Just Hear Me Out: "Would Nuclear Winter Cancel Out Global Warming?"
From Hackaday, January 25:
Nuclear war was very much a front-of-mind issue during the fraught
political climate of the Cold War era. Since then, atomic sabre rattling
has been less frequent, though has never quite disappeared entirely.
Outside of the direct annihilation caused by nuclear war, however, is
the threat of nuclear winter. The basic concept is simple: in the
aftermath of a major nuclear war, the resulting atmospheric effects
could lead to a rapid cooling in global temperatures.
Some say it couldn’t ever happen, while others – including Futurama – suggest with varying degrees of humor that it could help cancel out the effects of global warming. But what is the truth?
Hard data is isn’t really available, as thus far there have been no
large-scale nuclear wars for scientists to measure. Several studies have
explored the concept of nuclear winter, however, and explored its
potential effects.
How Does It Work, Anyway?
Hundreds
of large firestorms triggered by nuclear weapons could loft soot into
the upper atmosphere, serving as the causative mechanism of the “nuclear
winter” theory. The nuclear aspect is only as an ignition source; any
other cause of widespread firestorms could do the same. Image Credit: Public Domain, Jim Peaco
The basic concept of nuclear winter is simple. In a large nuclear
conflict, where nuclear weapons are used in strategic strikes against
urban and industrial areas, large-scale fires would rage out of control.
These fires would then loft large amounts of black carbon soot into the
upper reaches of the atmosphere. Once there, the smoke particles might
then be lofted further up into the stratosphere as they absorb heat from
the sun, up to a point where the particles are too high to be quickly
“rained out” of the air by precipitation. These particles would then
essentially shade the surface, creating a cooling effect.
Papers published as recently as 2007
suggests that a full-scale nuclear war between superpowers could cause a
drop in global average temperatures by as much as 8 °C . If that
doesn’t sound dramatic, to put it into perspective the average
temperature was 5 °C lower during the last ice age 18,000 years ago.
Modelling from researchers on the topic suggests that the major knock on effect on agriculture
would be crippling to humanity around the globe. Temperatures in
critical growing regions in Ukraine and Iowa, for example, could see
daily minimum temperatures reach below freezing for several years,
making growing food crops near-impossible. Global famine would be the
result.
This
photo is often mistaken for being a shot of the mushroom cloud created
by the nuclear bomb dropped on Hiroshima in 1945. However, it is in fact
an image of the pyrocumulus cloud created in the firestorm that
happened in the aftermath of the attack. Image credit: Public domain, US Military
Running simulations with newer climate models has continued to turn up similar results, even in recent studies.
Those studies are run with similar base numbers that suggest an all-out
nuclear war using up most of the stockpiles of major superpowers would
loft around 150 teragrams of soot into the atmopshere. However, that
value remains an assumption that has drawn criticism from some sectors.....
