8.3.8. Human Settlements and Industry
Housing, industry, commerce, and the major components of infrastructure that
support settlements-energy, water supply, transportation, waste disposal, and
so forth-have varying degrees of vulnerability to climate change. They can be
affected directly through projected changes in climate (temperature, precipitation,
etc.) and indirectly through projected impacts on the environment, natural resources,
and agriculture. Indirect pathways to impacts include expected changes in the
availability of natural resources, geographic shifts in climate-sensitive resource
industries, effects on environmental quality and health from changes in ecosystems,
and other effects resulting from changes in environmental service functions.
Furthermore, these effects on human settlements in theory could lead to tertiary
impacts-such as altering land use and redistributing population and activities
to other regions-resulting in further changes in natural resources and other
activities. Such effects, however, are largely speculative at the current state
Climate directly affects the quality of life; alters patterns of settlement
and human activities; subjects humans to risks to their health, safety, and
property (e.g., due to extreme events); and, therefore, has costs and benefits
for individuals and for the private and public sectors. As such, changes in
climate are expected to have positive and negative impacts.
Climate change will have direct impacts on economic activity in the industry,
energy, and transportation sectors; impacts on markets for goods and services;
and impacts on natural resources on which economic activity depends. Activities
directly sensitive to climate include construction, transportation, offshore
oil and gas production, manufacturing dependent on water, tourism and recreation,
and industry that is located in coastal zones and permafrost regions. Activities
with markets sensitive to climate include electricity and fossil fuel production
for space heating and air conditioning, construction activity associated with
coastal defenses, and transportation. Activities dependent on climate-sensitive
resources include agro-industries (food/drink, forestry-related activity, and
textiles), biomass production, and other renewable energy production.
Impacts occurring in the distant future are difficult to predict in detail
because the context of human settlement patterns and technologies cannot be
forecast accurately. Concomitantly, there are substantial opportunities for
adaptation to changed climates in conjunction with the development of future
housing and infrastructure facilities, depending in part on our capability to
forecast climate changes. Many types of impacts on human facilities have the
potential to be partially or completely reduced or eliminated through adaptation,
though this usually will increase their costs.
220.127.116.11. Impacts on Transportation
Projected changes in climate will have both negative and positive impacts
on the operation and maintenance costs of transportation systems.
Studies in temperate and northern climates generally have indicated that higher
temperatures will result in lower maintenance costs, especially with fewer freeze-thaw
cycles and less snow (e.g., Walker et al., 1989; Daniels et al., 1992). Black
(1990) points out, however, that increased pavement buckling caused by longer
periods of intense heat is a possibility. Lewis (1988) and Hirsch (1988) cite
such cases from the great North American summer heat wave of 1988.
In moderate climates, water transport would be affected by changes in river
navigability. Reductions in rainfall, which are possible during the summer in
mid-latitudes in North America, could adversely affect waterborne transportation.
During the 1988 drought, industries that relied on bulk transportation of raw
materials and finished products by barge on the Mississippi River found that
low water kept more than 800 barges tied up for several months. In 1993, by
contrast, floods in the upper Mississippi valley also disrupted the barge transportation
system, and in 1997 increased siltation associated with floods prevented ships
from reaching the port of New Orleans for several days. To the extent that industry
is moving toward just-in-time production systems, it will become more vulnerable
to interruptions for these and other reasons.
In colder regions, the most significant direct impact of warming is likely
to be on inland and coastal water transportation. A longer season for Arctic
shipping is likely for locations like Prudhoe Bay, Alaska, which depends on
the short ice-free season to barge in modular loads too large to go by truck.
Increased wave activity and increased frequency of extreme weather events might
have a more significant effect on coastal transportation operations, but little
research has been conducted on this topic. A survey of the potential impacts
on Canadian shipping suggested net benefits to Arctic and ocean shipping as
a consequence of deeper drafts in ports and longer navigational seasons (IBI
Winter roads on ice constitute an important part of the transportation network
in parts of Canada's north. For example, about 10-15% of the total annual flow
of goods in the Mackenzie Valley moves over winter roads, some of which cross
major rivers. As the name implies, winter roads (or ice roads) are functional
in the winter only; they are made of snow, ice, or a mixture of soil and snow/ice
and can be created on the frozen surface of lakes and rivers. Lonergan et al.
(1993) found a substantial reduction in the length of the "ice road" season
based on climate change projections.
Further south, there would be a greater number of ice-free days for inland
waterways such as the Great Lakes and St. Lawrence Seaway (IBI Group, 1990).
Inland waterways, however, may suffer loss of depth from greater periods of
seasonal drought, reducing their usefulness for commercial shipping even if
the ice-free season is lengthened (Black, 1990). A similar study showed that
reduced ice cover compensated for lower water levels in two of three climate
change scenarios but that dredging costs generally increased in the six Great
Lakes ports examined (Keith et al., 1989). Other climate impacts could arise
from changes in snowfall or melting of the permafrost (IBI Group, 1990).
Changes in the location and nature of agricultural activities, as well as
other climate-dependent industries, could have a large impact on the freight
Existing assessments of transportation impacts have recognized the potential
significance of changes in geographical patterns of economic activity on the
transportation network. Black (1990) notes that even gradual, long-term global
warming could cause a major disruption of the movement of goods and people in
North America. The IBI Group (1990) suggests that there probably would be a
northward spreading of agricultural, forestry, and mining activities-resulting
in increased population and intensified settlement patterns in Canada's mid-north
and even in Arctic areas. Marine, road, rail, and air links would have to be