Background - Climate Change and Infrastructure, Urban Systems, and Vulnerabilities - page 16

grow about 50% more rapidly than the national average. Economic activity is not pro-
jected more than one decade into the future; but the clear hope is that - along with total
population growth - the average standard of living will also rise, which translates into a
significant increase in the requirement for supporting infrastructure over the next two to
four decades, much of it in areas of the country at risk from impacts of climate change.
Socioeconomic scenarios being used to frame NCA assessments are based largely
on Bierwagen, 2010, which projects trends in housing density and impervious surface
cover for the United States with reference to the SRES A1, A2, B1, and B2 scenarios. In
the A2 case, which reflects more rapid development, the growth of population and eco-
nomic activity is oriented toward the Southwest, South, and coastal Southeast and East.
In the B1 case, which assumes more moderate development, the growth is more broadly
distributed across the nation. All of the scenarios show major increases in urban and
suburban housing: roughly doubling urban and suburban land area by 2100. Again, the
infrastructure implications are formidable.
2) SECTORAL TRENDS AND CONTEXTS
Similarly, projections of long-term trends in sectors such as energy, transportation,
water supply, wastewater and drainage, and communication infrastructures are either
scarce or unavailable, beyond the world of futures research and proprietary sectoral
forecasts by industry that may not address interdependencies. Most analysts agree that
the national demand for infrastructure services will increase substantially over the next
half-century; the question is whether service demands can be made in innovative ways
that are less physical-structure intensive, associated with such potentials as information-
technology rooted “smart” services and/or dematerialization. One key interaction will
be between technological change - such as in energy and water-use efficiency and in
highway transportation - and infrastructure revitalization, especially in regions and cit-
ies where much of the current infrastructure is aging and overstressed by demand levels
it was not designed to meet. A second key interaction will be between infrastructure re-
vitalization and financial resources. Many infrastructures that are in place half a century
from now will have been installed between now and then; but the process of change im-
plies major financial investments, especially by public sector institutions, in an era when
the public willingness to pay is in question, either through taxation or rate increases.
One key issue is the aging of many built infrastructures in the United States, many
of which date to urban and regional capital investments many decades ago, some more
than a century ago. A recent study by the American Society of Civil Engineers (ASCE,
2011) reports that America's water and wastewater infrastructures are aging and over-
burdened, estimating that the effects of a failure to revitalize these infrastructures are
likely to be dramatic in terms of losses to the national economy. It concludes that cur-
rent spending is only about half of the needed investment, “which means that the U.S.
must invest an additional $1.1 billion over the next five years.” Similar concerns exist for
bridges and other aspects of transportation infrastructure (see ASCE's Report Cards on
the health of U.S. infrastructures).