cross the Earth’s orbit and can strike our planet if it happens to be there at the same time.

Small impacts happen frequently

Larger impacts happen rarely in human history...

This Siberian forest (the size of a major city) was felled in 1908 by a 15-Megaton asteroid explosion

Still larger, globally destructive impacts happen very rarely...

Comet Shoemaker- Levy 9 struck the planet Jupiter in 1994, blackening parts of its atmosphere larger than the whole planet Earth

But Earth is struck by devastating objects less often… every million years

Image from Peter McGregor and Mark Allen, Image from Peter McGregor and Mark Allen, ANU 2.3m telescope.ANU 2.3m telescope.

HUGE impacts have happened before…65 million years ago

What Do We Know About the Impact Hazard?

How many asteroids and comets there are of various sizes in Earth-approaching orbits (hence, impact frequencies are known).

How much energy is delivered by impact (such as the TNT equivalence, size of resulting crater).

How much dust is raised into the stratosphere and other environmental consequences.

Biosphere response (agriculture, forests, human beings, ocean life) to environmental shock.

Response of human psychology, sociology, political systems, and economies to such a catastrophe. That’s where YOU come in!That’s where YOU come in!

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Classification of Hazards

High Altitude Disintegration (Brilliant Flash of Light) Projectile fragments and disperses at high altitudes (over 40 km) Negligible surface damage

Local/Regional Effects (Blast Damage, Tsunami) Projectile explodes in lower atmosphere or craters surface Severe localized damage from blast or flooding by tsunami

Global Damage (Environmental Disaster) Short-term global-scale climatic changes (e.g. impact winter) Global loss of food crops leads to large-scale famine, disease,

and possible breakdown of civilization

Mass Extinction (Environmental Holocaust) Severe global environmental destruction (e.g. K/T event) Many species lost forever; all, or nearly all, human beings die

DecadeDecade

Millennium

Millennium

Million Years

Million Years

Hundred

Million YearsHundred

Million Years

Chief Environmental Consequences of Impacts

Is Civilization Robust or Fragile? A State of Mind…?

Arguments for Fragility Modern people are disconnected from nature,

survivability Technology is ever more specialized People are interdependent on distant resources, other

nations If societal breakdown spawns violence, modern

weaponry is very dangerous

 Arguments for Robustness Technological refugia exist (such as bomb shelters) Society has become experienced in disaster recovery Technological know-how has become pervasive Historical precedence; recovery from WWII was rapid

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Risk vs. Scale of Impact

Annual fatalities peak for events near the “threshold size”, about 2 km

Orange/yellow zone illustrates our range of uncertainties for agricultural disaster due to stratospheric dust

A Royal Flush

It is more likely that a mile-wide asteroid will It is more likely that a mile-wide asteroid will strike Earth next year than that the next poker strike Earth next year than that the next poker hand you are dealt will be a royal flush.hand you are dealt will be a royal flush.

Odds:1 to 649,739

20th Century Catastrophes: We have much more to worry about!

Averaged over long durations, the death rate expected from impacts is similar to that from volcanoes.

Source: John Pike

Chances from Dying from Selected Causes (for U.S.A.)

By terrorism (year 2001)

By terrorism (since 1970)

Fatality Rates Compared with Accidents and Natural Hazards

Mitigation Options

Spaceguard Survey (ongoing telescopic search)

90% of hazardous NEAs may be found by 2010, certified as safe.

Very unlikely: one is found that will strike Earth within decades.

Deflect Asteroid away from Earth (nudge it from threatening path)

Spacecraft technologies exist to deliver deflection devices to threatening asteroid, given years/decades warning and lead-time.

Low-thrust device options: rocket engine, solar sail, mass driver, even “paint-it-black” to take advantage of Yarkovsky Effect

Powerful devices: anchored bombs or stand-off neutron bomb

Standard Hazard Mitigation (THIS IS FOR YOU TO FIGURE OUT!)

Extrapolate civil defense/natural disaster management from local to world context (e.g. store food supplies, evacuate countries around ground zero, prepare for post-disaster crisis).

Headline: “Mile-Wide Asteroid Will Hit in 2028”

Which is least likely to be correct?

