January 1994 (vol. 10, #2) 1601 N Tucson Blvd
#9, Tucson AZ 85716 c 1994 Physicians for Civil Defense
This week's issue of Nature brings a detailed analysis of the risk of a cosmic impact severe enough to cause global catastrophe (Chapman and Morrison, 1/6/94). Although a subject of science fiction (e.g. Lucifer's Hammer by Larry Niven and Jerry Pournelle and The Hammer of God by Arthur Clarke), the threat is not merely hypothetical. Over 140 terrestrial impact scars have been identified. In 1908, an impact with a comet or asteroid caused an area of devastation of 1000 sq km in the Tunguska River region of Siberia. A prehistoric collision with a 10-km asteroid may have caused mass extinctions. A bolide (explosion of a meteor) with the energy of the Hiroshima bomb occurs about once a year, generally at an altitude so high that the shock wave does not reach the ground. The events have been observed by surveillance satellites.
The explosion of a meteor that penetrates to within 25 km of the earth's surface can cause blast damage analogous to that of a nuclear weapon. The Tunguska event was the equivalent of a 10-20 MT blast. Civil defense studies show that the area of destruction scales as the explosive yield to the 2/3 power (Glasstone and Dolan, The Effects of Nuclear Weapons 1977).
Global climatic effects could result if the colliding object is larger than the ``global threshold.'' The event would have to inject into the stratosphere about 100 times as much aerosol as any of the major volcanic eruptions of the past two centuries. (It was indeed calculations of an ``impact winter'' that formed the basis of the ``nuclear winter'' hypothesis.) Such an environmental shock would curtail agricultural production during one growing season. ``The repercussions would be severe, as few nations store one year's worth of food,'' state the authors.
There are large uncertainties in the calculation of the energy required to produce this effect. Chapman and Morrison calculate a range from 1.5 x 104 to 107 MT, produced by objects 0.6 to 5 km in diameter.
About 163 asteroids with orbits crossing that of the Earth have been catalogued; the catalogue is probably less than 5% complete for objects less than 1 km in diameter.
The probability that a locally devastating, 1000-MT
event will occur somewhere on Earth during a person's lifetime
is approximately 1%. Surprisingly, the average American has a
much higher risk of dying from an asteroid impact than from many
other highly publicized hazards. However, Tunguska-class impacts
are 100 times less likely to occur in a heavily populated area
than other natural disasters. Between 1900 and 1985, there were
10 natural disasters that killed between 100,000 and 2,000,000
people each, including 4 earthquakes, 3 floods, 2 droughts, and
Chances of dying from selected causes (US)*:
*after Chapman and Morrison, Nature 367:39
The lower-limit risk for an impact is based on the assumption that 1.5 billion persons are killed by a 1.5 x 104 MT event, which occurs, on the average, every 70,000 years. The upper-limit risk assumes that a 107 MT event is required to cause this number of casualties. The probable frequency of such an event is 1 in 6 million years. The average expected number of local casualties ranges from 3 million up to 30 million if the effects of tsunamis (from ocean impacts) are included. The vast majority of the assumed casualties are due to climatic effects and synergistic impacts of social and ``ecosystem'' disruptions.
An extraterrestrial impact with global consequences is in the category of a ``rare/high consequence'' event it is overwhelmingly probable that zero persons will die of a catastrophic impact in the foreseeable future. It is instructive to compare societal response to this threat for which risk estimates, at least of impacts, are based on actual observations with the Chicken Little style response to purely hypothetical models and extrapolations such as Nuclear Winter and Global Warming and the Ozone Hole. [We have to try to prop up the sky in case it might be falling because if we wait for data, it might be too late.]
Chapman and Morrison argue for developing and deploying a system such as the ``Spaceguard Survey'' proposed by the NASA Near-Earth Object Detection Workshop. The estimated cost is $50 million for capital construction and $10 million per year for operation. The system could give a warning time of decades for collision with an asteroid. For long-period comets, the warning time might be only a few months.
A mitigation system, involving launch vehicles and explosive devices, would be far more costly. In addition, it would be controversial because nuclear explosives would be required. The authors argue for developing defenses only after a hazard is detected and only against impacts that might cause global catastrophe, even though impacts causing regional devastation are far more probable. The mitigation system itself would be subject to accident. Natural hazards are far more likely. Furthermore, ``it would be extremely difficult to discover and inventory all of the countless potential colliding objects down to tens of metres in size.''
An immediate issue raised by the study of impacts is the possibility that a high-altitude explosion of a meteor might trigger an inappropriate nuclear response from one of the world's increasingly numerous nuclear powers.
The authors conclude: ``By choosing whether or not to do something about this threat from the skies, society may establish a standard against which its responses to other hazards are measured.''
Questions that might occur to the reader: Should the EPA budget for monitoring and giving ``educational'' seminars on minute quantities of TCE (trichloroethylene) in water be diverted to the Planetary Science Institute of Science Applications International Corporation and the Space Science Division at NASA Ames Research Center, where Chapman and Morrison work? What about other hazards from the sky, say ballistic missiles? Their warheads pack a megatonnage much less than that of the Tunguska asteroid, but they are better targeted and more numerous.
