Emissions Scenarios - IPCC

172 An Overview of Scenarios
of the general knowledge of this literature, and on the personal
experience and creativity within the writing team. The writing
team spent the better part of the first year (1997) formulating
the storylines, which during the following two years were
revised iteratively with the scenario development until the
completion of the repoit.
Four brief "future histories" captured by the SRES storylines
differ in how global regions interrelate, how new technologies
diffuse, how regional economic activities evolve, how
protection of local and regional environments is implemented,
and how demographic structure changes. The "qualitative"
storyline characteristics include various political, social,
cultural, and educational conditions (e.g., type of governance,
social structure, and educational level) that often cannot be
defined in strictiy quantitative tenns and do not directiy "drive"
GHG emissions. These qualitative variables, however,
participate in complex "cause-effect" relationships with
quantitative emission drivers (e.g., economic activities,
population levels, energy consumption). Their expficit
inclusion in the scenario development process not only makes
scenarios more "plausible" and "believable," but also ensures
they do not become an arbitrary numeric combination of
quantitative parameters.
The SRES storylines do not include explicit policies to limit
GHG emissions or to adapt to the expected global cHmate
change, reflecting the SRES Teitns of Reference (see Appendix
I). However, the storyline demographic, social, economic and
technological profiles can be used in other studies to develop
and evaluate climate-change mitigation and adaptation measures
and policies. Such evaluation would require additional
(prescriptive) assumptions about policies and measures to affect
future climates and human responses to climate change now
absent from the storylines.
All four SRES "futures" represented by the distinct storylines
are treated as equally possible and there are no "central,"
"business-as-usual," "surprise," or "disaster" futures (examples
of which are given in Box 4.2). All of the storylines have
features that can be inteipreted as "positive" or "negative" and
they play out different tendencies and changes in part visible in
the world today. To avoid the tendency to overemphasize
"positive" or "negative" features of individual storylines, their
titles were kept simple. Many attempts were made to capture
the spirit of each storyline with a short and snappy title, but no
single title was found to reflect adequately the complex mix of
characteristics of any storyline.
By 2100 the world will have changed in ways that are difficult
to imagine, as difficult as it was at the end of the 19"^ century
to imagine the changes of the 20"' century. However, each
storyline takes a different direction of future developments so
that they differ in an increasingly irreversible way. They
describe divergent futures that reflect a significant portion of
the underlying uncertainties in the main driving forces. The
differences among the storylines cover a wide range of the key
"future" characteristics, such as technology, governance, and
behavioral patterns. Hence the plausibility or feasibility of the
storyline assumptions should be viewed with an "open mind,"
not from a narrow interpretation of current situations and
trends in economic conditions, technology developments, and
social and governing structures.
The main characteristics of future developments that take
distinct development paths in the four storylines include (see
also Table 4-2 for an overview):
• Nature of the global and regional demographic developments
in relation to other characteristics of the storyline.
• Extent to which economic globalization and increased
social and cultural interactions continue over the 2P'
century.
• Rates of global and regional economic developments
and trade pattems in relation to the other characteristics
of the storyline.
• Rates and direction of global and regional
technological change, especially in relation to the
economic development prospects.
• Extent to which local and regional environmental
concems shape the direction of future development and
environmental controls.
Box 4-2: "Neutrality" of the SRES Scenarios
The SRES scenarios are mtended to exclude catastrophic fumres. Such catastiophic futures feature prominently in the Uterature.
They typically involve large-scale envnotunental or economic collapses, and extrapolate current unfavorable conditions and
trends in many regions. Promment examples of such scenarios include "Retrenchment" (Kinsman, 1990), "Dark Side of the
Market World" or "Change witiiout Progress" (Schwartz, 1991), "Black and Grey" (Godet et al, 1994), "Global Incoherence
Scenario" (Peterson, 1994), "New World Disorder" (Schwartz, 1996), "A Visit to Befindia" (Pohl, 1994), the future evoked by
the description of the current situation in parts of West-Africa and Central Asia (Kaplan, 1996), "Barbarization" (Gallopin et al,
1997), "Dark Space" (Glenn and Gordon, 1999), "Global Fragmentation" (Lawrence et al, 1997), and "A Passive Mean World"
(Glenn and Gordon, 1997, 1999). In this last scenario the world is carved up into three rigid and distinct trading blocs, with
fragmented political boundaries and out-of-control ethnic conflicts. In "Global Crisis" (de Jong and Zalm, 1991; СРВ, 1992)
protectionism leads to a vicious circle of slowing economic growth and eventually breakdown. Many of these scenarios suggest
that catastrophic developments may draw the world into a state of chaos within one or two decades. In such scenarios GHG
emissions might be low because of low or negative economic growth, but it seems unlikely they would receive much attention
in the light of more immediate problems. Hence, this report does not analyze such futures.