MOST AUSTRALIANS remember that
the Black Saturday bushfires in Victoria
in 2009 killed 173 people. But the
crippling heat wave that came
alongside them killed more than twice
that number: 374 people. The 2003
European heat wave killed 50,000–
70,000 people, while the Russian heat
wave of 2010 killed about 55,000.
The World Meteoro-
logical Organisation
defines a heat wave as
a period of five days in
a row with a maxi-
mum temperature
5 ºC or more higher
than the average
maximum tempera-
ture for that
location.
It’s difficult to
link specific deaths
to a heat wave, however,because there are few clues that appear
in an autopsy. Furthermore, your ability
to tolerate heat depends on what
temperatures you are used to, your age,
health, fitness, and many other factors.
But morticians easily recognise
heat-wave deaths in the morgue, when
the bodies start to pile up. During the
heat waves listed above and Victoria
again in 2014, there was simply no more
room to store the bodies that
were coming in. The
overflow had to be
stored in mortuaries,
universities and
funeral parlours.
Unfortunately, with
climate change, the
projections are that
future heat waves will
be more extreme in
temperature, happen
more frequently, last longer,and cover more of the Earth’s surface.
Back in the early 1960s, heat waves
with temperatures three standard
deviations above the average covered
about 1 per cent of our planet’s land
area. By 2010 they covered about 5 per
cent. By 2020 it’s expected to rise to 10
per cent – and by 2040, 20 per cent. In
other words, before the middle of this
century, when heat waves do arise,
they will cover about one-fifth of all of
Earth’s land area.
In fact, heat waves have killed
more Australians than all other natural
disasters combined. At least 4500
Australians have died from heat waves
since the year 1900. For the vulnerable
at least, heat packs a powerful punch.with Dr Karl Kruszelnicki
Heat wave
NEED
TO KNOW
DR KARL is a University of Sydney physicist and
a prolifi c broadcaster and author. His new book,
Dr Karl’s Short Back and Science, is published by
Pan Macmillan. Follow him on Twitter: @DoctorKarl.buzz
22 Australian GeographicTOP: BRENDON THORNE / GETTY; KOALA: WILLIAM WEST / GETTY /Phascolarctos cinereusDR KARL BEN HANSENAlthough
koalas can
spend up to
20 hours a
day sleeping
or resting, it’s
not because
they have
become intoxi-
cated by gum leaves.
Their sleepy behaviour is
instead a means to conserve
energy. Gum leaves are aAsk an expert
Do koalas get intoxicated
by their diet of gum
leaves?Dr Karen Ford, animal physiology
and behaviour expert, Australian
National University, Canberra.Q
A
poor source of energy, and koalas only
obtain about as much energy from their
diet every day as we’d get from eating
five slices of bread. As well as being
a poor source of nutrients, eucalypt
leaves contain many toxic compounds.
Koalas, however, are efficient at
metabolising these, and can exploit a
food resource not available to
most animals. There are,
however, other animals
known to be adversely
affected by food
choices. Tasmanian
poppy growers have
reported wallabies
behaving strangely in
their fields; and ‘drunken
parrot season’ in the NT
produces dozens of seemingly
drunk red-collared lorikeets each year,
although experts aren’t entirely sure
what accounts for the symptoms.January 2016 marks 30
years since AUSTRALIAN
GEOGRAPHIC was first
published. To celebrate,
veteran AG photographer
and musician Barry Skipsey
(see page 93) recorded a
special song, called When
Australian Geographic Took
The Stage. To watch the
video use the free viewa
app to scan this page.Happy Birthday to us!