Even today, asteroids may be better surveyed and more thoroughly understood than political and economic trends far more likely to have a global catastrophic impact (see p. 2).
However, there is a demographic bomb that has not yet appeared on many radar screens.
The first two U.N. population awards were given in 1983 to Indira Gandhi of India, whose government approved compul-sory sterilization in the 1970s, and to Qian Xinzhong, Minister-in-Charge of China's State Family Planning Commission. This year marked the peak for coercion in Chinese program. A national directive demanded that women with one child have an IUD inserted, one spouse of couples with two or more children be sterilized, and all unauthorized pregnancies be aborted. In that one year, 21 million sterilizations, 18 million IUD inser-tions, and 14 million abortions were done (Population Research Institute Review, Sept/Oct 1993).
Refugees fleeing China complain most bitterly about frequent policy changes that are implemented without warning. If a two-child limit in a given area is changed to a one-child limit, an abortion can be ordered on the spot, even an hour before birth (PRI, Jan/Feb 1993). Frequently, the abortions are carried out by untrained personnel under unsanitary conditions. The death rates among women aged 20 to 30 began increasing in parallel with the forced abortion program. Those who resist may be imprisoned and lose all their possessions.
These policies have the support of two past presidents of the National Organization for Women, Molly Yard and Eleanor Smeal, according to Stephen Mosher, head of the Claremont Institute. They may also have the support of US taxpayers, if the Clinton Administration reverses previous policies that denied support for coercive programs to the UN Population Fund.
One side effect of Chinese policy is a massive reduction in the number of female infants. All Chinese want to have a son to support them in their old age. The sex ratio of Chinese babies is now 118.5 boys for every 100 girls (normal is 105 or 106:100). Each year, about 800,000 Chinese boys are born who will never be able to find a wife (PRI Sept/Oct 1993). One Chinese farmer reported that in 1992, only one girl was born in his entire village. Previous practices of female infant-icide or abandonment are now being supplem-ented by high technology. If an ultrasound scan (which costs $35 to $50) shows that a woman is pregnant with a girl, an abortion is done. Ultra-sounds are also very popular in India and South Korea for the same reason (Nicholas Kristof, Ariz Daily Star 8/1/93).
The social consequences of having a huge excess of males, perhaps in ``bachelor villages,'' will be without precedent.
The goal of the Chinese government is to reduce the total fertility rate to 2.1 by the year 2000, and to ``stabilize'' (reach and maintain a constant population of 1.5 or 1.6 billion) by the middle of the 21st century. However, if present policies continue, there will actually be a significant population reduc-tion. Otto Scott predicts a Chinese population of 260 million by 2080, of whom 43% would be age 60 or older. At that time, annual births would be 1,000,000 and deaths 8,000,000 (Chal-cedon Report, Jan 1994). Of course, present policies will not necessarily continue.
Intelligence Digest (12/3/93) reports that top Russian operatives are holding secret talks with key communists in the African National Congress-South African Communist Party (ANC-SACP) alliance on the eve of its likely victory in the first all-race South African elections.
It is now being revealed that numerous ANC supporters had infiltrated into the country's security forces, as blacks from the prison department and police force brandish automatic rifles in the streets of Johannesburg, shouting ``Kill the Boers.'' There are also large-scale covert operations to kill black opponents of the ANC, mostly Zulus (Intel-ligence Digest 9/3/93).
Meanwhile, the US demonstrates its dedication to free-market principles by imposing production quotas on Russian uranium producers and pushing for an agreement to cut world output of aluminum, thus choking off exports of the only Russian products that the world currently wants to buy (Wall St J 1/12/94).
US policy notwithstanding, Russian strategic thinking divides the world into three sectors: the ``haves,'' the ``will-haves,'' and the ``have-nots.'' Russians intend to be in the second group, partly by means of controlling the third (Intel-ligence Digest 12/3/93).
``I would just like to give you this proposition: `The state of emergency preparedness in a country is a function of the degree of commitment felt by the government to the protection of its people'....''
Eric Alley, Emergency (UK, Autumn, 1993)
A NY Times report (9/26/93) quoted Victor Mikhailov, head of the Russian Ministry of Atomic Energy, as saying that Moscow's nuclear arsenal peaked at 45,000 warheads, exceeding all estimates save those of the most hawkish analysts. Addition-ally, he said that the Russian stockpile of enriched uranium is more than 1,200 metric tons, more than twice as large as commonly believed. The uncertainty in our estimate of the Russian stockpile is as large as the entire US stockpile.
``The large numbers lead you to worry that some of the planners may have had a first strike in mind,'' stated Admiral Bobby Ray Inman, former NSA Head.
The Federal Emergency Management Agency failed to include any radiological defense (RADEF) funding in its 1994 budget, and Congress made no effort to restore this funding (Grant Taylor, former RDO for Vermont).