[...]In the next post I'll post a link to the article Randall is quoting. Again, this article was hard to find on the Internet and seems to be incomplete. In fact I could find only one place on the net that has republished it, and probably not all of it.
Found it on two places now, one here and on here. It appears this original is from the year 2000.
I'll reprint the text below, in case it goes missing on the internet. Notice that in the second link above, another text is mentioned at the beginning, where Dr Benny Peiser is quoted. That text is linked back to the original article from "discovery.com", that seems to have been deleted since... You will find that one also reprinted in the second quote below.
Impact Events Shaped Rise Of Civilization
Liverpool - March 7, 2000 -
In a presentation to the Annual Meeting of the American Association for the Advancement of Science (AAAS), Dr Benny Peiser of Liverpool John Moores University, presented new evidence suggesting that more than 500 impact events of extraterrestrial orgin have punctuated Earth during the last 10,000 years.
The great majority (70%) of these events have been of the Tunguska-type class of atmospheric impacts with an average energy yield of between 20 and 100 Mt TNT. However, more than 100 surface impacts, including more than a dozen oceanic impacts, are believed to have repeatedly devasted whole regions, small countries and early civilisations around the globe.
In a worst case estimate, Dr Peiser said that up to eight climatic downturns detectable in the geological and climatological records of the Holocene may be directly associated with multiple impact events.
"Episodes of increased cometary or meteoric activity punctuating societal evolution should be looked upon as potential agencies determining the rise and fall of ancient civilisations.
Both the emergence and the collapse of human cultures, the Pleistocene-Holocene transition and the Neolithic Revolution, the onset and collapse of the Bronze Age civilisations, and even the collapse of the Roman Empire may be associated with episodes of increased cosmic activity and multiple impacts that may well have included incidents of cosmic dust loading."
While most of these impacts occurred over unpopulated areas of the globe, there are historical accounts about devastating cosmic catastrophes. According to a number of Chinese records, about 10,000 people were killed in the city of Chi'ing-yang in 1490 AD due to the break-up of a small asteroid.
About a dozen hypervelocity impact craters that date from the Holocene period (i.e. since the end of the ice age) have been discovered to date. The majority of impacts, however, that occurred during this crucial period of societal evolution have not been detected yet.
According to Dr Peiser, "the 14 known Holocene impact craters most certainly paint a rather deceptive picture of our past. The fact that no massive impact crater dating to the Holocene has been detected, has led to the belief that no hemispheric or global impact disaster can possibly have happened. However, this is a widespread delusion."
Yet there still is a regretable lack of interest by the scientific community to scrutinise the Holocene for major impact events.
"The widespread ignorance of such cosmic disasters in historical time is due to the limited research focus on crater producing events. Yet only 3% of fatal impacts produce a hypervelocity surface crater on land", Dr Peiser points out.
Tunguska-like impacts or "Super-Tunguskas" are thus taken out of the equation. Due to their catastrophic detonation above ground (or in the oceans), they often leave no obvious fingerprints behind.
Dr Peiser also presented new impact simulations that estimate expected fatalities of cosmic impacts for the next 10,000 years. Without the establishment of effective strategies of planetary defense in the future, more than 13 million people are expected to die as a direct result of impact catastrophes in the next ten millennia.
"We can, and indeed have to live with smaller, Tunguska-type impacts. There is little we can do about them. But we need to prevent the impact of larger objects which threaten the stability of our civilisation.
"Unless we start planning ahead and develop the technology for the deflection of this threat, cosmic impacts will inevitably lead to major disasters in the future", Dr Peiser stressed.
Based on computer simulations that take into account the current flux of near-Earth objects, a typical 10,000 years period with a constant human population of 5 billion can expect to experience: *110 fatal impacts resulting in a total of 13 million fatalities (an average of 120,000 fatalities per event).
"These estimates are based on the assumption that the current asteroidal and cometary flux will be constant in time and quantity over the next 10,000 years. However, there is growing evidence to suggest that there have been peak levels of meteoritic activity in the past that differed significantly from the cosmic calm of the last 300 years", Dr. Peiser pointed out.
- 300 "Tunguska" style airbursts over land, with 80 of these producing fatalities (roughly 1 fatal event per century).
- 12 ocean impacts that produce tsunami, with an average of 500,000 fatalities per event.
- 4 land impacts, with an average of 500,000 fatalities per event.
In January, a UK Task Force was set up by Lord Sainsbury, the Science Minister, to look into the way in which Britain should respond to the impact hazard and how it can contribute to the international efforts prevent major impacts from happening in the future.
ASTEROID IMPACTS SHAPED HISTORY?
From DISCOVERY.COM, 23 February 2000
http://www.discovery.com/news/briefs/20000223/space_impacts.html
The role of the multi-megaton impacts of comets and asteroids could be
very significant, says Benny Peiser, a social scientist from Liverpool
John Moores University in England.
"The focus over the years has been the big events," Peiser says,
referring to the alleged global catastrophe that followed the impact of
an asteroid with the Earth 65 million years ago -- wiping out the
dinosaurs.
But smaller events similar in size to the 1908 Tunguska blast that is
believed to have leveled 2000 square miles of forest could play a big
role in history, Peiser explained to scientists on Saturday at the
meeting of American Association for the Advancement of Science in
Washington, D.C.
The Tunguska event left no crater because the lightweight comet or
asteroid exploded in the atmosphere before reaching the ground,
scientists believe.
Similar extraterrestrial blasts in history might have triggered the
demise of Bronze Age civilizations in the Mediterranean, account for the
mysterious disappearance of certain cultures in the Americas, and
explain the rise of apocalyptic religions and biblical references to
localized disasters, says Peiser.
It also would mean that we are more vulnerable to such disasters than
currently thought.
"We haven't got any indication of when another asteroid might come
close," says Peiser.
Astronomers, however, are skeptical of Peiser's danger assessment.
"I can't say it's never happened," says asteroid impact specialist
Richard Binzel of the Massachusetts Institute of Technology, regarding
the possibility of a Tunguska-sized event hitting a populated area. "But
on the entire surface of the Earth the area of destruction is very
small."
In other words, the chances are tiny, and were downright miniscule when
there were fewer people and fewer cities.
As for the odds of another global catastrophe like the one that
supposedly killed the dinosaurs, says Binzel, there's a one in 10,000
chance of it happening in any given century.
"We're just more conservative" in danger estimates, Binzel says.
Copyright 2000, Discovery.com
