4.3. Scenario Storylines
Although each of the four SRES storylines can unfold only if certain values
are emphasized more than others, no explicit judgments have been made by the
SRES team as to their desirability or probability. Storylines in the literature,
however, are often explicitly intended by their authors to have a positive or
negative connotation, and sometimes explicitly include assumed dominant or preferred
types of governance. Thus, the four SRES storylines are fundamentally different
in this respect compared to many narrative scenarios in the underlying literature.
Two arguments are pertinent to the linkage between the scenario storylines
and the underlying literature. First, a future regarded as negative by some
people may be perceived as positive by others. Second, the storylines represent
families of scenarios that can include both success and failure, depending on
the perspective of the beholder. To quote Wilkerson (1995): "Like the real life
from which they are drawn, the scenarios are mixed bags, at once wonderfully
dreadful and dreadfully wonderful." Importantly, the "neutral" or "agnostic"
character of SRES scenarios is an explicit departure from most of the underlying
literature about storylines and narrative scenarios.
Another important departure and an innovation unique to the SRES approach is
the use of the storylines in conjunction with multiple (six) modeling approaches
to develop and formulate a set of quantifications or scenarios that are overall
consistent with the underlying storylines. This approach provides a rigorous
modeling test of the underlying logic and structure of the storyline, while
the narrative aspect of the storyline provides a broader, descriptive context
for better understanding and interpretation of the scenarios.
4.3.1. A1 Storyline and Scenario Family
The A1 storyline is a case of rapid and successful economic development, in
which regional average income per capita converge - current distinctions between
"poor" and "rich" countries eventually dissolve. The primary dynamics are:
- Strong commitment to market-based solutions.
- High savings and commitment to education at the household level.
- High rates of investment and innovation in education, technology, and institutions
at the national and international levels.
- International mobility of people, ideas, and technology.
The transition to economic convergence results from advances in transport and
communication technology, shifts in national policies on immigration and education,
and international cooperation in the development of national and international
institutions that enhance productivity growth and technology diffusion.
This may be the type of scenario best represented in recent literature (e.g.,
Shinn, 1985; UN, 1990; Schwartz, 1991; Peterson, 1994; Gallopin et al., 1997;
Glenn and Gordon, 1997, 1999; Lawrence et al., 1997; Hammond, 1998; Raskin et
al., 1998). Such scenarios are dominated by an American or European entrepreneurial,
progress-oriented perspective in which technology, especially communication
technology, plays a central role. Wilkerson (1995) designed various scenarios
that share features with A1. They emphasize market-oriented solutions, high
consumption of both tangible and intangible commodities, advanced technology,
and intensive mobility and communication. In some examples of this type of scenario,
high economic growth leads to shifts of economic power from traditional core
countries to the current economic "periphery," as in the "Global Shift" scenario
by CPB (1992) and de Jong and Zalm (1991). The Shell scenario "New Frontiers"
(Shell, 1993) is also representative of this family. The IPCC Scenarios IS92a
and IS92e are well-known examples of futures with high levels of economic growth
(Leggett et al., 1992). IIASA and World Energy Council (WEC) jointly developed
three High Growth Scenarios that share assumptions on rapid technological progress,
liberalized trade markets, and rising income levels (Nakic´enovic´ et al., 1998).
In the A1 scenario family, demographic and economic trends are closely linked,
as affluence is correlated with long life and small families (low mortality
and low fertility). Global population grows to some nine billion by 2050 and
declines to about seven billion by 2100. Average age increases, with the needs
of retired people met mainly through their accumulated savings in private pension
The global economy expands at an average annual rate of about 3% to 2100, reaching
around US$550 trillion (all dollar amounts herein are expressed in 1990 dollars,
unless stated otherwise). This is approximately the same as average global growth
since 1850, although the conditions that lead to this global growth in productivity
and per capita incomes in the scenario are unparalleled in history. Global average
income per capita reaches about US$21,000 by 2050. While the high average level
of income per capita contributes to a great improvement in the overall health
and social conditions of the majority of people, this world is not necessarily
devoid of problems. In particular, many communities could face some of the problems
of social exclusion encountered in the wealthiest countries during the 20 th
century, and in many places income growth could produce increased pressure on
the global commons.
Energy and mineral resources are abundant in this scenario family because of
rapid technical progress, which both reduces the resources needed to produce
a given level of output and increases the economically recoverable reserves.
Final energy intensity (energy use per unit of GDP) decreases at an average
annual rate of 1.3%. Environmental amenities are valued and rapid technological
progress "frees" natural resources currently devoted to provision of human needs
for other purposes. The concept of environmental quality changes in this storyline
from the current emphasis on "conservation" of nature to active "management"
of natural and environmental services, which increases ecologic resilience.
With the rapid increase in income, dietary patterns shift initially toward
increased consumption of meat and dairy products, but may decrease subsequently
with increasing emphasis on the health of an aging society. High incomes also
translate into high car ownership, sprawling suburbia, and dense transport networks,
nationally and internationally.
Several scenario groups considered in the A1 scenario family reflect uncertainty
in the development of energy sources and conversion technologies in this rapidly
changing world. Some scenario groups evolve along the carbon-intensive energy
path consistent with the current development strategy of countries with abundant
domestic coal resources. Other scenario groups intensify the dependence on (unconventional)
oil and (in the longer-run) natural-gas resources5
. A third group envisages a stronger shift toward renewable energy sources and
conceivably also toward nuclear energy. A fourth group (which includes the A1B
marker scenario) assumes a balanced mix of technologies and supply sources,
with technology improvements and resource assumptions such that no single source
of energy is overly dominant. The implications of these alternative development
paths for future GHG emissions are challenging: the emissions vary from the
carbon-intensive to decarbonization paths by at least as much as the variation
of all the other driving forces across the other SRES scenarios.