Environmental Engineering Reference
In-Depth Information
supplies in regions or countries that are affected by com-
bat or subjected to prolonged bombing. Given these
realities, it is inexplicable that wars have received so little
attention as energy phenomena. At the same time, there
is a fairly common perception—greatly reinforced by the
U.S. intervention in Iraq in 2003—that energy is often
the main reason why nations go to war. I address all
these issues.
Weapons are the prime movers of war. They are
designed to inflict damage through a sudden release of
kinetic energy (all handheld weapons, projectiles, explo-
sives) or heat, or a combination both. Nuclear weapons
kill almost instantly by combined blast and thermal radi-
ation, and also cause delayed deaths and sickness due to
exposure to ionizing radiation. All prehistoric, classical,
and early medieval warfare was powered only by human
and animal muscles. The invention of gunpowder—clear
directions for its preparation were published in China in
1040, and the proportions for its mixing eventually set-
tled at 75% saltpeter (KNO
3
), 15% charcoal, and 10%
S—led to a rapid diffusion of initially clumsy front- and
breach-loading rifles and to much more powerful field
and ship guns (Smil 1994). While ordinary combustion
must draw oxygen from the surrounding air, the ignited
KNO
3
provides it internally, and gunpowder undergoes
a rapid expansion to about 3,000 times its volume in
gas. The first true guns were cast in China before the
end of the thirteenth century, and Europe was just a few
decades behind.
Gunpowder raised the destructiveness of weapons and
radically changed the conduct of both land and maritime
battles. When confined and directed in rifle barrels, gun-
powder imparts to bullets kinetic energy 1 OM higher
than that of a heavy arrow shot from a crossbow gun (1
kJ vs. 100 J); the kinetic energy of iron balls fired from
12.7 Kinetic energy of projectiles, from stone-tipped arrows
to heavy gun shells. Plotted from data in Smil (2004c).
cannons was 3 OM higher. Increasingly accurate gunfire
eliminated the defensive value of moats and walls, and
the impact of guns was even greater in maritime engage-
ments (fig. 12.7). Gunned ships equipped with two other
Chinese innovations, compass and rudder, as well as with
better sails, projected empire-building European power
(Cipolla 1966; McNeill 1989). The dominance of these
ships ended only with the introduction of naval steam
engines during the nineteenth century.
The next weapons era began with the formulation of
high explosives prepared by the nitration of such organic
compounds as cellulose, glycerine, phenol, and toluene.
Ascanio Sobrero prepared nitroglycerin in 1846, but its
practical use began only after Alfred Nobel mixed it with
an inert porous substance (diatomaceous earth) to create
