[extropy-chat] nuclear spring?

BillK pharos at gmail.com
Tue Dec 12 10:56:08 UTC 2006

On 12/12/06, spike wrote:
> I recall years ago Carl Sagan making the case that if the US and the commies
> nuke each other, the dust particles kicked into the air would increase the
> albedo of the earth and cause a nuclear winter, a new ice age.  But what if
> Iran and Israel go at each other with nukes?  They have only a fraction of
> the numbers Sagan was assuming, so what happens then?
> Is there a relatively small cooling effect that offsets global warming?
> http://news.yahoo.com/s/ap/20061211/ap_on_sc/nuclear_winter
> A grim scenario is this.  Israel has now admitted that they have nukes, and
> the world is standing by as Ahmadinijehad leads Iran into the club.  We can
> see this coming as clearly as if it has already happened: those two guys are
> going to get into it, possibly soon.  Any speculation on which effect is
> greater, a small nuclear winter or global warming?

Remember Carl Sagan makes errors just like everybody else.  :)

The nuclear winter scenario generally assumed that half of the worlds
nuclear weapons would be used, ~5000 Mt, destroying approximately
1,000 cities, and creating large quantities of carbonaceous smoke.

But a small nuclear exchange would not have such severe effects.

The burning of 526 Kuwaiti oil wells during the Persian Gulf War
showed the effects of vast emissions of particulate matter into the
atmosphere in a geographically limited area; directly underneath the
smoke plume constrained model calculations suggested that daytime
temperature may have dropped by ~10°C within ~200 km of the source.

Cornell Professor Carl Sagan, of the TTAPS study, predicted on ABC's
Nightline that the smoky oil fires could cause a worldwide ecological
disaster of black clouds resulting in global cooling. Retired
atmospheric physicist and climate change skeptic Fred Singer dismissed
Sagan's prediction as nonsense, predicting that the smoke would
dissipate in a matter of days. In his book The Demon-Haunted World,
Sagan gave a list of errors he had made (including his predictions
about the effects of the Kuwaiti oil fires) as an example of how
science is a learning process.

A new study, as discussed in the Yahoo news article predicts:
We use a modern climate model and new estimates of smoke generated by
fires in contemporary cities to calculate the response of the climate
system to a regional nuclear war between emerging third world nuclear
powers using 100 Hiroshima-size bombs (less than 0.03% of the
explosive yield of the current global nuclear arsenal) on cities in
the subtropics. We find significant cooling and reductions of
precipitation lasting years, which would impact the global food

So 100 nuclear bombs on *cities* would still have severe effects
lasting for years.

So it depends on how many nuclear bombs (and conventional bombs) the
US plans to use on Iran to destroy their underground nuclear
facilities and ensure their army is no longer a threat.   It must be
very tempting for the military to use nuclear weapons, rather than
have night after night of conventional bombing for a period of months.
(The bombing might be done via Israel, of course, to give the US
plausible deniability).


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