chapter - Atmospheric and Oceanic Science

puts in risk large number of persons and physical assets of great value.
Nevertheless, the risk is reduced if there are also economies of great scale and
access to services together with an infrastructure well administered. When the latter
factors combine with prevention measures, risks derived from climatic change
can diminish considerably.
People can be directly affected by extreme climate events, causing health damage,
or even migrations. The climatic extreme episodes can modify the rates of
death, injuries or diseases. For example, the health condition can improve as result
of less exposure to cold, or deteriorate as result of a major stress due to heat waves.
The displacements of population caused by climate changes can affect the size and
the characteristics of the population of the urban settlements, which in turn modifies
the demand of services. The problems are slightly different in the biggest cities (for
example, those of more than one million inhabitants) that in small villages. It is more
likely than the first ones be places of final establishment for immigrants from rural
zones or smaller settlements or even from other countries. In the poor settlements
that surround major and middle size cities in development continue there are several
dangers for both health and environment that might be enhanced by global warming.
Nevertheless, big cities have in general a greater influence on national
resources, and therefore, smaller settlements can actually be the more vulnerable.
To reduce social vulnerability to water resource stresses driven by Climate
Change (floods and droughts) it is required the action of a wide range of stakeholders,
including city administrators, community organizations, planners, farming and
health sectors and disaster managers, as well as representatives and institutions of
the water sector. A very important element in this adaptation process is climate
information.
8.2. Main problems
8.2.1. Floods
The main services and problems of water resource
From the effects produced by floods, arises the perception of risk, which in
turn is composed by a social environmental dimension (vulnerability) and a hydrological
dimension (natural threat). According with the frequency, duration and
intensity with which this phenomenon takes place, impacts in a certain area, with a
dynamic boundary of effects in both natural and not natural habitats. Their characteristic
in time is the recurrence and those of severe and extreme magnitude leave
their marks in the geomorphology.
According with data compiled by Munich Reinsurance, there was a peak
record of natural disasters at a worldwide scale between 1997 and 1998. Damages
caused by climatic events amounted to U$S 92 trillions and 32000 dead people.
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