Global Report on Human Settlements 2007 - PoA-ISS

186
Natural and human-made disasters
Climate change has
far reaching consequences
for the
incidence and
impacts of disasters
in cities
… if sea levels rise
by just one metre,
many coastal mega
cities with populations
of more than
10 million people …
will be under threat
Slums are characterized
by inadequate
and insecure living
conditions that
generate hazard…
tating fires. In São Paulo in 1974, 189 people died in a fire in
a 25-storey building. 66 The close proximity of residential,
commercial and industrial land uses in a city can generate
new cocktails of hazard that require multi-risk management.
Calcutta and Baroda are just two cities where the close
proximity of manufacturing, hazardous materials storage and
residential areas has been a cause for concern. 67 The growth
of slums whose residents’ livelihoods are tied to solid waste
dumps is a similarly common cause of hazard in large cities
such as Manila, where 300 people were killed by a landslide
in the city’s Patayas dump. 68
■ The impact of climate change
Climate change has far reaching consequences for the
incidence and impacts of disasters in cities. Cities are particularly
vulnerable to the impacts of climate change, as this is
where much of the population growth over the next two
decades will take place and where a large and growing
proportion of those most at risk from climate change
reside. 69
Rising global temperatures and the resultant changes
in weather patterns and sea levels have direct impacts on
cities. In particular, cities located along the world’s coastlines
will face an increased number of extreme weather
events such as tropical cyclones, flooding and heat waves. 70
There has been a 50 per cent rise in extreme weather events
associated with climate change from the 1950s to the
1990s, and the location of major urban centres in coastal
areas exposed to hydro-meteorological hazards is a significant
risk factor: 21 of the 33 cities which are projected to
have a population of 8 million or more by 2015 are located in
vulnerable coastal zones and are increasingly vulnerable to
sea-level rise. 71 Around 40 per cent of the world’s population
lives less than 100 kilometres from the coast, within
reach of severe coastal storms. In effect, close to 100 million
people around the world live less than 1 metre above sea
level. Furthermore, recent research shows that 13 per cent
of the world’s urban population lives in low elevation coastal
zones, defined as less than 10 meters above sea level. 72
Thus, if sea levels rise by just 1 metre, many coastal
megacities with populations of more than 10 million people,
such as Rio de Janeiro, New York, Mumbai, Dhaka, Tokyo,
Lagos and Cairo will be under threat. Indeed, several projections
have indicated that sea levels are expected to rise by 8
to 88 centimetres during the 21st century due to climate
change. 73
Climate change also has less dramatic and direct
effects on cities. In sub-Saharan Africa, climate change and
the consequent extreme climatic variations is a key factor
which causes rural populations to migrate to urban areas,
thereby fuelling rapid and often uncontrolled urban
growth. 74 In turn, this exacerbates other disaster risk factors
such as the spread of settlements into easily accessible yet
hazardous locations and unsafe building practices.
While cities remain vulnerable to the effects of
climate change, they are also key contributors to global
warming. Cities are responsible for 80 per cent of the carbon
emissions that cause climate change through energy generation,
vehicles, industry and the burning of fossil fuels and
biomass in household and industrial energy consumption. 75
Levels of greenhouse gas emissions are higher in many cities
of developed countries than in developing country cities. For
instance, emissions from cities in North America and
Australia are often 25 to 30 times higher than those of cities
in low-income countries. 76
■ The vulnerability of urban slums
Some 998 million people lived in urban slums in 2006, and if
current trends continue, it is predicted that some 1.4 billion
will live in slums by 2020. 77 It is not unusual for the majority
of urban residents in cities to be excluded from the formal
housing market. In Manila, informal settlements at risk to
coastal flooding make up 35 per cent of the population; in
Bogota, 60 per cent of the population live on steep slopes
subject to landslides; and in Calcutta, 66 per cent of the
population live in squatter settlements at risk from flooding
and cyclones. 78
Slums are characterized by inadequate and insecure
living conditions that generate hazard; but they are also
home to many people with few resources and, thus, high
vulnerability. At an individual and household level, vulnerability
to natural and human-made hazard is shaped by the
kinds of physical, economic, social and human capital assets
that people can command. Capacity to increase, protect or
diversify an asset profile is largely determined by cultural,
administrative and legal institutions and opportunities, such
as security of tenure, access to markets, customary hospitality
or the effectiveness of the rule of law. Many people in
slums have fewer assets and supporting institutions than
those living in formalized residential areas and are consequently
highly vulnerable to harm from natural and
human-made hazards, as well as from other risks associated
with crime, violence and insecurity of tenure. Box 7.10
describes such risk conditions for those living in one of Rio
de Janerio’s slums.
The most important physical asset for the urban poor
is housing. Housing provides personal security, but can also
be a livelihood resource if it is the locus of home-based
enterprises. Those with no home at all are perhaps the most
vulnerable. During Hurricane Mitch in 1998, a disproportionate
number of the victims were street children. 79 For
those with homes, lack of secure tenure has many consequences
for their quality of life. 80
Lack of secure tenure, discussed in greater detail in
Part III of this <strong>Global</strong> <strong>Report</strong>, reduces people’s willingness to
upgrade and therefore mitigate local environmental hazard.
Renters as well as those living in squatter settlements are at
risk from eviction, generating uncertainty before disaster
and often resulting in homelessness post-disaster due to
competing higher-value land uses. It is not unusual for disasters
to be followed by the redevelopment of inner-city
low-income rental or squatter areas during reconstruction,
often (and famously, in the case of Mexico City) with
widespread protest.
When people are excluded from the formal housing
market through poverty, they are forced to live in places of
risk. People often choose to face environmental hazards and
increase their chances of earning a living than live in a more