Then we come to one of Rama's posts.
As part of his objection to the nuclear winter case cited by Alteran, Rama cited Mike Wong's NW part from his BDZ page.
Wong's estimates are in excess of what is needed, by several orders of magnitude, from the moment you spread the damage.
That's not far from WolfRitter (General Schatten at SBC) who claimed on these boards that tens of millions of megatons would be needed to collapse a civilization.
But let's see what Wong said:
Other than the facts that SW civs use lots of variants of plastics and that turbolasers were noted to leave radioactive elements on targeted areas, the major problem with this text is that it largely deals with a single impact, a totally localized impact.Mike Wong wrote: Some casual observers assume that a nuclear winter is an "on/off" scenario, ie- you either don't get a nuclear winter and the biosystem survives, or you get a nuclear winter and the entire biosystem dies. That is not the case. Only the most extreme and devastating nuclear winter scenario would result in the extermination of all advanced forms of life on a planetary scale.
Computer simulations of large-yield asteroid impacts (a worst-case scenario for atmospheric particle ejection) show that global climate changes occur with yields of 1E5 megatons and above. Such simulations have shown that an impact of 3E5 megatons would create nuclear winter effects leading to the deaths of more than 25% of the Earth's human population.
http://www.lpi.usra.edu/books/AsteroidsIII/pdf/3043.pdf
This would be devastating for any planetary civilization, but with a 75% survival rate, it is completely inadequate for a Base Delta Zero operation.
From the same source, mass extinction events are projected to occur with yields of 10 million megatons and above. The so-called "Dino-killer" asteroid struck the Earth 65 million years ago with approximately 100 million megatons yield, creating a 200 km wide crater and hurling some 1E16 kg of dust into the atmosphere. This darkened the atmosphere, dramatically lowering global temperatures and triggering a mass-extinction event in which some three quarters of the Earth's living species were wiped out. However, even this kind of global catastrophe is not comparable to a BDZ. The biosystem did survive (obviously, since we are here), and a BDZ does not allow for one quarter of a planet's species to survive (even without technological means of environmental protection, such as humans would have).
Global catastrophes severe enough to threaten the survival of all advanced forms of life (ie- what we generally consider "sentient life forms", as opposed to bacteria and insects) occur with yields of 1 billion megatons and above (4E24 J). This is somewhat larger than the BDZ energy yield estimate (2E24 J). Keep in mind, however, that even such a global catastrophe still relies largely upon long-term environmental effects, while a BDZ operation exterminates all forms of animal and plant life, including humans in artificial shelters or hardened military facilities, in less than a day.
One might argue that these figures are not directly applicable to a BDZ operation, which would presumably involve a widely dispersed attack rather than a localized attack. However, the amount of dust and soot thrown into the atmosphere would be the same. The significant differences between asteroid impacts and nuclear war are the widespread multiple shockwave centres of nuclear war (tidal wave and shockwave are regional in a high-energy asteroid impact), the selective targeting of nuclear explosions (which obviously increases the human casualty rate dramatically), and the effects of radioactive fallout and smoke from the burning of man-made materials such as plastics and petroleum products in major cities (which obviously didn't exist during ancient asteroid impacts). Keep in mind that burn effects (as opposed to blast shockwaves) are global in both scenarios; the K-T mass-extinction asteroid impact was so violent that it most likely ignited fires all over the entire planet.
http://www.agu.org/journals/ABS/1997/96RG03038.shtml
However, these are long-term indirect environmental effects, and inapplicable to BDZ. Moreover, a BDZ will not involve the kind of radioactive fallout produced by thermonuclear weapons, and it is highly doubtful that the Star Wars civilization relies as heavily upon petroleum products as we do today.
Clearly, not only are long-term environmental "nuclear winter" effects inapplicable to a BDZ operation because of its short timeframe, but even if a BDZ exclusively employed groundbursts in order to apply the maximum possible energy to the creation of atmospheric soot and dust, the energy requirement for global extermination of sentient life would still remain at its current level or above. In this scenario, not only would blast/burn effects be reduced (because of diminished efficiency in propagation of both effects from ground bursts as opposed to air bursts), but the largely environmental effects would lengthen the depopulation timeframe from hours to weeks or months, which is obviously well beyond the parameters of a BDZ. Moreover, they would be ineffective against hardened military targets or even civilian bomb shelters, both of which could easily preserve survivors long enough for rescue and evacuation.
Now, the following document's second half shows that 100 15 Kt nukes spread over half of the Earth's surface, in the case of a full scale war, would produce dramatic effects, described thusly:
That's about 1.5 MT spread across half the planet. Multiply that by two, and you obviously double the casualties, therefore logically reaching a near complete extermination of the human population.Studies of the consequences of full-scale
nuclear war show that indirect effects of the
war could cause more casualties than direct
ones, perhaps eliminating the majority of the
world’s population (11, 12). Indirect effects
such as damage to transportation, energy,
medical, political, and social infrastructure
could be limited to the combatant nations in
a regional war. However, climate anomalies
would threaten the world outside the combat
zone. The predicted smoke emissions and
fatalities per kiloton of explosive yield are
roughly 100 times those expected from estimates
for full-scale nuclear attacks with
high-yield weapons. (4)
If you take the usual way hammies conflate all lines from Caves of Ice, we see that they claim the ships would sterilize an entire continent, and that would leave the planet uninhabitable for generations.
We can already guess that several barrages of kiloton lances all over a continent -in a way more thorough that in the PDF I linked to (first posted here by JMS)- would easily provide all the elements needed to completely stick the planet into a large nuclear winter, as the amount of particles released in this fashion would largely surpass anything that would burn as an aftermath of 100 15kt bombs dropped on urban centers.
There's also the fact that the planet itself is already very hostile. According to Cain:
Caves of Ice wrote:WARP KNOWS I’VE seen more than my fair share of Emperor forsaken
hell-holes in more than a century of occasionally
faithful and dedicated service to the Imperium, but the ice world
of Simia Orichalcae1 stands out in my memory as one
of exceptional unpleasantness. And when you bear in mind
that over the years I’ve seen the inside of an eldar reaver
citadel and a necron tomb world, just to pick out a couple of
the highlights (so to speak), you can be sure that my
experiences there rank among the most terrifying and life threatening
in a career positively littered with hairs’-breadth
escapes from almost certain death.
Caves of Ice wrote:I could readily understand why: the Guard sent its regiments
wherever they were needed, and the Valhallans rarely got the
chance to fight in an environment where they felt completely
at home. Simia Orichalcae was probably the closest thing to
their homeworld either officer had seen since they joined up,
and I could sense their impatience to get down there and feel
the permafrost beneath their boot soles.
Now if you wonder what Valhalla is all about, you can check it out here. That's like Hoth. Now add a fair amount of particles that prevent the sun from ever heating up the ground.Caves of Ice wrote:Durant swept the hololith
display round to the west, skimming us across the surface of
the barren world with breathtaking speed. The broken
landscape of the mountain range swept past, the higher peaks
dotted with scrub, lichen, and a few insanely tenacious trees -
apparently the only vegetation which could survive here. Just
as well too, or there wouldn’t be an atmosphere you could
breathe. Beyond the foothills was a broad plain, crisp with
snow, and for a moment I could understand the affection my
colleagues had for this desolate but majestic landscape.
It goes without saying that it would take little to render the atmosphere particularly hard to breathe in such conditions.
All in all, it's quite fantastic how they're willing to be dead literal about Cain's words in his archives, yet suddenly become very lax about the meaning of barrages.