3.6. Human Settlements, Energy, and Industry
A growing and increasingly quantitative literature shows that human settlements
are affected by climate change in one of three major ways:
- The economic sectors that support the settlement are affected because of
changes in resource productivity or changes in market demand for the goods
and services produced there. [4.5]
- Some aspects of physical infrastructure (including energy transmission and
distribution systems), buildings, urban services (including transportation
systems), and specific industries (such as agroindustry, tourism, and construction)
may be directly affected. [4.5]
- Populations may be directly affected through extreme weather, changes in
health status, or migration. The problems are somewhat different in the largest
(<1 million) and mid- to small-sized population centers. [4.5]
The most widespread direct risk to human settlements from climate change is
flooding and landslides, driven by projected increases in rainfall intensity
and, in coastal areas, sea-level rise. Riverine and coastal settlements are
particularly at risk (high confidence6),
but urban flooding could be a problem anywhere that storm drains, water supply,
and waste management systems have inadequate capacity. In such areas, squatter
and other informal urban settlements with high population density, poor shelter,
little or no access to resources such as safe water and public health services,
and low adaptive capacity are highly vulnerable. Human settlements currently
experience other significant environmental problems which could be exacerbated
under higher temperature/increased precipitation regimes, including water and
energy resources and infrastructure, waste treatment, and transportation [4.5]
Rapid urbanization in low-lying coastal areas of both the developing and developed
world is greatly increasing population densities and the value of human-made
assets exposed to coastal climatic extremes such as tropical cyclones. Model-based
projections of the mean annual number of people who would be flooded by coastal
storm surges increase several fold (by 75 to 200 million people depending on
adaptive responses) for mid-range scenarios of a 40-cm sea-level rise by the
2080s relative to scenarios with no sea-level rise. Potential damages to infrastructure
in coastal areas from sea-level rise have been projected to be tens of billions
US$ for individual countries -- for example, Egypt, Poland, and Vietnam. [4.5]
Settlements with little economic diversification and where a high percentage
of incomes derive from climate-sensitive primary resource industries (agriculture,
forestry, and fisheries) are more vulnerable than more diversified settlements
(high confidence6).
In developed areas of the Arctic, and where the permafrost is ice-rich, special
attention will be required to mitigate the detrimental impacts of thawing, such
as severe damage to buildings and transport infrastructure (very high confidence6).
Industrial, transportation, and commercial infrastructure is generally vulnerable
to the same hazards as settlement infrastructure. Energy demand is expected
to increase for space cooling and decrease for space heating, but the net effect
is scenario- and location-dependent. Some energy production and distribution
systems may experience adverse impacts that would reduce supplies or system
reliability while other energy systems may benefit. [4.5
and 5.7]
Possible adaptation options involve the planning of settlements and their infrastructure,
placement of industrial facilities, and making similar long-lived decisions
in a manner to reduce the adverse effects of events that are of low (but increasing)
probability and high (and perhaps rising) consequences. [4.5]
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