A. The news report is wrong due to bad or

hyped journalism.

B. The scientific forecaster goofed. We’re safe.

C. The astronomers erred. The asteroid is tiny;most of the world is safe.

D. An asteroid will hit Earth in 2028.

The correct answer is “D”:

A, B, and C are all much more likely to explain the headline.

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The “Scary” Case of 1997 XF11

In March 1998, head-lines warned of pos-sible impact in 2028.

The next day, old data ruled it out…but the prediction was badly mistaken.

Prediction is the Event

Scientists who predict think of predictions as dry scientific results, with objective error-bars.

Users of such predictions are mobilized into action by the prediction.

The predicted event may not happen as predicted; it may or may not have consequences. The predictions always have consequences.

Predictions of emotionally laden disasters result in subjective, sometimes irrational responses.

Predictions must be made with social responsibility, whether of a potential terrorist operation or of an asteroid impact. Astronomers are learning!Astronomers are learning!

The Torino Scale

Events Having No Events Having No Likely ConsequencesLikely Consequences

Events MeritingEvents MeritingCareful MonitoringCareful Monitoring

Events MeritingEvents MeritingConcernConcern

ThreateningThreateningEventsEvents

CertainCertainCollisionsCollisions

How the Torino Scale is Calculated: From the Probability of Impact and Size

Current Dilemma. (Work is Starting to Fix it)

Our SwRI “White Paper”: Highlights Lack of Planning

Findings: Evaluation, Warning, and Mitigation

Existing structure is disorganized: Astronomers are just starting to learn how to communicate, but relevant agencies (e.g. FEMA) aren’t prepared to listen and act.

Asteroid deflection scenarios have been conceived, but no serious systems engineering or planning has been done to deal with various possible cases.

There is no known consideration by civil defense and disaster management agencies, let alone any assignment of responsibilities to relevant agencies.

No US governmental scientific advisory body has formally established the priority that the impact hazard should command with respect to other national priorities.

There Are Some Hopeful Signs

The British government debated the impact hazard and has started (a bit) to do something

The Organization for Economic Cooperation and Development (OECD) Global Science Forum decided in January 2002 to make NEO’s one of its top priority projects through 2003

SAIC and the US Air Force Space Command are investigating how to establish a “Natural Impact Warning Center”

Public interest remains high, even if there is very little governmental funding

Some Salient Facts about the Impact Hazard

It is notnot a “Deep Impact” or “Armageddon” shoot-em-down just before they hit scenario (sorry, Benny!)

For asteroids, orbiting in the inner solar system, it is a case of finding them decades in advance of an impact…with long lead-times for mitigation: For every asteroid with <1 year warning time, there are 50 with 5 decades of lead-time (but comets are another matter)

It is one of the few big hazards for which it is technologically feasible, with some confidence, to stop the catastrophe from happening (by deflection)

Near-miss scares and cries of “Wolf!” are much more likely than an actual catastrophic impact

Why are the big/rare ones so much more important than Tunguskas?

Only asteroids larger than ~1 mile across can be globally destructive and threaten civilization

For every devastating 15-MT Tunguska blast, there are ~100 earthquakes, floods, and typhoons that are equally destructive

Cost-effectiveness drops sharply with size: the average annual fatalities drop while the costs of finding the objects and responding to them rises

But, there are contrary viewpoints and interests: On a politician’s But, there are contrary viewpoints and interests: On a politician’s “watch”, why would he/she care about what might happen decades “watch”, why would he/she care about what might happen decades from now? And there are “Star Warriors” in the DoD who would like from now? And there are “Star Warriors” in the DoD who would like to test their inventions and try shooting down small asteroids. And to test their inventions and try shooting down small asteroids. And astronomers who would love to have more and bigger telescopes.astronomers who would love to have more and bigger telescopes.

Conclusions…and Transition to the Psychological and Sociological Perspectives

The impact hazard is REAL but it is VERY UNLIKELY to happen during our lifetimes

Its potential consequences are horrific… exceeding any other natural hazard and equalling all-out nuclear war

We could avert a threatened impact

In a post-September 11th world, it is difficult (for me) to predict how people might react to near-misses, huge-but-low-probability disasters, bombs in space, and other impact hazard issues