Understanding global security - Peter Hough

NATURAL THREATS TO SECURITY
Table 8.3 The Torino Scale a
0 Events having no likely Collision will not happen
consequence
1 Events meriting careful monitoring Collision is extremely unlikely
2 Collision is very unlikely
3 Events meriting concern 1% chance of localized destruction
4 1% chance of regional destruction
5 Significant threat of regional devastation
6 Threatening events Significant threat of global catastrophe
7 Extremely significant threat of global
catastrophe
8 Certain collisions Localized destruction (occur every 50–1000
years)
9 Regional destruction (occur every
1000–100 000 years)
10 Capable of causing global climate
catastrophe (occur less than once per
100 000 years)
Note: a This scale was devised by Professor Richard Binzel.
measures have been taken to improve the capacity to predict if such a collision
could occur and to initiate thinking on how it could be avoided. The ‘Torino Scale’
has been devised to rationalize the likelihood of asteroid collision (Peiser 2001) (see
Table 8.3).
There are no validated records of human deaths due to NEO collisions but
there is evidence that such collisions have occurred. Meteoroids regularly enter
the earth’s atmosphere (what are referred to as meteors), where most burn up and
disappear, but some survive long enough to strike the surface (meteorites) or explode
close to the surface (bolides). Evidence that comets can collide with planets was
provided in 1994 when Shoemaker-Levy 9 was observed crashing into Jupiter. The
‘Cretaceous/Tertiary Impact’, caused by either a comet or an asteroid, 65 million
years ago created the 250 km wide Chicxulub crater in the Gulf of Mexico and is
widely held responsible for the extinction of the dinosaurs and various other life
forms. A bolide was believed to be responsible for the 1908 phenomenon around the
River Tunguska in Siberia when over 1000 square kilometres of uninhabited forest
were flattened (Chyba et al. 1993).
The rise of human vulnerability to nature
Natural disasters are, of course, as old as humankind. Even older, if the risk posed
to other animals from natural events, such as the fate that befell the dinosaurs, is
considered. However, the frequency and deadliness of natural disasters has increased
in recent years. A number of factors have contributed to this:
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