The Impact of Climate Change on Natural Disasters - Reducing Disaster: Early Warning Systems for Climate Change - page 25

age, will not infl uence the occurrence of climate extremes but they can impact the
way populations are able to prepare for, withstand, and recover from the impacts
(IPCC 2012a ).
For example, as explained in Sen's ( 1981 ) widely cited topic about the connec-
tion between poverty and famine, drought is not the only cause of a disastrous famine.
Precipitation decrease may be a contributing factor but prevailing factors such as
poverty and the system behind food exchange are dominating. The focus should lie
on exchange entitlement and not on declining food availability (Sen 1981 ). A recent
study by the Chatham House ( 2013 ) about managing famine risk also points out that
a major problem with droughts is that the early warnings are not followed by ade-
quate actions to prevent a disastrous famine. The barriers are usually from political,
institutional, and organizational nature (Chatham House 2013 ).
Another example that demonstrates how natural hazards can turn into disasters is
the Hurricane Katrina that devastated New Orleans in 2005. The hurricane itself
was considered a natural hazard, the fl ooding of the ninth ward (a neighborhood of
New Orleans) however led to a disaster but arguably not a natural disaster. The
disastrous outcome was caused by both: the natural hazard (the hurricane) and
human-made factors such as the inadequate preparedness level (e.g., levees) or
existing differential social vulnerabilities (Cutter and Emrich 2006 ).
In other words, prevailing factors like these mentioned in regard with famine or
Hurricane Katrina can contribute to explain the severity of the impact of a natural
hazard. A natural hazard like a landslide in a deserted mountainous region is hence
not a natural disaster as it is lacking the human involvement. Based on these defi ni-
tions of hazards and disasters, disaster risk is a function of the prevailing conditions
(exposure and vulnerability) as well as the extreme event itself (UNISDR 2011a ) .
The concept of human vulnerability will be further discussed in Chap. 5 .

2.1.2 Categories of Natural Hazards and Problems

with Defi nitions

Natural hazards can be further categorized into sudden- and slow-onset “creeping”
threats (UNEP 2012a ). Sudden-onset hazards are, for example, geological hazards
(e.g., earthquakes, mudslides) and hydrometeorological hazards (e.g., fl oods, except
droughts). Slow-onset hazards are droughts, coastal erosion, and poor air quality,
among others (UNEP 2012a ).
Slow- and sudden-onset hazards can cause temporary as well as long-lasting
disruption to the environment as well as the societies. For example, slow-onset
threats like droughts have wide reaching impacts. The most visible impact of
droughts is the effect on agriculture. Within the agriculture sector, poor rural farm-
ers dependent on rain-fed subsistence agriculture are specifi cally affected (UNISDR
2011a ). However, problems in the agriculture sector then cascade into the economic
and social sectors (e.g., famine) and can last beyond the duration of a drought
(UNISDR 2011a ). Similarly with sudden-onset hazards, the destructive force and