Geoscience Reference
In-Depth Information
Heat waves and droughts
As global temperatures increase, heat waves will increase. As precipitation becomes more
variable and concentrated into more intense rainfall events, so drought will increase. Heat
waves and droughts, however, are relative terms, as it depends where they occur and if a re-
gion already has adaptations in place. For example heat-related death in London start at
23°C, while in Athens deaths start at 26°C. Like storms and floods, heat waves and
droughts are major killers. The 2003 heat wave in Europe killed an estimated 70,000
people. Hardest hit was France with 14,800 deaths in the first three weeks of August and
deaths in Paris increasing by 140 per cent. The people who die in heat waves are usually
the elderly—medics call this 'harvesting', as these people were taken earlier than they
would have normally died. The element that tends to kill the elderly is sustained night-time
temperatures because when asleep they are unable to regulate their body temperature. After
the 2003 heat wave it was realized that many of these deaths were due to the very weak
public health response in France. As a result there were wide-sweeping policy changes in-
cluding monitoring temperatures nationally to better predict heat waves and aid emergency
preparations, improved building design and air conditioning for hospitals and retirement
homes, increased training for health professionals, an emphasis on responsible media cov-
erage with health recommendations regularly broadcast, and planned regular visits to the
most vulnerable members of the population. A second heat wave occurred in 2006, and
these new policies have been shown to have prevented 4,500 deaths. One of the reasons it
is so difficult to understand the impacts of climate change is because people and societies
can adapt to new conditions very quickly.
Figure 23
shows the 2003 European heat wave in
the context of summer temperatures over the last 100 years and those predicted for the next
100 years. What is clear is that the temperature of the 2003 heat wave could be the average
summer temperature in 2050.
Droughts are also a major killer that should be considered. A drought happens when an
area undergoes a prolonged period without sufficient water supply, whether surface or un-
derground water. A drought can last for months or years and is usually caused when an area
receives consistently below average rainfall. Droughts have a substantial impact on the loc-
al ecosystem and agriculture, including drops in crops growth and yield and loss of live-
stock. Although droughts can persist for several years, even a short, intense drought can
cause significant damage and harm to the local economy. Prolonged drought has caused
cause famine, mass migrations, and humanitarian crises. From a disease point of view,
droughts are much worse than floods because of a lack of fresh drinking water, and stag-
nant pools of water. One of the major concerns with climate change is that areas vulnerable
